a unique multifunctional foamer for deliquification of ......large hydrostatic caused by liquid...

Gas Well Deliquification Workshop

Sheraton Hotel, Denver, Colorado

February 19 – 22, 2012

A Unique Multifunctional Foamer for

Deliquification of Loaded Wells in

Canada

Duy Nguyen and Frank Cosman, Nalco Company

&

Richard Tomlins, Encana Corporation

Copyright 2012 Nalco Company & Encana Corporation. All rights reserved

Feb. 19 – 22, 2012 2012 Gas Well Deliquification Workshop

Denver, Colorado

2

Greater Sierra: Field Overview

• 800 Horizontal wells, 140 MMscfd

• Water gas ratio = 11-18 liters/1000m3 gas

• Condensate gas ratio = 5-15 liters/1000m3 gas

• Condensate water ratio = 0 to 2:1

• Salinity = 0 to 300,000 ppm

• Wet muskeg terrain, -40oC during the winter

094-I-15094-I-14094-I-13 094-I-16

094-I-10094-I-11 094-I-09094-I-12

094-I-07094-I-06094-I-05 094-I-08

094-I-03 094-I-02094-I-04 094-I-01

094-J-16

094-J-09

094-P-16094-P-13 094-P-15094-P-14

084-L-13

094-J-08

094-P-09094-P-11 094-P-10094-P-12

084-L-12

094-J-01

094-P-08094-P-07094-P-05 094-P-06

084-L-05

094-P-02094-P-04 094-P-01094-P-03

084-L-04

094-O-16

094-O-09

084-M-13

094-O-08

084-M-12

094-O-01

084-M-05

084-E-13

084-M-04

094-H-14094-H-13 094-H-15 094-H-16094-G-16

095-B-01 095-A-04 095-A-02 095-A-01095-A-03 085-D-04

094-J-15

094-J-10

094-J-07

094-J-02

094-O-15

094-O-10

094-O-07

094-O-02

094-G-15

095-B-02

084-L-14

084-L-11

084-L-06

084-L-03

084-M-14

084-M-11

084-M-06

084-E-14

084-M-03

085-D-03

084-E-12094-H-09094-H-11 094-H-10094-H-12094-G-09094-G-10 084-E-11

Petitot

Plant

D-061-

L/094-P-12

Midway

Plant

B-065-

B/094-P-04 Gunnell 1 &

2 Plant

B-023-F/094-

I-13

Sextet

Facility

B-067-J/094-

I-12 Elleh Plant

A-019-F/094-

I-12

Kyklo Plant

A-050-K/094-

I-11

Sierra Plants

1 & 2

A-026-K/094-

I-11

Infrastructure Legend

Encana Facilities

NG/SG Pipeline

Encana Sierra Assets

Northwest Territories

Alb

erta

Britis

h C

olu

mb

ia

Calgary

Edmonton

Grande Prairie

British Columbia

Alberta

Nature of Liquid Loading

Combination of factors:

• Reservoir depletion

• Water of condensation and formation water

• Liquid slugging

• Potential for static column of water in the

wellbore


Denver, Colorado

Deliquification Strategy

• Intermittent flow: Some wells may be shut in 75% of the

time in order

to build pressure to lift liquids.

• Plunger: Used in over 300 wells. Require additional

operator time and maintenance.

• Velocity strings: Used in over 200 wells. Difficulty handling

large hydrostatic caused by liquid slugs and are prone to

corrosion.

• Unsuccessful field trial of previous incumbent’s foamer in

2007 on 10 wells with capillary strings. The foamer could

not handle condensates.

• The use of foamers was revisited by Encana and Nalco in

2008 as Nalco had successfully used condensate foamers

with other gas producing companies.


Denver, Colorado

Advantages of Foamers

• Can be injected down the casing-tubing annulus

– much deeper than the plunger. However, to be

effective, the foamer has to reach and generate

foam at the end of the tubing, preventing

accumulation of liquids above the tubing.

