innovations in reservoir surveillance dti perspective on reservoir surveillance colin cranfield...

Innovations in Reservoir Surveillance

DTI Perspective on Reservoir

SurveillanceColin Cranfield

Reservoir EngineerLicensing and Consents Unit

Aberdeen

15 September 2004


Quote from the late Laurie Dake*

Thorough data acquisition is expensive (very expensive) and it is the duty of practising reservoir engineers to convince those who hold the purse strings of the necessity of the exercise.

* “The Practice of Reservoir Engineering”


Overview

• DTI-LCU remit– PILOT initiatives

• UKCS reserves– Brown field growth

• Reservoir surveillance– General issues– Field observations

• Conclusions


DTI-LCU aim

• Maximise economic recovery of UK oil & gas– while minimising environmental

impact


Reservoir surveillance is important throughout field life

• Need to establish economic viability of reservoir, .e.g EWTs• Gain reservoir understanding for effective management• Establish that reservoir is uneconomic prior to abandonment

Field determination

issued

FDP approved

Field start-up

COP

AFRs submitted / Addenda to FDP

Pre-development discussions

Phased development ?


PILOT targets

• Government – industry partnership– Striving to meet 2010 target


PILOT targets

• Government – industry partnership– Striving to meet 2010 target

• Can only be achieved via– New field development– Brown field growth– Exploration success


UK production forecast (mmboe/d)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Possible new developments

Probable new developments upside

Brown field growth

Probable new developments

Approved fields Proven + Probable

Actual production Forecast UKCS oil and gas production 2003 - 2010

Source DTI 2003 annual reserves review

PILOT targets 2005 & 2010


DTI initiatives

• PILOT– Fallow process– Promote licences– Access to data– Infrastructure code of practice– Brown field work group

• Plus– Work with ITF on technology development– IOR conferences, web sites, eNewsletter


UKCS recovery factor distribution

Northern North SeaOil Recovery 43%

(upside 45%)

Southern North SeaGas Recovery 74%

(upside 78%)

-

Source DTI

Central North Sea Oil Recovery 46%

(upside 49%) Gas Recovery 65%

(upside 71%)

Key

Oil Gas

Production to date

P+P Reserves

Possible reserves

Unrecovered


Improving brown field recovery

Reserves % increase 1991 - 2003

0

10

20

30

40

50

60

70

80

90

Source UK Oil & Gas Commemorative Volumes


Brown field growth

• Brown field WG addressing barriers• Typical success factors

– Cost control– Combining technologies

• Technological advances• Drilling & completion

– Geo-steering• Sub-sea tie-back

• Improved reservoir understanding• Integrated approach• 3D/4D advances


By-passed & trapped oil

• Causes– Reservoir compartmentalisation– Fault shadows– Heterogeneity– Attics

• Opportunities– Better utilise injection– Infill / sidetrack locations– Well work / re-perforation / water or gas shut-

off


1) Existing wells draining effectively?



Existing B2 perforations 10383 – 10423 ft mdUn-perforated 10423 – 10470 ft mdExisting B2 perforations 10478 – 10498 ft md

Massive sands – un-perforated intervals



Un-perforated interval 11,770 – 11,790 ft md

Channel sands – un-perforated interval



Gamma ray spikes – could they be horizontal barriers?


Typical surveillance approaches• Routine

– RFT, LWD, logging– Production performance

• Non-routine– 3D/4D, geochem, geomech, SrRSA

• Permanent surveillance• Difficulty in estimating value

– More advanced cost/benefit analysis?


Andrew production & 4D surveys

-

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

110,000

120,000

130,000

140,000

150,000

Jun

-96

Se

p-9

6

De

c-9

6

Ma

r-9

7

Jun

-97

Se

p-9

7

De

c-9

7

Ma

r-9

8

Jul-

98

Oct

-98

Jan

-99

Ap

r-9

9

Jul-

99

Oct

-99

Jan

-00

Ap

r-0

0

Jul-

00

No

v-0

0

Fe

b-0

1

Ma

y-0

1

Au

g-0

1

No

v-0

1

Fe

b-0

2

Ma

y-0

2

Au

g-0

2

De

c-0

2

Ma

r-0

3

Jun

-03

Se

p-0

3

De

c-0

3

Flu

id [

bb

ls/d

]

-

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

110,000

120,000

130,000

140,000

150,000

Ga

s [

ms

cf/

d]

Daily Water Volume bbl

Daily Oil Volume plbbl

Daily Gas Production

Baseline3D

2001 2002 20043D/4D Survey acquisition

MaximisingBrown fieldRecovery

OIL Rate

Water Rate


Surveillance challenges – past and present

• Compartmentalisation– Impacted injection strategies

• Hydraulic fracturing– Poorly controlled water injection

• Marginal / sub-sea developments– Pre-drilled wells

• Based on static data• Non-optimum well placement

– Defer injection wells?• Inaccurate zonal allocation

– Inability to model reservoir


UKCS reserves categorised by development type

Source DTI web page

Platform Fields

Subsea tiebacks

Undeveloped

UKCS reserves

20 billion boe

Key

Developed P+P

Developed Fields Possible

SST P+P

SST Possible

Undeveloped Probable

Undeveloped Possible

Potential Additional

FPFs/FPSOs


Way forward - reservoir surveillance

• Continue to refine and improve surveillance– Down-hole flow- & pressure-meters

• By zone

• Continue to integrate data observations– More sophisticated analysis

• Tailor strategy to specific reservoir situation– Address key uncertainties

• Develop case for thorough data acquisition


For DTI oil & gas information:

http://www.og.dti.gov.uk/

or contact:

[email protected] 254066

Thank you for listening

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