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WTA3 report

Welltest interpretation reportAnalysis name : Leaky Fault

Company : Hydrocarbon Theater CompanyField :Moliere

Test type : StandardTest Name / # : DST 3

TABLE OF CONTENTS

A01 Main results

A02 Introduction

B01 QA/QC

B02 Interpretation

B03 Results

C01 Conclusions

Appendices:

App 01 Saphir report

A01 Main results

Dst 3 tested the Tartufian formation over the perforated interval 1127-1138 m BRT after an acid job to assess the efficiency of the operation.The well test consisted of two main periods:

A clean up period followed by two main production periods at increasing rate A conventional build-up.

A production period on reduced choke to take fluid samples

The build-up analysis yields the well and reservoir characteristics and the pressure response of the build-up indicates the possibility of a mobility barrier close to the well.

During the clean-up and main flow a slowly improving skin was observed. This is believed to be migration of residuals resulting from the acid effect.

The main interpretation results are listed below:

Permeability thickness, kh

2520 md.ft Permeability, k

74 md Total skin, S

-3.73 Pi at gauge depth (1,093.41 m BRT)

3597.35 psia PI (productivity index)

4.69564 [STB/D]/psia Distance to a possible fault

287 ftA02 Introduction

Dst 3 tested the Tartufian formation over the perforated interval 1127-1138 m BRTThe well test consisted of three periods:

The clean up and main flow period started at 00:00 and 15:00 on 16/02/2001 the well was producing at surface. During the clean-up the PCT closed for a short time due to some surface technical problems, however the flow was continued on a 48/64 choke and final average rate of some 2300 stb/d oil with a gravity of 21 API and a 450 cf/bbl GOR. A 12-hour build-up followed the main flow. The well was then open for bottom hole sampling, and two samples caught while flowing on a 32/64 choke, then 16/64.

Fig. 1: Pressure and flowrates

None of the flowing periods could be analyzed due to fluctuations in the flowrates.

B01 QA/QC

Four pressure gauges were run in two bundle carriers. The gauges SLSR 767 and 921 with sensing points at 1,107.81 m BRT and gauges 1206 and 785 with a sensing depth of 1,093.41 m BRT, some 51.6 m above top of sandface. Fig. 2 illustrates the pressure sequence during the test.

Bottom hole pressure history

Four pressure gauges were run in two bundle carriers. The upper pressure gauge pair (1206 and 785) was set with sensing points at 1,093.41 m BRT. The lower gauges (767 and 921) with their sensing point at 1,107.81 m BRT. The gauge 921 was used in the analysis.

The accuracy off-set between gauge 1206 and 785 assumed to be at the same sensing depth of 1,093.41 m BRT was evaluated to 0.34 psia, satisfactory for these types of gauges.

The off-set between 921 and 1206 at 12.41 psi is consistent with the expected liquid pressure gradient.

A drift is observed on the gauge 767 data compared to the other gauges and this gauge will not be kept for analysis purpose.The gauge 921 was kept for the analysis for its satisfactory behaviour and accuracy and also as the deepest correct gauge.

B02 Interpretation

The interpretation was performed on the main build-up.The very negative skin (-3.73 ) demonsrates immediately the efficiency of the acid job.

A model for a well in an homogeneous infinite reservoir was first used, but the derivative, slighty increasing, then decreasing at the end of the build-up, suggested the effect of a mobility barrier. A model of leaky fault was chosen, in agreement with the information given by the geology including the possibility of a fault around 100 meters from the well.

The pressure and production history plot shows clearly the improving skin during the first two production periods, where the pressure drawdown tends to stabilize faster than the simulation.B03 Results

The detail of the results is given in the table below:

NameValue

Main Model Parameters

C0.00299 bbl/psi

Total Skin-3.73

k.h, total2520 md.ft

k, average74 md

Pi3597.35 psia

Model Parameters

Well & Wellbore parameters (Moliere 1)

C0.00299 bbl/psi

Skin-3.73

Reservoir & Boundary parameters

Pi3597.35 psia

k.h2520 md.ft

k74 md

L287 ft

Leakage0.507397

Derived & Secondary Parameters

Prod. Index4.50336 [STB/D]/psia

Rinv1780 ft

Test. Vol.0.0407057 bcf

Delta P (Total Skin)-348.959 psi

Delta P Ratio (Total Skin)-0.762749 Fraction

.

C01 Conclusions

The DST 3 was successfully completed. The analysis yielded a stabilized skin of -3.73 revealing an efficient well stimulation.Evidence of one mobility barrier (here treated as leaky fault at 287 ft) was identified in the test data. The interpreter could justify the use of this model by the possibility of a non totally sealing fault in the vicinity of the well suspected by the geology.

The productivity of the well was calculated to 4.69564 [STB/D]/psia and, compared to the initial PI value (1.8 [STB/D]/psia ) calculated from the DST 2, it significantly increased during the stimulation job.

