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Solan Production Chemical Permit SAT

Chemical Risk Assessment for Platform and SOST Installation, Commissioning and Operation

Solan Platform and SOST Installation, Commissioning and Production Chemical Risk Assessment

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North Sea Rev B17, November 2015

REV ISSUE DATE STATUS AMENDMENT DETAILS ORIGINATE

D BY APPROVED

B1 30/05/14 1st Draft Submitted for client review Genesis Genesis

B2 04/06/14 Final Client comments incorporated Genesis Genesis

B3 14/08/14 Variation 1 To add REDA chemicals Genesis Premier

B4 26/08/14 Variation 1 Version 2

Update to address Marine Scotland comments Genesis Premier


Update to address Marine Scotland comments Genesis Premier


Update to address Marine Scotland comments

Genesis Premier


Update to address Marine Scotland comments and amend to align with

changes to PLA/90 CP/342, 343 & 345 Genesis Premier


Update to add production chemicals Genesis Premier


Update to address Marine Scotland comments

Genesis Premier


Update to address client comments, update for biocide dosing of seawater

caisson and to reflect changes to PLA/90 CP/347 & 348

Genesis Premier


Update to address MS comments Genesis Premier


Update for additional application of EC6527G

Genesis Premier


Update to include new chemical permit (CP/tba) under PLA/90.

Genesis Premier


Update to EC6527G and addition of an EC6198A Application

Genesis Premier


Update to include additional pumps on the EC6198A application and add EC6527H

Genesis Premier


Increase of chemical usage, addition of chemicals and amendment to text.

Genesis Premier


Addition of biocide EC6718A and updates for discharge of ballast water during

commissioning Genesis Premier

This document contains proprietary information belonging to Premier and must not be wholly or partially reproduced nor disclosed without prior written permission from Premier.

The master copy of this document is held electronically within Premier’s Document Management System. If you are using a paper copy or a CD issue of this document, it is your responsibility to ensure it is the latest version.


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Rev B17, November 2015

1 CHEMICAL RISK ASSESSMENT

1.1 Background

This Chemical Risk Assessment forms part of the Chemical Permit SAT (CP/371)

which supports Production MAT (PRA/157) for the Installation, Commissioning and

Operational Phases of the operations at the Solan field. A Pipeline MAT (PLA/90)

and associated SATs were submitted in May 2014 to support the PWA and

DepCon applications.

Sections 2 to 4 of this Chemical Risk Assessment assess the installation and

commissioning phases and Sections 5 and 6 assess production operations at

Solan.


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2 INSTALLATION PHASE

2.1 Background

A chemical risk assessment has been carried out for the purpose of the proposed

Subsea Oil Storage Tank (SOST) installation operations. All the chemicals that are

planned to be used comply with OCNS and the Offshore Chemicals Regulations

2002 (as amended). Details of the chemicals that are planned to be used are in

the Chemical Permit SAT.

CHARM calculations have been undertaken, where applicable, to assess the

potential environmental risk of chemical discharges to sea from surface

installations. All discharges were modelled assuming a batch discharge;

assumptions for batch dilution factors are provided below.

Batch dilution factors (BDFs) are calculated from:

Density of the discharged fluid (normally equivalent to seawater), not the

density of the product. The permitted range within CHARM is 1.03 to 1.7

g/cm3.

Discharge rate of the discharged fluid. The permitted range within CHARM

is 60 to 180 m3/hour.

Total volume of fluid discharged. The permitted range within CHARM is 3

to 120 m3.

If the discharge parameters exceed the permitted range, the worst case BDF of

0.001 allowable within CHARM will be used. If the discharge parameters are below

the permitted range, the minimum values will be used to calculate a BDF of

0.000426. Note that BDFs are only calculated for chemicals that are discharged to

the environment and for which CHARM modelling is applicable.

Osborne Adams calculations were undertaken to assess the potential

environmental risk of the discharge of chemicals subsea. Discharge rates

assumed a discharge of 50 m3 over seven hours. In all instances T1 was found to

be more than T2, indicating that the releases will not have a significant effect on

the marine environment.

None of the chemicals proposed to be used in the operations have an RQ >1 / an

HQ >1 / SUB warning / OCNS category of A, B or C.


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None of the chemicals proposed to be used in these operations were found to

present a risk to the environment; therefore, the overall effects of marine

discharges on the benthic communities and the marine environment are not

expected to be significant.

2.2 Description of Chemical Use

During the seven hour SOST installation period the tank was flooded and lowered

to the seabed. The SOST has flooding valves in its base and vent valves at the top

to allow water from beneath to displace the air. The SOST was pre-dosed onshore

with corrosion inhibitor, biocide and dye (see Table 2-1) which, as the interior filled

with seawater, was diluted to the required dosage. The tank was free flooded with

a contingency air supply connected to ensure a controlled descent.

Once the tank was set down the flood and vent valves were closed and the vessels

and air lines disconnected. No egress of water occurred however a contingency of

50 m3 discharge was included.

The remaining chemicals will be retained in the system before being flowed back to

the platform via the 12” water return line prior to being discharged to sea during the

first fill of the tank.

For additional details of the SOST please see Section 2.2 of the EIA Justification.

Table 2-1 Chemical Summary

Chemical

Name

Chemical

Function

Application

Type

Cefas

Template

Product

Label

Action

Level Category

Expiry

Date

RO IM B221 Biocide Batch 1 - - Gold 10/09/16

RO HY M738 Dye Batch 1 - - Gold 19/07/16

RO HY M700 Oxygen

scavenger Batch 2 - - Gold 26/02/16

Following on from the SOST installation as described above, once the tank is on

the seabed, the valves used for flooding the tank will be removed in order to fit

blank plates and REDA chemical sticks will be inserted (see Table 2-2).

Although the storage tank already contains a Biocide, Dye and Oxygen Scavenger,

further products are required as several vent/flooding valves are to be cut and

flange connections are to be disconnected and replaced with blind flanges.


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Chemical sticks will be inserted at each new flange connection where tank

containment is broken.

24 flanged joints will be made up with 100 g RO HY C350, 100 g RO HY B238,

100 g RO HY V658 and 100 g RO HY M779 chemical sticks. Subsea discharge of

chemical sticks is not expected during the course of this operation. However, as a

worst case, it is assumed up to 10 g RO HY C350, 10 g RO HY B238, 10 g RO HY

V658 and 10 g RO HY M779 (10% of each stick mass) may partially dissolve /

discharge subsea during insertion of the sticks at each flanged connection.

The remaining chemicals will be retained in the system before being flowed back to

the platform via the 12” water return line prior to being discharged to sea during the

first fill of the tank.

10% discharge of RO HY C350, RO HY B238, RO HY V658 and RO HY M779 has

been modelled using the Osborne-Adams method and the results show that they

are unlikely to have an impact on the marine environment (see Appendix A). The

further 90% discharge has been assessed using CHARM and all RQs generated

are <1, indicating that the discharges will not have a significant impact on the

marine environment.

The total volume of the SOST is estimated at 50,000 m3 and this has been used to

calculate dosages after dilution. This volume is sufficiently great to also allow for

the volume of fluid flowed into the tank from the pipelines. A summary of the

discharges is presented in Table 3-1.

Table 2-2 Chemical Summary

Chemical

Name

Chemical

Function

Application

Type

Cefas

Template

Product

Label

Action

Level Category

Expiry

Date

RO HY

B238 Biocide Batch 2 SUB 4 Gold 16/07/2015

RO HY

C350

Corrosion

Inhibitor Batch 2 SUB 4 Gold 21/07/2015

RO HY

M779 Dye Batch 2 SUB 4 Gold 16/07/2015

RO HY

V658 Stick

Oxygen

Scavenger Batch 3 SUB 4 Gold 16/07/2015


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The supplier (REDA) does not intend to fully certify RO HY B238, RO HY C350,

RO HY M779 and RO HY V658 Sticks. The six month field trial templates were

applied for as the current formulation of the products attracts a substitution warning

after review of the first sets of ecotox data. The substitution warning for the

products is due to the binder used, as discussed in the justification. Therefore

REDA does not intend to fully certify the materials as they are already actively

working on replacements with improved environmental characteristics.

The function of the products in the storage tank is identical to their function during

the six month field trial for pipeline hydrotesting.

The fate of the chemicals left in the system after installation of the pipelines and

tank will be either:

displaced downhole;

discharged to sea from the topsides during the first fill of the SOST; or

flowed to the tanker during the first cargo off-load.


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3 SOST COMMISSIONING / FIRST FILL

After the first cargo off-load there will be no discharge of production chemicals to

sea, unless necessary for the commissioning of equipment in order to ensure long

term discharges are minimised. A commitment was made in the Environmental

Statement that production will be shut in when water injection is not available.

The P2 well will not be available at the time of first oil. At first oil, all installation

chemicals in P1 infield pipelines will be flowed to the topsides with the produced

fluids, then on to the tank where they will partition into the water phase, and then

back to the platform via the 12” water return line prior to being discharged to sea

during the first fill of the tank.

