+ All Categories
Home > Documents > DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large...

DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large...

Date post: 28-Dec-2015
Category:
Upload: kathryn-powell
View: 216 times
Download: 1 times
Share this document with a friend
Popular Tags:
13
DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia) Sebastien Perrier, Tomi Sugiarto, TOTAL E&P INDONESIE European and West African Perforating Symposium 2012
Transcript
Page 1: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN

CONVENTIONAL PERFORATIONS

A large scale comparative review from the Tunu Gas Field (Indonesia)

Sebastien Perrier, Tomi Sugiarto, TOTAL E&P INDONESIE

European and West African Perforating Symposium 2012

Page 2: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

0

1000

2000

3000

4000

5000

High Pressure Belly

>=1.20sg

Fluviatil channelDistributary channelMouth bar

Gas

SU1

Tunu

Mai

n

Zone

Tunu

Sha

llow

SU2

SU3

SU4

SU5

SU6

Fresh Water Sand

MFA

MFB

MF0

MF1

MF1.5MF2

Intra-beta

ESEWNW

Very Shallow

mssTubingless completions

Perforations are added

by light intervention barges (electric lines)

Multilayer thin sandstone Reservoirs

Gas + condensate

Deltaic channelsand mouth bars

10-20% Porosity1-500md Permeability

• What is the TUNU field (Indonesia, PSC Mahakam)?

• Annually: more than 2500 ms of perforations, 600 intervals

• Large activities and workload continue to increase as field become mature• Sufficient data for developing comprehensive perforation analysis

Page 3: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

WHAT IS “DYNAMIC UNDERBALANCE” (DUB)?

Dynamic Underbalance (DUB) TechnologyDynamic Underbalance (DUB) Technology• Generate a large dynamic under balance from modest static under

balanced or over balanced pressure.

• DUB system needs set of charges and additional void space inside the gun (blank section, implosive chamber).

• DUB system required liquid (water / oil / mud) around the gun when shot.• Fast gauge is run in tandem with the gun to measure actual dynamic

underbalance (optional, record up to 100,000 samples/second)

Unload using coiled tubing and nitrogen

FiredFired

0.05 seconds

Result: pressure drop within perforation intervals by 1500 to 2500 psi during a few milliseconds Objective: optimized clean up of the perforation cavity

Page 4: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

DOES IT WORK?

Legend in this presentation:Conventional perforations, without DUBPerforations with Dynamic UnderBalance

Data from TUNU gas field (2005-2011), operated by TOTAL EP INDONESIE

Perforation results, by classes of gain(mmscfd per job)

0%5%

10%15%20%25%30%35%40%45%50%

No/Weak flow

2-5 5-10 10-15 15-20 20+Perforation gains (mmscfd)

Perforation initial production rates 2005-2011( one reservoir only per job)

Conv.Perfos

Dynamic UB

Productivity by meter of perforation(mmscfd / m)

0%5%

10%15%20%25%30%35%40%

< 1 1 - 3 3 - 5 5 - 8 8 - 10 > 10

%

Perforation Gain per Meter of Net Pay(mmscfd/m)

Reservoir productivityVirgin pressure reservoirs only

Conv.Perfos (100 res.)Dynamic UB (23 res.)

Page 5: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

ARE WE SURE THERE IS NO BIAS?

There are always some classical bias• Choice/selection of best reservoirs for application of DUB? “Quality bias”?• ~30 DUB perforations only: “luck” effect ?

The question becomes: “once we remove quality bias and adjust for the sample size,

will DUB still make a difference?”

0%

5%

10%

15%

20%

25%

<9% 9-10% 10-11%

11-12%

12-13%

13-14%

14-15%

15-16%

16-17%

17%+

PorosityDynamic Underbalance perforationsFull Sample Conventionnal Perfos

It is a fact that reservoirs perforated with DUB in Tunu tend to have better petrophysical properties on average

Porosity classes

Example of petrophysical indicator : Porosity

Page 6: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

Participants’ guess(average)

Real result

Conv. perfos 2,0 / 6 2,1 / 6

Dynamic UB 2,4 / 6 2,8 / 6

FIRST METHOD: A POLL (13 INNOCENT PAIRS OF EYES)!

Poll with 13 engineers/Geologists familiar with the Field:

• Random sets of 50 reservoirs , with all the data used by “Tunu field” practitioners

• 15 random reservoirs perforated with DUB dissimulated in each set

1 question: “for each reservoir, which perfo. gain (in mmscfd) do you expect?”

Gain <2 2-5 5-10 10-15 15-20 >20

Mark 1 2 3 4 5 6

(MMscfd)

Page 7: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

SECOND METHOD: USING EPIDEMIOLOGICAL METHODSEpidemiological methods = classically used to test new drugs or health issues

1.Which steps?

