(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 1(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

Orientation

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 2(25 November 2003)

Orientation — This module focuses on familiari-zation with deliverability tests and the analysis and interpretation pressure transient test data. The following issues must be clear: test design, data acquisition/data quality control, and test execution are critical activities.Deliverability Testing:

"4-point" tests are appropriate (analyze as well tests).Isochronal/modified isochronal testing is difficult.

Pressure Transient Test Analysis/Interpretation:Conventional analysis — specialized plots.Model identification — type curves, simulation, etc.Test design — simplicity is the key.

Pressure Transient Testing

Pressure Transient Testing Slide — 3(25 November 2003)

Deliverability Testing — Basics

c. Modified "Isochronal" test sequence — note that each "buildup" is not required to achieve pi.

a. "Standard" 4-point test deliverability test — note that the rates increase (to protect the reservoir).

d. Governing equations for "deliverability" test analysis/interpretation.

b. "Isochronal" test sequence — note that each "buildup" is required to achieve pi.

Pressure Transient Testing Slide — 4(25 November 2003)

Well Test Analysis — Multirate Testing

a. Multirate (4-point) rate sequence (note pressure match (solid trend through the data).

b. Log-log "summary plot" — note good agreement in comparison of data and model.

c. Results summary — note that non-Darcy flow, changing wellbore storage, and an infinite-acting reservoir system were considered in this analysis.

Pressure Transient Testing Slide — 5(25 November 2003)

Well Test Analysis — "Well Interference"

a. "Well Interference" plot — note the linear trend through the data functions (confirms interference) .

b. Log-log "summary plot" — note the corrected and uncorrected data (well interference).

c. Horner semilog plot — note the two semilog trends confirm the radial composite model.

Discussion:"Well interference" is much more common than previously thought — and we must recognize the characteristic behavior on each plot: –Specialized plot (a).–Log-log plot (b).–Semilog plot (c).

Pressure Transient Testing Slide — 6(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

Basic Radial Flow Analysis

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 7(25 November 2003)

Well Test Analysis — Radial Flow Analysis (1/6)

a. Log-log "preliminary analysis" plot — wellbore storage and radial flow (Cs, k).

b. Cartesian "early-time" plot —used to analyze wellbore storage (p0, Cs).

c. Semilog "middle-time" plot —used to analyze radial flow behavior (k, s).

d. Horner "middle-time" plot —used to analyze radial flow behavior (k, s, p*).

f. Log-log "summary" plot —summary of all analysis (Cs, k, s, A, etc).

e. Cartesian "Arps" plot — used to estimate average reservoir pressure.

Pressure Transient Testing Slide — 8(25 November 2003)

Example: "Preliminary Analysis" (log-log).

Well Test Analysis — Radial Flow Analysis (2/6)

Pressure Transient Testing Slide — 9(25 November 2003)

Example: "Horner Semilog Analysis" (semilog).

Well Test Analysis — Radial Flow Analysis (3/6)

Pressure Transient Testing Slide — 10(25 November 2003)

Example: "Muskat-Arps Plot" (Cartesian).

Well Test Analysis — Radial Flow Analysis (4/6)

Pressure Transient Testing Slide — 11(25 November 2003)

Well Test Analysis — Radial Flow Analysis (5/6)

Example: "Analysis Summary Plot" (log-log).Pressure Transient Testing Slide — 12(25 November 2003)

Well Test Analysis — Radial Flow Analysis (6/6)

Given data — Lee text (1st edition), Example 2.2.

Working relations — Lee text (1st edition), Example 2.2).

Pressure Transient Testing Slide — 13(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

Type Curve Library:Radial Flow — Wellbore Storage and Skin Effects

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 14(25 November 2003)

Well Test Analysis — WBS Type Curves (1/4)

a. Type Curve: Radial flow with wellbore storage and skin effects (pD, pDd).

d. Type Curve: Radial flow with wellbore storage and skin effects (pDi, pDid).

b. Type Curve: Radial flow with wellbore storage and skin effects (pD, pDd, pDr1).

e. Type Curve: Radial flow with wellbore storage and skin effects (pDi, pDid, pDir1).

f. Type Curve: Radial flow with wellbore storage and skin effects (pDi, pDir2).

c. Type Curve: Radial flow with wellbore storage and skin effects (pD, pDdd).

Pressure Transient Testing Slide — 15(25 November 2003)

Well Test Analysis — WBS Type Curves (2/4)

Type Curve: "Gringarten-Bourdet" (pD, pDd).

Pressure Transient Testing Slide — 16(25 November 2003)

Well Test Analysis — WBS Type Curves (3/4)

Type Curve: "Second Derivative" (pD, pDdd).