All installation chemicals in the 10” oil export line will be flowed to the tank, then

back to the platform via the 12” water return line prior to being discharged to sea

during the first fill of the tank.

All installation chemicals in the 12” ballast water line will be flowed to the platform

and discharged to sea during the first fill of the tank.

All installation chemicals in the SOST will be flowed back to the platform via the 12”

water return line prior to being discharged to sea during the first fill of the tank.

During the first cargo offloading from the tank, all the installation chemicals in the

24” displacement line will be flowed in to the tank. During the subsequent tank fill it

is expected that these chemicals will flow back to the platform via the 12” ballast

water return line prior to being injected down hole. However, there is the potential

for these chemicals to be discharged to sea during first fill therefore this has been

risk assessed as part of the chemical permit SAT (PRA/157 CP/371).

During the first cargo offloading from the tank, all the installation chemicals in the

offloading system (i.e. the 24” offloading line and the OLS and the hose) will be

offloaded to the tanker. The exception to this is the chemical sticks used in SOST

remedial works. These chemicals sticks will be discharged to sea during first fill

therefore this has been risk assessed as part of the chemical permit SAT (PRA/157

CP/371).


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During the initial water injection, the chemicals left in the W1 & W2 infield pipelines

will be flowed downhole and will not be discharged to sea.

A total of 1.6 kg of RO HY B238, 1.6 kg of RO HY C350, 1.6 kg of RO HY M779

and 1.6 kg of RO HY V658 is calculated for the chemicals remaining in the

pipelines. The use of these chemicals has previously been permitted and therefore

only their discharge is applied for here.

These discharges have been added to those applied for in this permit (i.e. the

sticks inserted following installation of the SOST, 1.08 kg of RO HY B238, 1.08 kg

of RO HY C350, 1.08 kg of RO HY M779 and 1.08 kg of RO HY V658) to give a

total of 2.86 kg of RO HY B238, 2.86 kg of RO HY C350, 2.86 kg of RO HY M779

and 2.86 kg of RO HY V658 which will be discharged to sea.

A total of 318.63 kg of Monoethylene Glycol (and all dilutions) (Reda), 25.48 kg of

RO IM B221 and 6.04 kg of RO HY M738 is calculated for the chemicals remaining

in the pipelines. These have been added to the chemicals already in the SOST

(pre-fill) to give a total of 22,948.48 kg of RO IM B221, 5,439.64 kg of RO HY M738

as well as 32,092.2 kg RO HY M700 remaining in the SOST.

The total volume of the SOST is estimated at 50,000 m3 and approximately

7,500 m3 discharge has been accounted for during tie-ins. The remaining volume of

42,500 m3 has been used to calculate dosages after dilution. This volume is

sufficiently greater to also allow for the volume of fluid flowed into the SOST from

the pipelines. A summary of the discharges is presented in Table 3-1.

These discharges have been modelled using CHARM (with the exception of MEG

which is PLONOR and OCNS E) and all RQs generated are <1 (with the exception

of RO HY M700 which is further justified), indicating that the discharges will not

have a significant impact on the marine environment.

A BDF of 5.3E-04 was calculated using the density of seawater (1.031 g/cm3), a

rate of 60 m3/h (the minimum available in the EOSCA calculator) and a volume of

120 m3 based on a worst case total discharge volume of 1000 m3/day, see EIA

Justification MAT Table 4.1. This is based on the annual oil production rate. The

rate at which oil enters the SOST determines the rate at which water is flushed out


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of the SOST. A figure of 1,000 m3/day has been used in order to account for

potential variation in the rate of oil production and to ensure that the worst case

potential discharge volume per day is assessed.

None of the chemicals proposed to be used in these operations were found to

present a risk to the environment; therefore, the overall effects of marine

discharges on the benthic communities and the marine environment are not

expected to be significant.

3.1 Solan Umbilical Displacement Chemicals

Flushing of the umbilical chemical cores is critical for start-up operation. The

shipping fluid contained in the umbilical chemical cores, and if applicable the

spacer chemicals required to displace it, will be displaced to the reservoir before

commencing the initial start-up (at least one week in advance). This will ensure

production chemical availability at the wellhead/downhole injection point concurrent

with production. These activities will take place during the Hook-Up and

Commissioning (HUC) phase.

The current chemical permit covers the routine chemical injection operations

required during routine production activities. In addition, a one-off displacement

operation is required for each umbilical during HUC. As per routine operations this

activity will displace all umbilical fluids downhole with no expected discharge to

sea.

During commissioning, the Aquaglycol 24F left in the umbilicals will be displaced

downhole. A mutual solvent will be used to clean the umbilicals prior to charging

with production chemicals. The mutual solvent will also be discharged down hole.


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Table 3-1 Summary of discharges

PLA-90 CP-342

PLA-90 CP-345

PLA-90 CP-346

PLA-90 CP-347

PLA-90 CP-348

SUB TOTAL PRA-157 CP-371

TOTAL Discharge

dosage (mg/l)

RX-5720 0.9 0.90 0.021

RX-1228 0.9 0.90 0.021

RX-5207 0.9 0.90 N/A

RX-9034A 0.45 0.45 0.011

RO HY C350 0.34 0.18 0.18 1.08 1.60 1.08 2.86 0.067

RO HY B238 0.34 0.18 0.18 1.08 1.60 1.08 2.86 0.067

RO HY M779 0.34 0.18 0.18 1.08 1.60 1.08 2.86 0.067

RO HY V658 0.34 0.18 0.18 1.08 1.60 1.08 2.86 0.067

RO IM B221 2.28 13.91 9.29 25.48 22923.00 22948.48 540

RO HY M738 0.54 3.30 2.20 6.04 5433.60 5439.64 128

RO HY M700 0.00 32092.20 32092.20 756

RX-5227 56.33 56.33 1.325

RX-9022 10.12 10.12 0.238

MEG (REDA) 46.57 182.67 89.39 318.63 N/A


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4 CHEMICAL JUSTIFICATIONS FOR INSTALLATION AND COMMISSIONING

This section gives a detailed description of and justification for the chemicals to be used

during installation and commissioning. Further risk based justification has been included in

the following circumstances:

Where RQs >1;

HQ>1 (Silver, White, Orange, Blue and Purple);

Chemicals contain components identified for substitution; or

Non-CHARMable chemicals with OCNS groups that indicate a significant toxic

potential (i.e. OCNS category A, B or C).

Chemical name MEG (and all dilutions) Supplier REDA Oilfield UK Ltd

Function Other Injection point n/a

Treatment philosophy and application

MEG (and all dilutions) remaining in the pipelines will be discharged topsides on start-up. A total of 318.2 kg will be discharged. This is not expected to have a significant impact on the marine environment as it is a small amount and this product is PLONOR and HQ Category E.

PLONOR HQ category E Identified for substitution

RQ N/A

Chemical name RO IM B221 (1 of 2) Supplier REDA Oilfield

Function Biocide Injection Point n/a


RO IM B221 is a biocide which was pre-dosed into the SOST onshore. As the tank was lowered into position on the seabed, the interior filled with seawater (via flooding valves in the bottom), which diluted RO IM B221 to the required dosage. Air was displaced from vent valves in the top of the tank.

No egress of water occurred however a contingency of 50 m3 discharge has been included in the chemical permit application.

The tank will remain filled with seawater until commissioning. Treatment with RO IM B221 biocide is therefore required to preserve the integrity of the tank.

The discharge has been modelled using the Osborne-Adams method and T1>T2 therefore it is unlikely to have an impact on the marine environment (see Appendix A). The remainder of the chemical will be retained in the system during installation and then will be discharged via topsides and has been risk assessed using CHARM.

PLONOR HQ category Gold Identified for substitution

RQ n/a

CHARM data Assumptions

Dosage 540 mg/l Seawater will enter the tank (through valves on the underside) and air and chemical egress will leave the tank (though valves on the topside) over the 7 hour operation period.

Fraction discharged 0.1%

CHARM algorithm code CNA Discharge code OTH


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Chemical name RO IM B221 (2 of 2) Supplier REDA Oilfield



RO IM B221 is a biocide which was pre-dosed into the SOST onshore.

0.1% of the chemical will be discharged during installation and the remainder will be discharged via topsides and has been risk assessed using CHARM.


RQ <1


Dosage 540 mg/l Following the potential 0.1% discharge subsea during installation, the remainder of the chemical will be retained in the system until commissioning when it will be discharged from the topsides. Fraction discharged 99.9 %

CHARM algorithm code CWO Discharge code BAT

Chemical name RO HY M738 (1 of 2) Supplier REDA Oilfield

Function Dye Injection Point n/a


RO HY M738 is required to check for leaks in the system. RO HY M738 is a dye which was pre-dosed into the SOST onshore. As the tank was lowered into position on the seabed, the interior filled with seawater (via flooding valves in the bottom), which diluted RO HY M738 to the required dosage. Air was displaced from vent valves in the top of the tank.