Complete table of inputs and resultsNameValueNameValue

Test date / time16/02/2001 Main Model Parameters

Formation intervalTartufian C0.00299 bbl/psi

Perforated interval1127-1138 m BRT Total Skin-3.73

Gauge type / # k.h, total2520 md.ft

Gauge depth1050 m k, average74 md

Pi3597.35 psia

TEST TYPEStandard

Model Parameters

Porosity Phi (%)12 Well & Wellbore parameters (Moliere 1)

Well Radius rw0.29 ftC0.00299 bbl/psi

Pay Zone h34 ftSkin-3.73

Reservoir & Boundary parameters

Form. compr.3E-6 psi-1Pi3597.35 psia

k.h2520 md.ft

FLUID TYPEOil k74 md

L287 ft

Volume Factor B1.25 B/STBLeakage0.507397

Viscosity0.58 cp

Total Compr. ct3E-6 psi-1Derived & Secondary Parameters

Prod. Index4.50336 [STB/D]/psia

Selected Model Rinv1780 ft

Model OptionStandard Model Test. Vol.0.0407057 bcf

WellVertical Delta P (Total Skin)-348.959 psi

ReservoirHomogeneous Delta P Ratio (Total Skin)-0.762749 Fraction

BoundaryLeaky fault

NameValueNameValue

Gauge 1 build-up #1

Rate0 STB/DModel Parameters

Rate change2300 STB/DWell & Wellbore parameters (Moliere 1)

P@dt=03086.62 psiaC0.00299 bbl/psi

Pi3597.35 psiaSkin-3.73

Smoothing0.1 Reservoir & Boundary parameters

Prod. Index4.50336 [STB/D]/psiaPi3597.35 psia

k.h2520 md.ft

Selected Model k74 md

Model OptionStandard Model L287 ft

WellVertical Leakage0.507397

ReservoirHomogeneous

BoundaryLeaky fault Derived & Secondary Parameters

Prod. Index4.50336 [STB/D]/psia

Main Model Parameters Rinv1780 ft

C0.00299 bbl/psiTest. Vol.0.0407057 bcf

Total Skin-3.73 Delta P (Total Skin)-348.959 psi

k.h, total2520 md.ftDelta P Ratio (Total Skin)-0.762749 Fraction

k, average74 md

Pi3597.35 psia

NameValueNameValue

Gauge 1 build-up #1 Pi3597.35 psia

Rate0 STB/Dk.h2520 md.ft

Rate change2300 STB/Dk74 md

P@dt=03086.62 psiaL287 ft

Pi3597.35 psiaLeakage0.507397

Smoothing0.1

Prod. Index4.50336 [STB/D]/psiaDerived & Secondary Parameters

Prod. Index4.50336 [STB/D]/psia

Selected Model Rinv1780 ft

Model OptionStandard Model Test. Vol.0.0407057 bcf

WellVertical Delta P (Total Skin)-348.959 psi

ReservoirHomogeneous Delta P Ratio (Total Skin)-0.762749 Fraction

BoundaryLeaky fault

Semilog Line (Gauge 1 build-up #1)

Main Model Parameters From26.1694 hr

C0.00299 bbl/psiTo26.2194 hr

Total Skin-3.73 Slope113.899 psi

k.h, total2520 md.ftIntercept3576.44 psia

k, average74 mdP@1hr3425.66 psia

Pi3597.35 psiak.h2380 md.ft

k70 md

Model Parameters p*3576.44 psia

Well & Wellbore parameters (Moliere 1) Skin-3.88

C0.00299 bbl/psiDelta P Skin-384.326 psi

Skin-3.73

Reservoir & Boundary parameters

NameValueNameValue

Gauge 1 build-up #1 Pi3597.35 psia

Rate0 STB/Dk.h2520 md.ft

Rate change2300 STB/Dk74 md

P@dt=03086.62 psiaL287 ft

Pi3597.35 psiaLeakage0.507397

Smoothing0.1

Prod. Index4.50336 [STB/D]/psiaDerived & Secondary Parameters

Prod. Index4.50336 [STB/D]/psia

Selected Model Rinv1780 ft

Model OptionStandard Model Test. Vol.0.0407057 bcf

WellVertical Delta P (Total Skin)-348.959 psi

ReservoirHomogeneous Delta P Ratio (Total Skin)-0.762749 Fraction

BoundaryLeaky fault

Semilog Line (Gauge 1 build-up #1)

Main Model Parameters From26.1694 hr

C0.00299 bbl/psiTo26.2194 hr

Total Skin-3.73 Slope113.899 psi

k.h, total2520 md.ftIntercept3576.44 psia

k, average74 mdP@1hr3425.66 psia

Pi3597.35 psiak.h2380 md.ft

k70 md

Model Parameters p*3576.44 psia

Well & Wellbore parameters (Moliere 1) Skin-3.88

C0.00299 bbl/psiDelta P Skin-384.326 psi

Skin-3.73

Reservoir & Boundary parameters

Appendix 1

Saphir report

Complete table of results

QAQC plot

History