• Low cost of the failure if the program proves to

be unsuccessful. The cost of failure for a foamer

is about $5,000 vs. $30,000 for a plunger lift

install or $75,000 for a velocity string install


Denver, Colorado

Foamer Development: Criteria for Success

• Effective in the presence of 50% condensate with

fresh water or brine

• Quick foam collapse at the well head

• A combination foamer product that contains

corrosion inhibitor and scale inhibitor

• Foamer is stable and pumpable at -43°C

• Foamer is compatible with HDPE, stainless steel,

and various elastomers


Denver, Colorado

Typical Surfactants • Nonionic :

– More soluble at lower temperature

– Increase temperature &/or salt concentration reduces solubility – lowers cloud point

– Good for wells with unknown water chemistry

• Anionic

– Excellent aqueous foamers

– Highly polar

– Can be affected by high brine solutions

– At elevated temperatures can degrade

• Cationic

– Good for foaming water/oil mixtures

– Efficacy dependant on molecular weight

– Can be prone to emulsion issues

• Amphotheric

– Very versatile : Higher condensate tolerance

– Good high temperature performance and stability

– Effective in high salt content brines

0

10

20

30

40

50

60

70

80

90

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

To

tal

Gra

ms C

arr

y O

ver

Time (minutes)

Impact of Salinity on Foaming Performance 50% condensate with 10000 ppm Foamer

5 scfh Nitrogen Flow Rate

Result: Foamer was effective in 50wt% condensate with chlorides > 4500 ppm

142 ppm Chloride 1500 ppm Chloride 4000 ppm Chloride

4500 ppm Chloride 12000 ppm Chloride 22000 ppm Chloride

32000 ppm Chloride

Laboratory Testing

NALCO’s Dynamic Unloading

Rig

Chloride

Foam Stabilizing: Area per molecule

Packing at the air-liquid interface

Air

Liquid

• Low salt

Unstable foam

Loosely packed film

- High area per molecule

Area

- - -

• High salt

Stable foam

- - - + + +

Air

Tightly packed film - Small area per molecule

Liquid

+ -


Denver, Colorado

Foam Destabilizing – Reduced Electrostatic Repulsion

- -

- - -

Stable foam

Low salt

Drainage

Liquid flows

Liquid flows

Unstable foam

High salt


Denver, Colorado

Laboratory Testing - Results

• Unloading efficiency results vary with

brine/condensate composition

• For all samples the amphoteric surfactant

showed greater potential for lifting fluids of

various concentrations when compared with

nonionic (alkyl poly glucoside) and anionic

(sulfossucinate, alkyldiphenyloxide

disulphonate) foamers

• Quick foam collapse was observed for the

amphoteric foamer

• Good separation for water and condensate (i.e.,

unstable emulsion) was observed


Denver, Colorado

Feb. 27 - Mar. 2, 2011 2011 Gas Well Deliquification Workshop Denver,

Colorado 12

Corrosion Inhibition: Linear Polarization Resistance Data

Decreased due to formation of

a protective film

Increased due to the breakdown of the film

Final 63 mpy

Final 0.06 mpy

Steep slope is an indication of a quick filmer

Gravimetric Results Sweet Conditions

Feb. 27 - Mar. 2, 2011 2011 Gas Well Deliquification Workshop Denver, Colorado

13

Blank

Treated

Corrosion Inhibition: Electrode

Photographs

Field Application: Wells Selection Criteria

• In 2009, eight (8) wells were identified for foamer applications based on the following criteria:

– A large database of LGR data.

– Multiple condensate and water analyses.

– Many years of production information and well pressure profiles.

– Operator experience with wells.

– Comparatively easy access to the well sites – a key requirement.