RQ n/a


Dosage 128 mg/l Seawater will enter the tank (through valves on the underside) and air and chemical egress will leave the tank (though valves on the topside) over the 7 hour operation period.

Fraction discharged 0.1%


Chemical name RO IM M738 (2 of 2) Supplier REDA Oilfield



RO HY M738 is required to check for leaks in the system. 0.1% of the chemical was discharged during installation and the remainder will be discharged via topsides and has been risk assessed using CHARM.


RQ <1


Dosage 128 mg/l Following the potential 0.1% discharge subsea during installation, the remainder of the chemical will be retained in the system until

Fraction discharged 99.9 %


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commissioning when it will be discharged from the topsides.



Function Oxygen scavenger Injection Point n/a


RO HY M700 is a corrosion inhibitor which was pre-dosed into the SOST onshore. As the tank was lowered into position on the seabed, the interior filled with seawater (via flooding valves in the bottom), which diluted RO HY M700 to the required dosage. Air was displaced from vent valves in the top of the tank.


The tank will remain filled with seawater until commissioning. Treatment with RO HY M700 oxygen scavenger is therefore required to preserve the integrity of the tank.



RQ n/a


Dosage 756 mg/l Seawater will enter the tank (through valves on the underside) and air and chemical egress will leave the tank (though valves on the topside) over the 7 hour operation period. Fraction discharged 0.1%



Function Oxygen Scavenger Injection Point n/a


RO HY M700 is a corrosion inhibitor which was pre-dosed into the SOST onshore. 0.1% of the chemical will be discharged during installation and the remainder will be discharged via topsides and has been risk assessed using CHARM.


RQ >1


Dosage 756 mg/l Following the potential 0.1% discharge subsea during installation, the remainder of the chemical will be retained in the system until commissioning when it will be discharged from the topsides. Fraction discharged 99.9 %


Justification:

An RQ = 4.2 was generated for the discharge of RO HY M700, therefore its discharge may have an impact on the marine environment. A dosage higher than the Cefas template dosage was required due to treatment duration and mode of deployment.

Due to its surface active nature it will adsorb onto particles while it is contained within the SOST therefore due to its adsorption and biodegradation properties it will have low bio availability when ultimately released to the marine environment, anticipated to be approximately 3 months after the initial fill. RO HY M700 is biodegradable and will disperse rapidly when released. The product is water soluble and the hydrodynamic regime around the Solan area is generally energetic enough to ensure that any discharge will be rapidly diluted and dispersed, minimising any potential impact on the marine environment


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Chemical name RO HY B238 (1 of 2) Supplier REDA Oilfield



RO HY B238 is a biocide stick which was inserted after flooding of the tank and before the blank plates are fitted.

A worst case discharge of 10% of the stick mass during insertion has been assumed. With the exception of the 10% release during insertion, the rest of the chemical will be retained in the system during installation and then discharged from the topsides during commissioning. 10% discharge has been modelled using the Osborne-Adams method and T1>T2 therefore it is unlikely to have an impact on the marine environment (see Appendix A). The remaining 90% will be discharged via topsides and has been risk assessed using CHARM.


RQ n/a


Dosage 120 mg/l (10% of each stick mass) may partially dissolve / discharge subsea during insertion of the sticks at each flanged connection. The remaining chemical will be retained in the system until commissioning when it will be discharged from the topsides.

Fraction discharged 10 %


Justification:

The REDA Sticks have a SUB warning due to the use of a Polyethylene Glycol binder which is used as the binder/matrix to hold the active ingredients, which shows poor biodegradation. The toxicity is also high (worst case aquatic toxicity of 3.35 mg/l) which is necessary to fulfil its purpose as a biocide.

In order to develop substitution free versions REDA Oilfield are continuing to review and develop formulations and options to improve the stick binder package, moving to lower molecular weight polyethylene glycols which are expected to have improved biodegradation. Simultaneously we are also exploring other binding options to eliminate the substitution warnings from this range of products.

Osborne Adams modelling has shown that any subsea discharge is not likely to have a significant impact on the marine environment.

The manufacturer is aware that this product is a UK National Plan level 4 chemical and that it must be replaced, or discharges to the marine environment eliminated, or continued use and/or discharge must be formally justified by the end of December 2016.

Chemical name RO HY B238 (2 of 2) Supplier REDA Oilfield



RO HY B238 is a biocide stick which was inserted after flooding of the tank and before the blank plates are fitted.

90% of the chemical will be retained in the system during installation and then discharged subsea during commissioning. This 90% will be discharged via topsides and has been risk assessed using CHARM.


RQ <1


Dosage 0.067 mg/l Following the potential 10% discharge subsea during insertion of the sticks, the remaining 90% of chemical will be retained in the system until commissioning when it will be discharged from the topsides.




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Justification:

The REDA Sticks have a SUB warning due to the use of a Polyethylene Glycol binder which is used as the binder/matrix to hold the active ingredients, which shows poor biodegradation. The toxicity is also high (worst case aquatic toxicity of 3.35 mg/l) which is necessary to fulfil its purpose as a biocide.


CHARM modelling has shown that the discharge from the topsides is not likely to have a significant impact on the marine environment.


Chemical name RO HY C350 (1 of 2) Supplier REDA Oilfield

Function Corrosion Inhibitor Injection Point n/a


RO HY C350 is a corrosion inhibitor stick which was inserted after flooding of the tank and before the blank plates are fitted.



RQ n/a



Fraction discharged 10%


Justification:

The REDA Sticks have a SUB warning due to the use of a Polyethylene Glycol binder which is used as the binder/matrix to hold the active ingredients, which shows poor biodegradation. The toxicity is also high (worst case aquatic toxicity of 1.02 mg/l).




Chemical name RO HY C350 (2 of 2) Supplier REDA Oilfield

Function Corrosion Inhibitor Injection Point n/a



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RO HY C350 is a corrosion inhibitor stick which was inserted after flooding of the tank and before the blank plates are fitted.



RQ <1


Dosage 0.067 mg/l Following the potential 10% discharge subsea during insertion of the sticks, the remaining 90% of chemical will be retained in the system until commissioning when it will be discharged from the topsides. Fraction discharged 90 %


Justification:

The REDA Sticks have a SUB warning due to the use of a Polyethylene Glycol binder which is used as the binder/matrix to hold the active ingredients, which shows poor biodegradation. The toxicity is also high (worst case aquatic toxicity of 1.02 mg/l).







RO HY M779 is a dye stick which was inserted after flooding of the tank and before the blank plates are fitted.



RQ n/a






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Justification:

The REDA Sticks have a SUB warning due to the use of a Polyethylene Glycol binder which is used as the binder/matrix to hold the active ingredients, which shows poor biodegradation. It is not likely to be toxic (worst case aquatic toxicity of 177.8 mg/l).







RO HY M779 is a dye stick which was inserted after flooding of the tank and before the blank plates are fitted.



RQ <1




Justification:





Chemical name RO HY V658 Stick (1 of 2) Supplier REDA Oilfield



RO HY V658 Stick is an oxygen scavenger stick which was inserted after flooding of the tank and before the blank plates are fitted.

A worst case discharge of 10% of the stick mass during insertion has been assumed. With the exception of the 10% release during insertion, the rest of the chemical will be retained in the system during installation and then discharged from the topsides during commissioning. 10% discharge has been modelled using the Osborne-Adams method and T1>T2 therefore it is unlikely to have an impact on the marine environment (see Appendix A). The remaining 90% will be discharged via topsides and has been risk assessed


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using CHARM.


RQ n/a





Justification:





Chemical name RO HY V658 Stick (2 of 2) Supplier REDA Oilfield



RO HY V658 Stick is an oxygen scavenger stick which was inserted after flooding of the tank and before the blank plates are fitted. 90% of the chemical will be retained in the system during installation and then discharged subsea during commissioning. This 90% will be discharged via topsides and has been risk assessed using CHARM.


RQ <1




Justification:


In order to develop substitution free versions REDA Oilfield are continuing to review and develop formulations and options to improve the stick binder package, moving to lower molecular weight polyethylene glycols which are expected to have improved biodegradation. Simultaneously we are also exploring other binding options to eliminate the substitution warnings from this range of products. CHARM modelling has shown that the discharge from the topsides is not likely to have a significant impact on the marine environment.



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4.1 Osborne Adams Calculations


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5 PRODUCTION PHASE

In the production phase, the Solan development will require a high level of

chemical treatment and production chemistry management, including:

Produced oil and water treatment chemicals:

o Asphaltene Inhibitor

o Biocide

o Demulsifier

o Oil Antifoam

o Scale Inhibitor

Seawater injection treatment chemicals:

o Biocide

o Oxygen Scavenger

o Scale inhibitor

o Water Antifoam

Detergent / cleaning fluids to maintain topsides

The following document details the chemicals required, dosage rates, quantities

and injection points. Solan will operate as a closed system once online and there

are no planned discharges of production chemicals, with the exception of

chlorination, which will take place routinely in the seawater system to control the

potential blockage of pipes and corrosion. Discharges of installation chemicals will

occur as a one-off during first fill. There are no planned discharges occurring

thereafter as Premier are committed to no production without re-injection. The

exceptions are utility products such as detergents and hydraulic fluids which may

occasionally be discharged. Any discharge of these products has been fully risk

assessed.