Pressure Transient Testing Slide — 17(25 November 2003)

Type Curve: "Integral Functions" (pDi, pDid).

Well Test Analysis — WBS Type Curves (4/4)

Pressure Transient Testing Slide — 18(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

Type Curve Library:Radial Flow — Boundaries/Composite Reservoir

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 19(25 November 2003)

Well Test Analysis — Bounded Reservoir (1/3)

a. Type Curve for sealing faults (pDd). b. Type Curve for conductive (leaky) faults (pDd).

c. Type Curve for pressure buildup test in a closed rectangular reservoir (pDd).

d. Type Curve for pressure buildup test in a closed rectangular reservoir (pDid).

Pressure Transient Testing Slide — 20(25 November 2003)

Well Test Analysis — Bounded Reservoir (2/3)

Type Curve: "Sealing Faults" (pDd).

Pressure Transient Testing Slide — 21(25 November 2003)

Well Test Analysis — Bounded Reservoir (3/3)

Type Curve: "Closed Reservoir" (Buildup Only) (pDd).

Pressure Transient Testing Slide — 22(25 November 2003)

Well Test Analysis — Composite Systems (1/2)

a. Composite Reservoir (ηr=1x10-3). b. Composite Reservoir (ηr=1x10-2).

d. Composite Reservoir (ηr=1x100). e. Composite Reservoir (all ηr cases).

c. Composite Reservoir (ηr=1x10-1).

Pressure Transient Testing Slide — 23(25 November 2003)

Well Test Analysis — Composite Systems (2/2)

Type Curve: all ηr cases (Tang-Brigham).

Pressure Transient Testing Slide — 24(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

Type Curve Library:Vertically-Factured Wells

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 25(25 November 2003)

Well Test Analysis — Fractured Wells (1/5)

a. Type Curve: CfD= various, no CDf cases.

b. Type Curve: CfD=1, CDf = various. c. Type Curve: CfD=2, CDf = various.

d. Type Curve: CfD=5, CDf = various. f. Type Curve: CfD=1x103,CDf = various.

e. Type Curve: CfD=10, CDf = various.

Pressure Transient Testing Slide — 26(25 November 2003)

Well Test Analysis — Fractured Wells (2/5)

Type Curve: Various CfD (Cinco-Samaniego).

Pressure Transient Testing Slide — 27(25 November 2003)

Well Test Analysis — Fractured Wells (3/5)

"Pseudoradial flow" skin factor correlation for a fractured well (Cinco-Samaniego).

Pressure Transient Testing Slide — 28(25 November 2003)

Well Test Analysis — Fractured Wells (4/5)

Type Curve: CfD=2, various CDf cases.

Pressure Transient Testing Slide — 29(25 November 2003)

Type Curve: CfD=1x103, various CDf cases.

Well Test Analysis — Fractured Wells (5/5)

Pressure Transient Testing Slide — 30(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

Type Curve Library:Dual Porosity (Naturally Fractured) Reservoirs

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 31(25 November 2003)

Well Test Analysis — Dual Porosity Reservoirs (1/5)

b. Type Curve: λCD= 1x10-1, pssinterporosity flow.

a. Type Curve: ω,λ= various, pss interporosity flow.

c. Type Curve: λCD= 1x10-4, pssinterporosity flow.

d. Type Curve: ω,λ= various, tran-sient interporosity flow.

f. Type Curve: λCD= 1x10-4, transient interporosity flow.

e. Type Curve: λCD= 1x10-1, transient interporosity flow.

Pressure Transient Testing Slide — 32(25 November 2003)

Well Test Analysis — Dual Porosity Reservoirs (2/5)

Type Curve: Pseudosteady-State Interporosity Flow (Onur, et al format).

Pressure Transient Testing Slide — 33(25 November 2003)

Well Test Analysis — Dual Porosity Reservoirs (3/5)

Type Curve: Transient Interporosity Flow (Onur, et al format).

Pressure Transient Testing Slide — 34(25 November 2003)

Well Test Analysis — Dual Porosity Reservoirs (4/5)

Type Curve: λCD= 1x10-4, pss interporosity flow.

Pressure Transient Testing Slide — 35(25 November 2003)

Well Test Analysis — Dual Porosity Reservoirs (5/5)

Type Curve: λCD= 1x10-4, transient interporosity flow.

