Saphir Sample Report

Welltest interpretation reportAnalysis name : KVar_InputParam_73

Company : KVar_InputParam_1 Field :KVar_InputParam_2

Test type : KVar_InputParam_10Test Name / # : KVar_InputParam_4

Well 1

Well Test Interpretation

DST 3

(1127-1138 m BRT)

Formation Tartufian




TABLE OF CONTENTS

A01 • Main resultsA02 • Introduction

B01 • QA/QCB02 • InterpretationB03 • Results

C01 • Conclusions

Appendices:

App 01 • Saphir report




A01 • Main results

Dst 3 tested the Tartufian formation over the perforated interval KVar_InputParam_7 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 KVar_ResBound_1_33 Permeability, k KVar_ResBound_1_32 Total skin, S KVar_Well_1_1_6 Pi at gauge depth (1,093.41 m BRT) KVar_ResBound_1_31 PI (productivity index) KVar_SemiLog_15 Distance to a possible fault KVar_ResBound_1_22




A02 • Introduction

Dst 3 tested the Tartufian formation over the perforated interval KVar_InputParam_7

The well test consisted of three periods:

The clean up and main flow period started at 00:00 and 15:00 on KVar_InputParam_5 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 21º 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

3200

3400

3600

3800

4000

0 5 10 15 20 25 30 35 40 45 50

0

1000

2000

History plot (Pressure [psia], Liquid Rate [STB/D] vs Time [hr])

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

3200

3400

3600

3800

4000

Pre

ssu

re [

psia

]

0

10

Pre

ssu

re (

dif

fere

nce

) [p

si]

0 10 20 30 40 50

Pressure [psia], Pressure [psi] vs Time [hr]

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 (KVar_Well_1_1_6) 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.

1E-3 0.01 0.1 1 101

10

100

Log-Log plot: dp and dp' [psi] vs dt [hr]

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:

Name Value

Main Model Parameters

C 0.00299 bbl/psi

Total Skin -3.73

k.h, total 2520 md.ft

k, average 74 md

Pi 3597.35 psia

Model Parameters Well & Wellbore parameters (Moliere 1)

C 0.00299 bbl/psi

Skin -3.73 Reservoir & Boundary parameters

Pi 3597.35 psia

k.h 2520 md.ft

k 74 md

L 287 ft

Leakage 0.507397

Derived & Secondary Parameters

Prod. Index 4.50336 [STB/D]/psia

Rinv 1780 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 KVar_Well_1_1_6revealing an efficient well stimulation.Evidence of one mobility barrier (here treated as leaky fault at KVar_ResBound_1_22) 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 KVar_SemiLog_15 and, compared to the initial PI value (1.8 [STB/D]/psia ) calculated from the DST 2, it significantly increased during the stimulation job.




Appendix 1

Saphir report

Complete table of results QAQC plot History plot Log log plot Semilog plot




Complete table of inputs and results

SaphirRes_MainResults Value Name Value

Test date / time 16/02/2001 Main Model Parameters

Formation interval Tartufian C 0.00299 bbl/psi

Perforated interval 1127-1138 m BRT Total Skin -3.73

Gauge type / # k.h, total 2520 md.ft

Gauge depth 1050 m k, average 74 md

Pi 3597.35 psia

TEST TYPE Standard

Model Parameters

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

Well Radius rw 0.29 ft C 0.00299 bbl/psi

Pay Zone h 34 ft Skin -3.73

Reservoir & Boundary parameters

Form. compr. 3E-6 psi-1 Pi 3597.35 psia

k.h 2520 md.ft

FLUID TYPE Oil k 74 md

L 287 ft

Volume Factor B 1.25 B/STB Leakage 0.507397

Viscosity 0.58 cp

Total Compr. ct 3E-6 psi-1Derived & Secondary Parameters


Selected Model Rinv 1780 ft

Model Option Standard Model Test. Vol. 0.0407057 bcf

Well Vertical Delta P (Total Skin) -348.959 psi

Reservoir Homogeneous Delta P Ratio (Total Skin) -0.762749 Fraction

Boundary Leaky fault




3200

3400

3600

3800

4000

Pre

ssu

re [

psia

]