All chemicals specified for use in the Solan development and on this application

are registered with CEFAS as per standard Premier procedures. The most up to

date CEFAS ranked list was used to source templates in order to complete this

application. Premier will continue to liaise with chemical suppliers to ensure that

the chemicals will be re-registered or will be submitted for re-registration at the

appropriate time (generally 8-weeks prior to the expiry date).

During initial start-up and commissioning of the process, continuing past the first fill

of the SOST, ballast water from the SOST will be discharged to sea. The first fill

overboard discharge volume is anticipated to be 406,000 m3. This is expected to

take 3 months.


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Post first fill of the SOST the water injection system will be commissioned. When

available, all ballast water will be re-injected and discharge to sea will only occur if

the system is unavailable. The expected uptime post commissioning of the water

injection system is 95%. Should the water injection system become unavailable

ballast water will be discharged to sea via the sea water disposal caisson C-4801.

CHARMable chemicals have undergone a chemical risk assessment using

CHARM in order to estimate the potential for adverse impact on the marine

environment as a result of discharges from Solan. The risk assessment has taken

into account the total fluids volumes (see Table 5-1) to calculate the Risk Quotient

(RQ).

The daily volumes in Table 5-1 have been calculated using the P10 profile in order

to assess the worst case scenario in terms of environmental impact. The

availabilities used in the profiles are as follows:

No water injection facility initially for approximately 3 months; and

Water injection uptime of 95% to begin three months after first oil.

These figures represent the worst case in terms of potential environmental impact

and are all annual averages with operational efficiencies applied, therefore, these

figures may differ from those presented elsewhere.

Table 5-1 Production data used in CHARM

The general assumptions made in the preparation of this application and during the

calculations of the RQs are detailed in Section 6. Specific assumptions for each

product are detailed in the relevant justification.

Year Total fluids

(m3/day)

Oil production

(m3/day)

Produced water

(m3/day)

Ballast water

(m3/day)

Seawater Injection (m3/day)

Total Water

Injection (m3/day)

2015 0 0 0 0 0 0

2016 1,618 1,618 0 1,618 162 1,780

2017 2,485 2,485 0 2,485 248 2,733


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5.1 Production/Process Chemicals

A number of production chemicals will be utilised in the Solan process stream to

increase the efficiency of the production processes and to protect the integrity of

the production and export facilities and the reservoir. These production chemicals

provide a wide range of functions including prevention of scale and improving the

separation of oil in water during processing.

5.2 Produced Water Treatment

A water injection system is installed to inject treated produced water and treated

seawater into the reservoir in order to maintain the required pressures and optimise

oil and gas production. Products used within the PWRI system do not end up in the

marine environment as they are contained downhole and Premier is committed to

“no production without re-injection”.

The products listed under continuous use/discharge for 2015 are not part of the

preservation fluid and will be used when production begins at Solan. All water

produced and used through Solan is planned to be reinjected. If the seawater and

produced water reinjection facilities are down then the field will be shut in until this

is back online.

5.3 Seawater Treatment

Seawater is required to make up any shortfall of re-injection water below the

required injection rate. It undergoes treatment before co-mingling with produced

water and ballast water returned from the SOST (see Figure 5-1).

Seawater is lifted via pumps, dosed with sodium hypochlorite generated in situ and

passed through coarse filters. The filtered seawater is then directed to two

locations either injection or cooling water systems. The injection water is directed to

the fine filters and deaerator where oxygen scavenger is injected along with water

antifoam. Biocide will be injected into the system as required. The treated seawater

is not planned to be discharged as it is re-injected and contained downhole. The

cooling water is routed as cooling medium for all platform users before being

routed overboard via the sea water disposal caisson.

5.4 Water Injection System

A scale inhibitor is injected into the water injection system (produced water, treated

seawater and ballast water returned from the SOST) before produced water and

seawater mix prior to injection into the reservoir (see Figure 5-1). The injection


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quality water is not planned to be discharged as it is re-injected and contained

downhole.

5.5 SOST Biocide

The SOST is constructed from carbon steel as is the internal pipework. There is a

high risk of corrosive bacteria forming, particularly biofilms, therefore biocidal

protection is essential to protect the integrity of the SOST and internal pipework.

This will only be used from start-up from the first fill of the SOST with oil. The

application of biocide will be reduced as required based on a robust monitoring and

sampling regime.

There is a high risk of bacterial growth in the SOST because raw seawater will be

used for displacement, which will contain bacteria and is oxygenated. The

seawater will then be allowed to sit in stagnant conditions ideal for the proliferation

of biofilm that leads to microbial influenced corrosion. Therefore, a biopenetrant is

required to prevent establishment and aid removal of biofilm.

A glutaraldehyde based product (EC6178A) is required to protect the SOST.

EC6718A carries a substitution warning, but considering its performance compared

to industry standard, single component formulations, it is considered that this is the

best possible option to protect the Solan SOST from the threat of microbiological

influenced corrosion. There are non-SUB products (those without surfactants)

available but these products do not provide the bio-penetration required in this

application to combat biofilm which has the potential to be a significant problem in

the SOST.

A more environmentally friendly biocide is available (EC6527H) and testing has

shown that this product is likely to be effective in the water injection system but not

the SOST system. EC6527H is a tetrakis hydroxymethyl phosphonium sulphate

(THPS) based product which degrades relatively fast, providing a potential food

source for bacteria. If biofilms are established, a much higher biocide concentration

is then required. THPS has no biofilm penetration properties, so must be used with

a surfactant to improve efficacy.


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Figure 5-1 Process Flow Diagram - Seawater Treatment and Water Re-Injection with chemical injection points highlighted


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5.6 Utility Chemicals

5.6.1 Cleaning Chemicals

There are requirements for various detergent/cleaning materials including general

purpose rig wash to clean light hydrocarbons from the platform decks and turbine

wash used to perform offline washes to maintain turbine integrity. There will be

zero discharge of these chemicals as they will mix with fluid in the drainage system

and be re-injected. Cleaning chemicals will be discharged to sea via the sea water

disposal caisson C-4801.

5.6.2 Hydraulic Fluid

Hydraulic fluid is used to maintain pressure in the subsea system and to actuate

control valves and to prevent the ingress of seawater.

5.7 Annual Usage Figures

A contingency factor of 10% has been built in to the annual usage figures for all

products. Therefore, it is not possible to directly convert tonnages into dosage in

the case of continuously used chemicals. The injection rates are decided following

multidisciplinary assessment, laboratory experimentation, manufacturer

recommendations and field results. It is from these results, combined with the

forecast production data and resultant effect on processing conditions, that the

estimated annual quantity is calculated.

For multi-well batch treatment operations environmental modelling has been

performed on the maximum batch size used in the operation to represent a worst

case scenario. However, a unique batch size is calculated for every well dependent

on a number of factors including the flow characteristics and distance from the

point of chemical injection to required chemical treatment. Therefore, the total use

recorded for batch use products will not always correspond to the number of wells

to be treated multiplied by the maximum batch use. The total use may be lower as

not all wells will be treated with the maximum batch size. Batch chemicals do not

contain a contingency threshold, as each operation differs in nature and realistic

estimates are difficult to quantify.


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6 CHEMICAL JUSTIFICATIONS FOR PRODUCTION OPERATIONS

This section gives a detailed description of and justification for the chemicals to be

used during production operations, seawater treatment, water injection treatment

and utility systems. For each chemical used, its name, application stream, use and

Action Level (if applicable) is summarised in Table 6-1. The injection and discharge

points of each chemical are summarised in Table 6-2.

Further risk based justification has been included in the following circumstances:

Where RQs >1;

HQ>1 (Silver, White, Orange, Blue and Purple);

Chemicals contain components identified for substitution; or

Non-CHARMable chemicals with OCNS groups that indicate a significant

toxic potential (i.e. OCNS category A, B or C).