– Suitable well trajectory profile with no liquid trap before the end of the tubing

• Injection down casing on all wells


Denver, Colorado

• Initial results very encouraging

Status Well Production Uplift

(e3m3/d) Comment Forward Plan

#1 4.6 2nd Lowest WGR (15 l/e3m3), some condensate (2%)

#2 2.0 Highest WGR (96 l/e3m3),

no condensate

#3 1.5 2nd Highest WGR (68 l/e3m3), no condensate

#4 0.9 4th Highest WGR (48 l/e3m3), highest CLR (15%)

#5 0.8

#6 0.6

#7 2.1 3rd Highest WGR (51 l/e3m3), no condensate

#8 -1.2 Lowest WGR (8 l/e3m3),

no condensate, large water trap

Optimize soap injection rate downward

Optimize soap injection rate upward

Optimize soap injection rate upward. Capillary string candidates

Working (continuous flow)

Positive Response (long flow periods)

Not Working (no response to soap)

Summarry


Denver, Colorado

Soap Injection Summary

AFE Amount: $345k

Estimated Spend: $268K

Status Well On-Time Increase

(%)

Production Uplift

(e3m3/d) Injection Rate

(litres/d) Net Incremental Income

($/d)

1 50 to 100 1.9 4 162

2 33 to 100 1.6 4 130

3 26 to 99 1.2 4 88

4 38 to 100 0.8 1 75

5 39 to 79 1.2 5 78

6.7 18 533

6 31 to 60 0 4 -39

7 22 to 59 0.3 10 -66

0.3 14 -105

Dropped 8

Working

Marginal

Feb. 19 – 22, 2012 2012 Gas Well Deliquification Workshop Denver, Colorado

Results: Process Benefits

• No foam carryover in the vessels

• No emulsion issues noted

• Field trialled 8 wells in 2009; 38 wells in

2010; and began

37 more wells in 2011 with a success rate

of 70%

• Batch treat many other wells as needed


17

Challenges

• High condensate to water ratio

• Salinity varies from well to well (e.g., fresh water to nearly

saturated brine)

• Difficult to deliver foamer

into the horizontal section

due to liquid traps that occur

a short distance from the

horizontal section. There is

not enough energy to cause

foaming in that section and

the liquids cause a flow

restriction in the tubing or

open hole area.


18

1486

1488

1490

1492

1494

1496

1498

1500 1700 1900 2100 2300 2500 2700 2900 Measured Depth (MKB)

Vert

ical D

ep

th (

MK

B)

Open Hole TBG CSG

Liquid Trap

Way Forward

• Implement monitoring program to evaluate

performance of foamer’s corrosion inhibition

properties. If successful, significant cost

savings could be realized

• Ongoing expansion of foamer injection program

• Possible continuous injection through capillary

string installation to ensure the delivery of

foamer through the liquid traps

• Continued observation at the gas plant for

potential foaming issue as more wells will be on

foamer (today only about 7% of the wells are on

foamer)


19


Denver, Colorado

20

Copyright

Rights to this presentation are owned by the company(ies) and/or author(s) listed on the title page. By submitting this presentation to the Gas Well Deliquification Workshop, they grant to the Workshop, the Artificial Lift Research and Development Council (ALRDC), and the Southwestern Petroleum Short Course (SWPSC), rights to:

– Display the presentation at the Workshop.

– Place it on the www.alrdc.com web site, with access to the site to be as directed by the Workshop Steering Committee.

– Place it on a CD for distribution and/or sale as directed by the Workshop Steering Committee.

Other use of this presentation is prohibited without the expressed written permission of the author(s). The owner company(ies) and/or author(s) may publish this material in other journals or magazines if they refer to the Gas Well Deliquification Workshop where it was first presented.


Denver, Colorado

21

Disclaimer

The following disclaimer shall be included as the last page of a Technical Presentation or Continuing Education Course. A similar disclaimer is included on the front page of the Gas Well Deliquification Web Site.

The Artificial Lift Research and Development Council and its officers and trustees, and the Gas Well Deliquification Workshop Steering Committee members, and their supporting organizations and companies (here-in-after referred to as the Sponsoring Organizations), and the author(s) of this Technical Presentation or Continuing Education Training Course and their company(ies), provide this presentation and/or training material at the Gas Well Deliquification Workshop "as is" without any warranty of any kind, express or implied, as to the accuracy of the information or the products or services referred to by any presenter (in so far as such warranties may be excluded under any relevant law) and these members and their companies will not be liable for unlawful actions and any losses or damage that may result from use of any presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may be contained.

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a unique multifunctional foamer for deliquification of ......large hydrostatic caused by liquid...

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