• Validation of data quality is essential• Perforations without a clear outcome are not considered

No perforation job with multi reservoirsReservoirs diagnosed with technical problems or water problems are excludedNeed to have reliable pressure data (cf infill wells)

• The statistical influence of each parameter on differences between results using the same perforation technique must be understood before any comparison– Degree of dependence between parameters– Influence of porosity, res. pressure, etc…– gun size, static underbalance, brand, etc…

(cf. SPE paper 158083 for extensive details)

Increasing porosity

Pro

b. o

f flo

w

Page 8: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

SECOND METHOD: USING EPIDEMIOLOGICAL METHODS

Epidemiological methods = classically used to test new drugs or health issues

• The challenge: Build “comparable samples”, free of size and quality bias• More than 200 eligible conventional perforations

• 29 flowing DUB perforations

• Two possible approachs: • Our original approach

– Our group of 29 DUB perfo is the reference sample

– Let’s downscale the 200 conv. perforations into random draws of 29 representatives, respecting same res. characteristics as DUB samples

To get an apple to apple comparison, let’ s try a comparison between

“Basket filled with 29 apples” and “baskets with 29 apples ”!

Page 9: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

RANDOM GENERATION OF 150 COMBINATIONS OF 27-30 CONV.PERFOS, WITH SAME RESERVOIR PROPERTIES AS DUB SAMPLE

0%

5%

10%

15%

20%

25%

30%

35%

<9% 9-10% 10-11% 11-12% 12-13% 13-14% 14-15% 15-16% 16-18% 18%+

Porosity

P90 to P100P50 to P90P10 to P50P0 to P10""Dynamic UBFull Sample Conv. Perfos

0%

10%

20%

30%

40%

50%

60%

70%

Mobility

0%

10%

20%

30%

40%

50%

60%

Net Pay Thickness

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

<0

.3

0.3

-0.5

0.5

-0.7

0.7

-0.9

0,9

+

NA

Pressure (deq)Only MDT data valid (less than 1 yr)DUB

Percentiles of sub-samples distribution

Sub-samples randomly created, but “matching” DUB sample distributions of porosity, pressure, mobility, and thickness

Page 10: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

RESULT: AN EXPLICIT INSIGHT IN THE PERFORATION RESULTS

Distribution of Results (in mmscfd/m) of the 150 randomly created sub-samples of conventional perforations

At 90% confidence level: Dynamic UB does bring better productivity results than conv. perfos

3.0P10

3.7P90

3.4 MODE

Dynamic UBSample : 4mmscfd/m

Confidence interval at 90%for DUB estimator:

3,7 – 4,3

Explicit evaluation of benefit = +10 to +25% initial productivity (3.7-4.3 vs 3.4)

Page 11: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

CONCLUSIONSIn Tunu gas sandstones, Dynamic UnderBalance makes a difference+10 to +25% initial productivity per meter of perforation

after removing all possible statistical bias (reservoir quality & sample sizes)

10 additionnal jobs performed post-study reinforce the quantitative resultsThey still give 4.0mmscfd/d, with similar quality

Applicability?

– In gas wells, DUB is limited to wells with a liquid column (provider)– Unlikely adapted for tighest reservoirs (operator’s observation)

• Why not having worked with evaluations of “skin” ?

– Too little data to be analysed (see paper)– Skin data validity and quality are a major variable, with little control, as associated to well

testing procedures

• Independent analysis, and more in SPE158083

Page 12: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

AcknowledgementsTotal E&P Indonesie

INPEX

BPMigas - MIGAS

Thank You / QuestionsPaper # • Paper Title • Presenter Name

Slide 12

Page 13: DYNAMIC UNDERBALANCE PERFORATIONS BRING HIGHER PRODUCTIVITIES THAN CONVENTIONAL PERFORATIONS A large scale comparative review from the Tunu Gas Field (Indonesia)

EWAPS 2012

DYNAMIC UNDERBALANCE SUCCESS

Technique Design gun to get optimum dynamic underbalance Design 100psi static UB and estimate the reservoir pressure is enough to lift up the fluid column Clean up the well right after perforation, CT ready to start up in case well unable to flow RIH fast gauge tandem with gun to measure the dynamic underbalance

Gun Type 2.5” PJO 2506 estimated DUB at bottom gauge: 1560 psi real DUB at bottom gauge was 1620 psi

Completion Data Casing Size: 3.5” (9.2ppf) Min restriction: 2.81” Brine in borehole (1.03 sg) BHP=5120 psi

Reservoir Data Porosity: 12.95% Pore Pressure: 5211 psi Mobility: 31.6 Interval 3620.5-3623.5m (3m reservoir P131)

Result Real DUB at bottom gauge: 1620psi (fast gauge data) Well flow 15.9 MMscfd without unloading job


Recommended