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Table 6-1 Summary of Chemicals Used

Chemical Name Chemical

Type

Application Process

Stream

Application

Type

Cefas

Template

Number

Product

Label

Action

Level Category

Expiry

Date

ASPH11742A Asphaltene

Inhibitor Production/Process Continuous 1 - - Gold 02/07/18

EC2217A Emulsion

Breaker Production/process Continuous 13 - - Gold 08/02/17

EC6004A Aromatic

Solvent Production/process Batch 15 - - Silver 04/04/17

EC9242A Oil Antifoam Production/process Continuous 10 SUB Level 4 Gold 14/08/16

EC9610A Mutual Solvent Production/process Batch 12 - - Gold 04/08/17

FX2443 Scale Inhibitor Production/process Continuous 7 - - Gold 01/04/18

Methanol Gas Hydrate

Inhibitor Production/process Batch 5 - - E 05/09/17

EC6527G Organic

Biocide

Production/process /

Seawater treatment Batch 5 - - Blue 23/10/18

EC6527H Organic

Biocide


Seawater treatment Batch 1 - - Gold 19/06/17

EC6718A Organic

Biocide


Seawater treatment Batch 3 SUB Level 2 Gold 11/02/16

EC6198A Biocide Seawater treatment Continuous 9 - - E 01/03/17

EC6213A Oxygen

Scavenger Seawater treatment Continuous 9 - - E 01/04/17


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Chemical Name Chemical

Type

Application Process

Stream

Application

Type

Cefas

Template

Number

Product

Label

Action

Level Category

Expiry

Date

EC9029A Water

Antifoam Seawater treatment Continuous 10 - - Gold 23/05/17

Sodium

hypochlorite

(generated in situ)

Biocide Seawater treatment Continuous 9 - - E 02/02/17

Oceanic HW 443 Hydraulic Fluid Utilities Batch 98 SUB Level 4 D 20/11/158

SOBO S GOLD 08 Detergent /

Cleaning Fluid Utilities Batch 7 - - Gold 03/07/17

ZOK 27 GS Detergent /

Cleaning Fluid Utilities Batch 4 - - Gold 23/07/18


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Table 6-2 Summary of injection and discharge points

Chemical Name

Injection Point Discharge Point Risk

Assessment

Production / Process

ASPH11742A 1 of 1 Downhole to production wells Zero discharge –

exported with oil Not required

EC2217A 1 of 1 Subsea trees (P1 and P2) and inlet to 1st stage separator

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

RQ<1

EC6004A 1 of 1 Downhole to production wells Zero discharge –


EC6718A 1 of 4 Oil export line (downstream of the 2nd

stage separator)

Zero discharge – re-

injected (worst case

discharged

overboard via SW

caisson)

RQ<1

EC9242A 1 of 1 1st and 2nd stage separators Zero discharge –


EC9610A 1 of 1 Downhole to production wells

Zero discharge –

re-injected or

exported with oil

(miscible in both

phases) (worst case

discharged

overboard via SW

caisson)

RQ<1

FX2443 1 of 2 Production wells

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

N/A

Methanol 1 of 1 Production Wells

Zero discharge –

re-injected or

exported with oil

(miscible in both

phases) (worst case

discharged

overboard via SW

caisson)

Non-

CHARMable

Seawater Treatment

EC6198A 1 of 1

SW Displacement Lift Pumps, Fire

Pump, Skim Pump, Ballast Pumps,

SW Displacement Pumps and water

injection booster pumps.

Discharged

overboard via SW

caisson

Non-

CHARMable


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Chemical Name


Assessment

EC6213A 1 of 1 Deaerator tower

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

Non-

CHARMable

EC6718A 2 of 4 Upstream of SW Displacement Inlet

Caisson

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

RQ<1

EC6527G/

EC6527H/ 1 of 3

SW Displacement Lift Caisson, Fire

Pump Caisson, Drains Pump Caisson

Discharged

overboard via SW

caisson

RQ<1

EC6527G/

EC6527H/ 2 of 3 Umbilical J-Tubes (J2, J4 & J5)

Zero discharge –

closed system Not required

EC9029A 1 of 1 Deaerator tower

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

RQ<1

Sodium

hypochlorite

(generated in situ)

1 of 1

SW lift system, Fire Water System,

Platform Utilities and Cooling Water

System

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

Non-

CHARMable

Water Injection

EC6718A 3 of 4 Upstream of Water Injection

Discharged

overboard via SW

caisson

RQ<1

FX2443 2 of 2 Water Injection – Upstream of PW &

SW mixing point

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

N/A

Drains

EC6527G/

EC6527H/ 3 of 3 Closed drains

Zero discharge – re-

injected Not required

EC6718A 4 of 4 Open drains

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

RQ<1

Utility Chemicals


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Chemical Name


Assessment

Oceanic HW 443 1 of 1 Subsea controls Discharged subsea T1>T2 (OA -

Section 6.5)

SOBO S GOLD 08 1 of 1 Solan topsides

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

RQ<1

ZOK 27 GS 1 of 1 Turbines

Zero discharge –

re-injected (worst

case discharged

overboard via SW

caisson)

RQ<1


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6.1 Production / Process

Chemical name ASPH11742A Supplier Nalco Champion

Function Asphaltene inhibitor Injection Point Downhole to production wells


ASPH11742A will be used to downhole in order to inhibit the formation of asphaltenes. Asphaltene inhibitor will be required from initial crude production whilst properties of the crude are verified under operating and laboratory conditions to decide whether ongoing injection is required. There is the requirement to initially fill the tank and then the chemical line. Dosage shall be via a downhole chemical injection line to below the ESP intake and as deeply set as possible. The asphaltene inhibitor is continuously dosed at a concentration of 100 313 mg/l based on the produced fluids oil rate.

Asphaltene deposition tends to alleviate with the onset of water production and in general high water rates are predicted in the Solan development. Consequently asphaltene inhibitor may only be required for the first few years of production; to be confirmed by operational experience.

PLONOR HQ

category Gold

Identified for substitution

RQ N/A

Chemical name EC2217A Supplier Nalco Ltd

Function Demulsifier Injection Point Subsea trees (P1 and P2)

Inlet to 1st stage separator


Limited demulsifier testing on the Solan crude (for well P1) indicated that crude/water emulsions may be readily broken through demulsifier addition after emulsion formation. EC2217A demulsifier is therefore injected at each wellhead to break any produced emulsions and limit viscous flow through the lines to the Solan platform. There is the requirement to initially fill the tank and then the chemical line. EC2217A will be applied to aid crude / water separation at P1 and P2, and in the future to production wells P3 and P4. Injection points are also used to apply the demulsifier at the inlet to the 1st stage separator. The demulsifier is continuously dosed at a concentration of 25 mg/L based on total produced fluids.

Produced water is not expected until 2016 2018 so demulsifier will not be required until then but contingency of 15,000 kg is requested for 2015 2016-2017 in case water is produced earlier than anticipated.

PLONOR HQ

category Gold


RQ

Year RQ

2015 N/A

2016 <1

2017 <1


Dosage 25 mg/l The product is applied at a dosage of 25 mg/L based on total produced fluid rates.


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Fraction discharged 100% A worst case discharge of 100% has been assumed during period of ballast water discharge.

CHARM algorithm code

PSO Discharge code CTN

Chemical name EC6004A Supplier Nalco Champion

Function Aromatic solvent Application point Downhole to production wells


EC6004A is used prior to start-up to flush the chemical injection lines prior to the injection of Asphaltene Inhibitor and Demulsifier. It will be batch injected downhole to production wells P1 and P2 in 2015. Contingency is requested for 2016.

The current fluid in the umbilical is incompatible with the asphaltene inhibitor and the demulsifier. This aromatic solvent is used in addition to the mutual solvent as a spacer fluid to displace the umbilical fluid to mitigate against any incompatibility issues. This is a one-time batch dose.

A batch size of 2477 kg is required to displace both the asphaltene and demulsifier cores in P1 and P2 wells.

PLONOR HQ

category Silver


RQ N/A

Justification:

EC6004A has a Silver HQ due to its high dosage rate on the HOCNF. The high dose rate associated with the HOCNF is to cover all usage possibilities if the chemical were required for a longer time frame. It is not likely to be toxic (worst case toxicity test results >100 mg/L).

Chemical name EC6527G Supplier Nalco Champion

Function Organic biocide Injection Point (1 of 5) Oil export line (downstream of the 2nd stage separator)


To assist in minimising the risk of bioactivity in the SOST, biocide EC6527G is injected downstream of the 2nd stage separator in the oil export line to the SOST when displacing oil in the tank for offloading.

The expected dose rate is 200 ppm (248 mg/l @ SG 1.24) based on the displaced oil rate.

A maximum batch size of 455 kg (2015) and 588 kg (2016) will be used.

PLONOR HQ

category Blue


RQ N/A

Justification:

Once the stock of this product has been used it will be replaced with the more environmentally friendly biocide EC6527H.

EC6527G has a blue HQ because of the high dosage rate (300 ppm) used on the CEFAS template coupled with its high toxicity (0.12 mg/L) and the fact that a standard production algorithm has been used to calculate the template. The worst case toxicity is high in order to fulfil its function as a biocide. As stated,


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this application uses a lower dosage than that used to generate the Cefas template.

Chemical name EC6527H Supplier Nalco Champion

Function Organic biocide Injection Point (1 of 5) Oil export line (downstream of the 2nd stage separator)


To assist in minimising the risk of bioactivity in the SOST, biocide EC6527H is injected downstream of the 2nd stage separator in the oil export line to the SOST when displacing oil in the tank for offloading.

The expected dose rate is 200 ppm (248 mg/l @ SG 1.24) based on the displaced oil rate.

A maximum batch size of 455 kg (2015) and 588 kg (2016) will be used.