0

10

Pre

ssu

re (

dif

fere

nce

) [p

si]

0 10 20 30 40 50

Pressure [psia], Pressure [psi] vs Time [hr]




3200

3400

3600

3800

4000

0 5 10 15 20 25 30 35 40 45 50

0

1000

2000

History plot (Pressure [psia], Liquid Rate [STB/D] vs Time [hr])

SaphirRes_Historyplot Value Name Value

Gauge 1 build-up #1

Rate 0 STB/D Model Parameters

Rate change 2300 STB/DWell & Wellbore parameters (Moliere 1)

P@dt=0 3086.62 psia C 0.00299 bbl/psi

Pi 3597.35 psia Skin -3.73

Smoothing 0.1 Reservoir & Boundary parameters

Prod. Index 4.50336 [STB/D]/psia Pi 3597.35 psia

k.h 2520 md.ft

Selected Model k 74 md

Model Option Standard Model L 287 ft

Well Vertical Leakage 0.507397

Reservoir Homogeneous

Boundary Leaky fault Derived & Secondary Parameters


Main Model Parameters Rinv 1780 ft

C 0.00299 bbl/psi Test. Vol. 0.0407057 bcf

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

k.h, total 2520 md.ft Delta P Ratio (Total Skin) -0.762749 Fraction

k, average 74 md

Pi 3597.35 psia




1E-3 0.01 0.1 1 101

10

100

Log-Log plot: dp and dp' [psi] vs dt [hr]

SaphirRes_Log-Logplot Value Name Value

Gauge 1 build-up #1 Pi 3597.35 psia

Rate 0 STB/D k.h 2520 md.ft

Rate change 2300 STB/D k 74 md

P@dt=0 3086.62 psia L 287 ft

Pi 3597.35 psia Leakage 0.507397

Smoothing 0.1

Prod. Index 4.50336 [STB/D]/psiaDerived & Secondary Parameters







Semilog Line (Gauge 1 build-up #1)

Main Model Parameters From 26.1694 hr

C 0.00299 bbl/psi To 26.2194 hr

Total Skin -3.73 Slope 113.899 psi

k.h, total 2520 md.ft Intercept 3576.44 psia

k, average 74 md P@1hr 3425.66 psia

Pi 3597.35 psia k.h 2380 md.ft

k 70 md

Model Parameters p* 3576.44 psia

Well & Wellbore parameters (Moliere 1)

Skin -3.88

C 0.00299 bbl/psi Delta P Skin -384.326 psi

Skin -3.73





-4 -3.6 -3.2 -2.8 -2.4 -2 -1.6 -1.2 -0.8 -0.4

3200

3300

3400

3500

Semi-Log plot: p [psia] vs Superposition time

SaphirRes_Semi-Logplot Value Name Value

Gauge 1 build-up #1 Pi 3597.35 psia

Rate 0 STB/D k.h 2520 md.ft

Rate change 2300 STB/D k 74 md

P@dt=0 3086.62 psia L 287 ft

Pi 3597.35 psia Leakage 0.507397

Smoothing 0.1

Prod. Index 4.50336 [STB/D]/psiaDerived & Secondary Parameters







Semilog Line (Gauge 1 build-up #1)

Main Model Parameters From 26.1694 hr

C 0.00299 bbl/psi To 26.2194 hr

Total Skin -3.73 Slope 113.899 psi

k.h, total 2520 md.ft Intercept 3576.44 psia

k, average 74 md P@1hr 3425.66 psia

Pi 3597.35 psia k.h 2380 md.ft

k 70 md

Model Parameters p* 3576.44 psia

Well & Wellbore parameters (Moliere 1)

Skin -3.88

C 0.00299 bbl/psi Delta P Skin -384.326 psi

Skin -3.73


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