PLONOR HQ

category Gold


RQ N/A


Function Biocide Injection Point (1 of 4) Oil export line (downstream of the 2nd stage separator)


To assist in minimising the risk of bioactivity in the SOST, biocide EC6718A is injected downstream of the 2nd stage separator in the oil export line to the SOST when required due to higher than expected water levels being routed to the SOST.

The expected dose rate is 500 ppm (550 mg/l @ SG 1.1) based on the produced water content in the crude oil from the outlet of the 2nd stage separator.

356.0 kg of EC6718A will be applied in 2016 and 546.7 kg in 2017.

PLONOR HQ

category Gold


RQ <1


Dosage 550 mg/l Worst-case dosage.

Fraction discharged 100% A worst case discharge of 100% has been assumed during ballast water discharge.

Batch dilution factor 7.46E-05 The batch dilution factor has been calculated as follows:

Density of fluid: 1.03

Volume discharged (set as high as possible): 120 m3

Discharge rate: 60 m3/hour

Batch Use 356.0 kg (2016) and 546.7 kg (2017)


CWS Discharge code BAT

Justification:


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EC6718A is a Glutaraldehyde / ABDAC (Benzyl-Dimethyl-Ammonium-Chloride) aqueous solution biocide. It is designed to effectively control and kill aerobic and anaerobic sulphate reducing bacteria expected in the production system and is effective against both sessile and planktonic species. EC6718A is specifically formulated to penetrate the biofilms of sessile bacteria. As there will be zero discharge of this product it is expected that there will be no impact to the marine environment.

EC6718A is a Gold category product that carries a UK National plan level 2 substitution warning. This is due to the quaternary ammonium surfactant component, which is present at less than 5% by weight. The level 2 substitution warning is assigned as this component is considered as toxic, bioaccumulating and moderately persistent. It is due to this toxicity that this is a suitable biocide for use within the SOST. The component generating the Gold HQ on the Cefas template comprises 46.8% of the product; although it is considered toxic, it is readily biodegradable.

EC6718A carries a substitution warning but considering its performance compared to industry standard, single component formulations, it is considered that this is the best possible option to protect the Solan SOST from the threat of microbiological influenced corrosion. There are non-SUB products (those without surfactants) available but these products do not provide the bio-penetration required in this application to combat biofilm which has the potential to be a significant problem in the SOST.


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Function Oil antifoam Injection Point 1st and 2nd stage separators


EC9242A is applied to the produced fluids in order to prevent oil/water foaming in the production separator. There is the requirement to initially fill the tank and then the chemical line. It will be injected continuously into the inlet to first stage separation and inlet to second stage separation.

This antifoam will be dosed into the produced fluids at 10 mg/L based on the produced oil rate. EC9242A has a relatively low density and a Log Pow of 2.42. Therefore the majority of the product would be expected to be separated off with the oil phase.

EC9242A is applied at 10 mg/l based on the produced oil rate. The 10 ppm stated for Solan is a worst case assumption based on a paper recommendation as no fluids were available at the time of the recommendation. The CEFAS template states a typical treatment rate and actual rates out on the platforms can differ due to operating conditions.

PLONOR HQ

category Gold


RQ N/A

Justification:

EC9242A has a SUB warning as the active ingredient is a silicone compound which is highly persistent biodegradation result <20% in 28 days). However, it is not likely to be toxic and a molecular weight > 700 so is not regarded as having any potential to bioaccumulate in marine species.

EC9242A has a relatively low density and a Log Pow of 2.42. Therefore the majority of the product would be expected to be separated off with the oil phase and be exported with the oil.

The manufacturer is aware that this product is a UK National Plan level 4 chemical and that it must be replaced, or discharges to the marine environment eliminated, or continued use and/or discharge must be formally justified by the end of December 2016. Currently there are no alternative products with the same classification that can replace, or eliminate the technical requirement for EC9242A.


Function Mutual solvent spacer Injection Point Downhole to production wells


EC9610A is used at start-up to flush the chemical injection lines prior to the injection of asphaltene inhibitor and demulsifier. It will be batch injected downhole to production wells P1 and P2 in 2015. Contingency is requested for 2016.

The current fluid within the umbilical is incompatible with the asphaltene inhibitor and the demulsifier. The mutual solvent (and the aromatic solvent) are used as spacer fluids to displace the umbilical fluid with the inhibitors without an incompatibility issues. They are one time batch doses.

A batch size of 826.2 kg is required to displace both the asphaltene and demulsifier cores in P1 and P2 wells.

PLONOR HQ

category Gold


RQ <1


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Dosage 511 mg/l Discharge dosage calculated from the batch use divided by the ballast water rates.






Batch Use 826.2 kg



Chemical name FX2443 Supplier Nalco Champion

Function Scale inhibitor Injection Point (1 of 2) Downhole to production wells


Calcium carbonate (CaCO3) scale formation, and a limited amount of barium sulphate (BaSO4) scale, is likely to occur in the producing wells throughout field life once water production commences. In order to prevent calcium carbonate scale precipitation in the produced water, scale inhibitor FX2443 is continuously applied downhole in all production wells (P1 and P2 currently and P3 and P4 in the future).

This scale inhibitor will be dosed into the produced fluids at 10 mg/L based on the produced water rate. Produced water is not expected until 2016 2018 so scale inhibitor will not be required until then but contingency of 500 kg is requested for 2015 2016-2017 in case water is produced earlier than anticipated.

PLONOR HQ

category Gold


RQ

Year RQ

2015 N/A

2016 N/A

2017 N/A


Dosage 10 mg/l The product is applied at a dosage of 10 mg/L based on the produced water rates.




Chemical name METHANOL (all grades) Supplier M-I SWACO

Function Gas Hydrate Inhibitor Injection Point Downhole to production Wells


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METHANOL (all grades) may be required to prevent formation of hydrates during start-up and production.

A batch size of 290 kg is required for this application.

This is not expected to have a significant impact on the marine environment as it is a small amount and this product is PLONOR and HQ Category E.

PLONOR HQ

category E


RQ N/A


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6.2 Seawater Treatment

Chemical name EC6198A Supplier Nalco Ltd

Function Biocide Application point Seawater Lift Pumps, Fire Pump, Skim Pump, Ballast Pumps and Seawater Displacement Pumps and water injection booster pumps.


EC6198A is used to prevent biological fouling within the seawater pumps used for Seawater Lift Pumps, Fire

Pump, Ballast Water Pumps, Seawater Displacement Pumps, and Skim Pump. Microbiological activity in

water systems can pose a corrosion risk, equipment fouling and the production of H2S gas.

The chemical is continuously dosed into the pumps (when running) at a maximum dosage of 50 ppm and will be discharged into the caisson and to sea. The product will be dosed prior to start up to cover the commissioning of the pumps and will continue until post start-up of the water injection system which will allow the in-situ Sodium Hypochlorite generation to function.

During the upcoming Solan Tanker Trial there is a requirement to commission the Solan Offloading system using treated seawater (containing EC6198A). This will be completed by using the displacement pumps and water injection booster pumps dosed with EC6198A to push water via the bypass line and also via the SOST to the tanker. This will result in 2,500 bbls of the SOST contents to be transferred to the tanker. This will then be taken to port where it will be discharged as slops. However, on completion of this trial there is a requirement to reduce the water levels in both the displaced water and ballast water caissons back to LAT to ensure the Solan SOST is not left under any form of static head pressure. During this operation Premier will pump a mixture of 1,000 bbls of the SOST contents and the treated seawater back to sea via the spill point on the ballast water caisson. Due to the nature of the SOST it is not possible know the exact mixture of the contents being discharged but this is assumed to be a 50/50 mix of treated seawater and the SOST contents. The SOST contents have already been previously discussed on page 9. It has been estimated that there will be an additional discharge of approximately 10 kg of Biocide from the treated seawater mix. An additional 2,644 kg of EC6198A is therefore required for this operation as a contingency to repeat the test three times using 881 kg per test. As a worst case 100% discharge has been assumed. This is not expected to have a significant impact on the marine environment as it is a small amount and this product is HQ Category E.

PLONOR HQ

category E


RQ N/A


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Function Oxygen scavenger Injection Point Deaerator tower


EC6213A is used to aid oxygen removal from the seawater used for re-injection. It will be continuously injected into the deaerator tower in order to reduce the oxygen content to <10 ppb.

The expected dose rate is 6 mg/l based on the seawater injection rate. During normal operation there is no direct overboard discharge as this chemical is used within the water injection system and is contained downhole. As a worst case 100% discharge has been assumed. This is not expected to have a significant impact on the marine environment as it is a small amount and this product is HQ Category E.

PLONOR HQ

category E


RQ N/A


Function Organic biocide Injection Point (2 of 5) Inlet to Seawater Displacement Caisson


EC6527G is required to inhibit marine growth within the seawater displacement water and will only be applied when displacing oil in the tank for offloading. It will be applied at 500 ppm (620 mg/l @ SG 1.24), based on the ballast water injected rate, for 2 hours every week. Therefore based on a ballast water injection rate of 800 m3 per day (using the high profile case and based on the average over field life), 41.33 kg of EC6527G will be applied in 2 hours.

PLONOR HQ

category Blue


RQ N/A

Justification:


EC6527G has a blue HQ because of the high dosage rate (300 ppm) used on the CEFAS template coupled with its high toxicity (0.12 mg/L) and the fact that a standard production algorithm has been used to calculate the template. The worst case toxicity is high in order to fulfil its function as a biocide.


Function Organic biocide Injection Point (2 of 5) Inlet to Seawater Displacement Caisson


EC6527H is required to inhibit marine growth within the seawater displacement water and will only be applied when displacing oil in the tank for offloading. It will be applied at 500 ppm (620 mg/l @ SG 1.24), based on the ballast water injected rate, for 2 hours every week. Therefore based on a ballast water injection rate of 800 m3 per day (using the high profile case and based on the average over field life), 41.33 kg of EC6527H will be applied in 2 hours.


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PLONOR HQ

category Gold


RQ N/A


Function Biocide Injection Point (2 of 4) Seawater Displacement Inlet Caisson


EC6718A is required to inhibit marine growth within the seawater displacement water and will only be applied when displacing oil in the tank for offloading. It will be applied at 500 ppm (550 mg/l @ SG 1.1), during every offload based on the displacement water rate. Offload is expected to occur every 14 days (as a maximum) and to take around 24 hours. Therefore based on displacement water rates provided in Table 5-1, 890 kg of EC6718A will be applied in 24 hours in 2016 and 1367 kg in 2017.

CHARM assessment of this chemical generated an RQ <1, indicating that the discharge is not expected to pose a significant risk to the surrounding marine environment.

PLONOR HQ

category Gold


RQ <1








Batch Use 890 kg (2016) and 1367 kg (2017)



Justification:

EC6718A is a Glutaraldehyde / ABDAC (Benzyl-Dimethyl-Ammonium-Chloride) aqueous solution biocide. It is designed to effectively control and kill aerobic and anaerobic sulphate reducing bacteria expected in the production system and is effective against both sessile and planktonic species. EC6718A is specifically formulated to penetrate the biofilms of sessile bacteria.

EC6718A is a Gold category product that carries a UK National plan level 2 substitution warning. This is due to the quaternary ammonium surfactant component, which is present at less than 5% by weight. The level 2 substitution warning is assigned as this component is considered as toxic, bioaccumulating and moderately persistent. The component generating the Gold HQ on the Cefas template comprises 46.8% of the product; although it is considered toxic, it is readily biodegradable.


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EC6718A carries a substitution warning but considering its performance compared to industry standard, single component formulations, it is considered that this is the best possible option to protect the Solan SOST from the threat of microbiological influenced corrosion. There are non-SUB products (those without surfactants) available but these products do not provide the bio-penetration required in this application to combat biofilm which has the potential to be a significant problem in the SOST.


Function Organic biocide Injection Point (13 of 35)

Seawater Displacement Inlet Caisson, Fire Pump Caisson, Seawater Disposal Caisson Skim Pump


There is a requirement for biocide dosing of the seawater prior to start up to maintain the integrity of the pump functions on return to the platform. A batch dose will be applied to the caissons every 3 months until start up to ensure integrity and prevent biofouling.

EC6527G will be applied in 55.86 kg batches in 2015 only. These caissons are open to the sea and as the biocide is heavier than water it is likely this will be discharged to sea. 100% discharge is expected and will be diluted with sea water prior to discharge. A dosage of 20.94 34.5 mg/l is calculated based on a ballast seawater rate of 2,667 1,618 m3/day. CHARM assessment of this chemical generated an RQ <1, indicating that the discharge is not expected to pose a significant risk to the surrounding marine environment.

PLONOR HQ

category Blue


RQ <1


Dosage 20.94 34.5 mg/l Worst-case assumed dosage Discharge dosage calculated from the batch use divided by the ballast water rates.

Fraction discharged 100% A worst case discharge of 100 % has been assumed.

Batch dilution factor 4.26E-04 7.45E-05 A batch dilution factor of 4.26E-04 7.45E-05 has been used as the overboard discharge rate is below the minimum values in CHARM:


Volume discharged (set as low as possible): 3 m3

(set as high as possible): 120 m3


Batch Use 55.86 kg



Justification:


EC6527G has a blue HQ because of the high dosage rate (300 ppm) used on the CEFAS template coupled with its high toxicity (0.12 mg/L) and the fact that a standard production algorithm has been used to


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calculate the template. The worst case toxicity is high in order to fulfil its function as a biocide. As stated, this application uses a lower dosage than that used to generate the Cefas template.



Seawater Displacement Inlet Caisson, Fire Pump Caisson, Seawater Disposal Caisson Skim Pump


There is a requirement for biocide dosing of the seawater prior to start up to maintain the integrity of the pump functions on return to the platform. A batch dose will be applied to the caissons every 3 months until start up to ensure integrity and prevent biofouling.

EC6527H will be applied in 55.86 kg batches. These caissons are open to the sea and as the biocide is heavier than water it is likely this will be discharged to sea. 100% discharge is expected and will be diluted with sea water prior to discharge. A dosage of 20.94 34.5 mg/l is calculated based on a ballast seawater rate of 2,667 1,618 m3/day. CHARM assessment of this chemical generated an RQ <1, indicating that the discharge is not expected to pose a significant risk to the surrounding marine environment.

PLONOR HQ

category Gold


RQ <1


Dosage 20.94 34.5 mg/l Worst-case assumed dosage Discharge dosage calculated from the batch use divided by the ballast water rates.


Batch dilution factor 4.26E-04 7.45E-05 A batch dilution factor of 4.26E-04 7.45E-05 has been used as the overboard discharge rate is below the minimum values in CHARM:


Volume discharged (set as low as possible): 3 m3

(set as high as possible): 120 m3


Batch Use 55.86 kg





Umbilical J-Tubes (J2, J4 & J5)



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There is a requirement for biocide dosing of the seawater within the J-Tubes to maintain the integrity of this sealed system. A batch dose will be applied to the three Umbilical J-Tubes, J2, J4 & J5 every month until start up to ensure integrity and prevent biofouling. J2 is currently not sealed and therefore will not be treated until post the subsea campaign in June where it will be sealed and then treated.

EC6527G will be dosed at 500 ppm (620 mg/l @ SG 1.24) into the top of the J-Tubes. EC6527G will be applied in 27.9 kg batches in 2015 only.

The seawater within the J-Tubes is sealed and will not be discharged to sea at any point.

PLONOR HQ

category Blue


RQ N/A

Justification:


EC6527G has a blue HQ because of the high dosage rate (300 ppm) used on the CEFAS template coupled with its high toxicity (0.12 mg/L) and the fact that a standard production algorithm has been used to calculate the template. The worst case toxicity is high in order to fulfil its function as a biocide. As stated, this application uses a lower dosage than that used to generate the Cefas template.



Umbilical J-Tubes (J2, J4 & J5)


There is a requirement for biocide dosing of the seawater within the J-Tubes to maintain the integrity of this sealed system. A batch dose will be applied to the three Umbilical J-Tubes, J2, J4 & J5 every month until start up to ensure integrity and prevent biofouling. J2 is currently not sealed and therefore will not be treated until post the subsea campaign in June where it will be sealed and then treated.

EC6527H will be dosed at 500 ppm (620 mg/l @ SG 1.24) into the top of the J-Tubes. EC6527H will be applied in 27.9 kg batches in 2015 only.

The seawater within the J-Tubes is sealed and will not be discharged to sea at any point.

PLONOR HQ

category Gold


RQ N/A


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Function Water antifoam Injection Point Deaerator tower


EC9029A is applied to the seawater used for re-injection in order to prevent water foaming. It will be injected continuously at the deaerator tower.

The expected dose rate is 5 mg/l based on the seawater injection rate. During normal operation there is no direct overboard discharge as this chemical is used within the water injection system and is contained downhole. As a worst case 100% discharge has been assumed. This CHARM assessment of this chemical generated an RQ <1, indicating that the discharge is not expected to pose a significant risk to the surrounding marine environment.

PLONOR HQ

category Gold


RQ <1


Dosage 5 mg/l The product is applied at a dosage of 5 mg/L based on the seawater injected rates.




Chemical name Sodium Hypochlorite Solution (generated in situ)

Supplier Generated in situ

Function Biocide Application point Seawater Lift Pumps, Fire Pump, Skim Pump, Ballast Pumps and Seawater Displacement Pumps and water injection booster pumps.


Sodium Hypochlorite is generated via electro-chlorinators and is used to prevent biological fouling within the seawater used for re-injection, Fire Water System, Platform Utilities and Cooling Water System. Microbiological activity in water systems can pose a corrosion risk, equipment fouling and the production of H2S gas. Sodium Hypochlorite will replace the use of EC6198A as soon as the electrochlorination unit is commissioned and ready for use.

The chemical is continuously dosed into the seawater lift pumps at 30 ppm and will be re-injected into the reservoir. As a worst case 100% discharge has been assumed. This is not expected to have a significant impact on the marine environment as it is a small amount and this product is HQ Category E.

PLONOR HQ

category E


RQ N/A


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6.3 Water Injection


Function Organic biocide Injection Point (5 of 5) Upstream of Water Injection


EC6527G is required to inhibit marine growth within the water injection fluids. A shock dose will be applied at 200 ppm (248 mg/l @ SG 1.24), based on the total water injected rate, for 2 hours every week. Therefore based on a water injection rate of 3,902 m3 per day (using the high profile case and based on the average over field life), 80.64 kg of EC6527G will be applied in 2 hours.

PLONOR HQ

category Blue


RQ N/A

Justification:




Function Organic biocide Injection Point (5 of 5) Upstream of Water Injection


EC6527H is required to inhibit marine growth within the water injection fluids. A shock dose will be applied at 200 ppm (248 mg/l @ SG 1.24), based on the total water injected rate, for 2 hours every week. Therefore based on a water injection rate of 3,902 m3 per day (using the high profile case and based on the average over field life), 80.64 kg of EC6527H will be applied in 2 hours.

PLONOR HQ

category Gold


RQ N/A


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Function Biocide Injection Point (3 of 4) Upstream of Water Injection


EC6718A is required to inhibit marine growth within the water injection fluids. A shock dose will be applied at 500 ppm (550 mg/l @ SG 1.1), based on the total water injected rate, for 2 hours twice every week. Therefore based on a ballast water injection rates provided in Table 5-1Error! Reference source not found., 74.2 kg of EC6718A will be applied in 2 hours in 2016 and 113.9 kg in 2017.


PLONOR HQ

category Gold


RQ <1








Batch Use 74.2 kg (2016) and 113.9kg (2017)



Justification:



EC6718A carries a substitution warning, but considering its performance compared to industry standard, single component formulations, it is considered that this is the best possible option to protect the Solan SOST from the threat of microbiological influenced corrosion. There are non-SUB products (those without surfactants) available but these products do not provide the bio-penetration required in this application to combat biofilm which has the potential to be a significant problem in the SOST.


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Chemical name FX2443 Supplier Nalco Champion

Function Scale inhibitor Injection Point (2 of 2) Water Injection – Upstream of produced water and seawater mixing point


In order to prevent scale precipitation when produced water and seawater mix, scale inhibitor FX2443 is applied upstream of where produced water and seawater mix before being injected downhole.

This scale inhibitor will be dosed into the injection fluids at 10 mg/L based on the produced water rate. Produced water is not expected until 2016 2018 so scale inhibitor will not be required until then but contingency of 500 kg is requested for 2015 2016-2017 in case water is produced earlier than anticipated.

PLONOR HQ

category Gold


RQ

Year RQ

2015 N/A

2016 <1

2017 <1


Dosage 10 mg/l The product is applied at a dosage of 10 mg/L based on the produced water rates.





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6.4 Drains


Function Biocide Injection Point (4 of 4) Closed drains


EC6718A is required to inhibit marine growth within the water injection fluids, including fluids from the drains. As the closed drains are routed via the 2nd stage separator the separator will also be treated by this application.

A shock dose will be applied at 500 ppm (550 mg/l @ SG 1.1), based on the closed drains vessel volume, every week. Therefore based on a closed drains vessel volume of 7.4 m3, 4.1 kg of EC6718A will be applied per batch.

PLONOR HQ

category Gold


RQ <1








Batch Use 4.1 kg



Justification:



EC6718A carries a substitution warning, but considering its performance compared to industry standard, single component formulations, it is considered that this is the best possible option to protect the Solan SOST from the threat of microbiological influenced corrosion. There are non-SUB products (those without surfactants) available but these products do not provide the bio-penetration required in this application to combat biofilm which has the potential to be a significant problem in the SOST.


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Function Organic biocide Injection Point (3 of 3) Open drains


EC6527G is required to inhibit marine growth within the water injection fluids, including fluids from the drains. As the open drains are routed to the ballast water caisson it is important to treat them to ensure that there is no transfer of microbial growth.

A shock dose will be applied at 500 ppm (620 mg/l @ SG 1.24), based on the open drains vessel volume, every week. Therefore based on an open drains vessel volume of 19.3 m3, 12 kg of EC6527G will be applied per batch.

Prior to water injection commissioning and during first fill of the SOST the open drains water will co-mingle with the ballast water then through the temporary filtration package and be discharged overboard via the seawater disposal caisson C-4801.


PLONOR HQ

category Gold


RQ <1


Dosage 0.00742 mg/l Discharge dosage calculated from the batch use divided by the ballast water rates.






Batch Use 12 kg



Justification:




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Function Organic biocide Injection Point (3 of 3) Open drains


EC6527H is required to inhibit marine growth within the water injection fluids, including fluids from the drains. As the open drains are routed to the ballast water caisson it is important to treat them to ensure that there is no transfer of microbial growth.

A shock dose will be applied at 500 ppm (620 mg/l @ SG 1.24), based on the open drains vessel volume, every week. Therefore based on an open drains vessel volume of 19.3 m3, 12 kg of EC6527H will be applied per batch.

Prior to water injection commissioning and during first fill of the SOST the open drains water will co-mingle with the ballast water then through the temporary filtration package and be discharged overboard via the seawater disposal caisson C-4801.


PLONOR HQ

category Gold


RQ <1


Dosage 0.00742 mg/l Discharge dosage calculated from the batch use divided by the ballast water rates.






Batch Use 12 kg




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6.5 Utility Chemicals

Chemical name Oceanic HW 443 Supplier Macdermid PLC

Function Hydraulic fluid Application Point Subsea controls


Oceanic HW 443 is a high performance water based hydraulic fluid for use in safety critical open and closed loop subsea control systems.

Small volumes of Oceanic HW 443 will be discharged to sea as the subsea valves are operated during commissioning and subsequent shutdowns. A worst-case maximum discharge of 15 83 L has been risk assessed, based on all valves opening during commissioning and any subsequent shutdowns of the P1, P2, W1 and W2 wells.

Osborne Adams modelling of a 15 83 L discharge results in T1>T2 therefore these small discharges are not expected to have a significant impact on the marine environment (see Section 6.6).

A worst-case discharge of 100% has been assumed, with the use over a 12-month period replacing the amount of chemical that has been discharged to sea.

PLONOR × HQ

category D


RQ N/A

Justification:

The substitution warning is triggered by a non-biodegradable fluorescent leak tracer dye at <150ppm in the whole product. The dye is not likely to be toxic and does not have the potential to bioaccumulate.

For over 15 years Oceanic HW 443 has proven its excellent technical performance and specified for use by equipment manufacturers. The product’s reliability in a safety critical application justifies its continued use.

The component responsible for the substitution warning is the leak tracer dye. Rapid detection and repair of leaks minimizes their environmental impact. The benefit of a fluorescent leak tracing dye outweighs the environmental impact. Oceanic HW443 is soluble in seawater and once discharged rapidly disperses below the no effect concentrations (NOEC) of all its components.

As alternative products are already available, the replacement schedule for Oceanic HW 443 is dictated by efforts to confirm that technical &/or safety issues will not be compromised. Therefore due to technical requirements this chemical is planned to be used until a new non-SUB product can fulfil the same role.


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Chemical name SOBO S GOLD 08 Supplier Oil Technics Ltd

Function Detergent / Cleaning Fluid

Application point Solan topsides


SOBO S Gold is a detergent/cleaning product used for general deck cleaning.

The chemical is applied as necessary to the decks at a dosage of 10,000 mg/l. This chemical will then be washed into the drainage system and be re-injected. Prior to drains commissioning all use will be captured and return to shore for disposal. As there will be zero discharge of SOBO S GOLD 08, its use is not expected to pose a significant risk to the marine environment. Prior to water injection commissioning and during first fill of the SOST the open drains water will co-mingle with the ballast water then through the temporary filtration package and be discharged overboard via the seawater disposal caisson C-4801.

PLONOR HQ

category Gold


RQ N/A


Dosage 10,000 mg/l Worst-case assumed dosage.

Fraction discharged

100% A worst case discharge of 100 % has been assumed.

Batch dilution factor

7.46E-05 The batch dilution factor has been calculated as follows:







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Chemical name ZOK 27 GS Supplier ZOK International Chemicals Limited

Function Detergent / Cleaning Fluid

Application point Turbines


ZOK 27 GS is a detergent/cleaning product used to clean the internals of the turbines. It is diluted at a ratio of 4:1 with water and is used in batches of 50 kg. The chemical is diluted, and then sprayed into the turbines to clean the internal machinery. This chemical will then mix with fluid in the drainage system and be re-injected. As there will be zero discharge of ZOK 27 GS, its use is not expected to pose a significant risk to the marine environment. Prior to water injection commissioning and during first fill of the SOST the open drains water will co-mingle with the ballast water then through the temporary filtration package and be discharged overboard via the seawater disposal caisson C-4801.

PLONOR HQ

category Gold


RQ N/A


Dosage 250,000 mg/l Worst-case dosage.









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6.6 Osborne Adams Calculations


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