Pressure Transient Testing Slide — 36(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

Example Case: Pre- and Post-Fracture Buildup Tests

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 37(25 November 2003)

Example — Pre-Fracture Buildup Analysis (1/4)

b. Cartesian "early-time" plot —used to analyze wellbore storage (p0, Cs).

c. Semilog "middle-time" plot —used to analyze radial flow behavior (k, s).

a. Log-log "pre-analysis" plot (∆tae format) — orientation and identification of flow regimes.

d. Horner "middle-time" plot —used to analyze radial flow behavior (k, s, etc.).

e. Log-log "summary" plot (∆taformat) — summary of all analysis (Cs, k, s, etc).

f. Log-log "summary" plot (∆taeformat) — summary of all analysis (Cs, k, s, etc).

Pressure Transient Testing Slide — 38(25 November 2003)

Example — Pre-Fracture Buildup Analysis (2/4)

Example: "Preliminary Analysis" (log-log).

Pressure Transient Testing Slide — 39(25 November 2003)

Example — Pre-Fracture Buildup Analysis (3/4)

Example: "Horner Semilog Analysis" (semilog).

Pressure Transient Testing Slide — 40(25 November 2003)

Example — Pre-Fracture Buildup Analysis (4/4)

Example: "Analysis Summary Plot" (log-log).Pressure Transient Testing Slide — 41(25 November 2003)

Example — Post-Fracture Buildup Analysis (1/5)

b. Cartesian "early-time" plot —used to analyze wellbore storage (p0, Cs).

c. Semilog "middle-time" plot —used to analyze radial flow behavior (k, s).

a. Log-log "pre-analysis" plot (∆tae format) — orientation and identification of flow regimes.

d. Horner "middle-time" plot —used to analyze radial flow behavior (k, s, etc.).

e. "Type curve" plot (∆tae format) — summary of all analysis (CDf, k, xf, CfD).

f. Log-log "summary" plot (∆taeformat) — summary of all analysis (CDf, k, xf, CfD).

Pressure Transient Testing Slide — 42(25 November 2003)

Example — Post-Fracture Buildup Analysis (2/5)

Example: "Preliminary Analysis" (log-log).

Pressure Transient Testing Slide — 43(25 November 2003)

Example — Post-Fracture Buildup Analysis (3/5)

Example: "Horner Semilog Analysis" (semilog).

Pressure Transient Testing Slide — 44(25 November 2003)

Example: "Type Curve Plot" (log-log).

Example — Post-Fracture Buildup Analysis (4/5)

Pressure Transient Testing Slide — 45(25 November 2003)

Example — Post-Fracture Buildup Analysis (5/5)

Example: "Analysis Summary Plot" (log-log).Pressure Transient Testing Slide — 46(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

Comment

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 47(25 November 2003)

Well Test Analysis — Scaling

Pressure transient analysis "sees" the reservoir as a volume-averaged set of properties.New solutions/models will also have this view of the reservoir —but, quantifying heterogeneity may (or may not) be possible by the analysis of pressure transient test data.Scaling will remain a major issue — regardless of the mechanism used to analyze reservoir performance.

From: Simulator Parameter Assignment and the Problem of Scaling in Reservoir Engineering — Halderson (1986).

Pressure Transient Testing Slide — 48(25 November 2003)

(Formation Evaluation and the Analysis of Reservoir Performance)

Module for:Analysis of Reservoir PerformancePressure Transient Testing

End of Presentation

T.A. Blasingame, Texas A&M U.Department of Petroleum Engineering

Texas A&M UniversityCollege Station, TX 77843-3116 (USA)

(+1) 979.845.2292 — t-blasingame@tamu.eduPressure Transient Testing Slide — 49(25 November 2003)

References: Pressure Transient TestingText/References:

1. Lee, W.J.: Well Testing, (1st edition) SPE (1982).2. Lee, W.J. and Wattenbarger, R.A.: Gas Reservoir Engineering, SPE (1996).3. Dake, L. P.: Fundamentals of Reservoir Engineering, Elsevier (1978).4. ERCB Gas Well Testing Manual (1975 version), Alberta Energy Resources Conservation Board (Calgary, Canada).

General:1. Course Motes for PETE 324, Well Performance Analysis, Texas A&M U., College Station, TX (http://pumpjack.tamu.edu/~t-

blasingame/P324_reference/).2. Blasingame, T.A., Johnston, J.L., and Lee, W.J.: "Type Curve Analysis Using the Pressure Integral Method," paper SPE 18799

presented at the 1989 SPE California Regional Meeting, Bakersfield, CA, 05-07 April 1989.3. Banthai, B.S., Meyer, B.M., and Blasingame, T.A.: "Use of Surface Derived Pressure Measurements for the Cost-Effective Reservoir

Surveillance of Waterflood Operations in the Permian Basin," SPE paper 27685 presented at the SPE Permian Basin Oil and Gas Recovery Conference, Midland, TX, 16-18 March 1994.

4. Ansah, J., Likitsupin, P., and Blasingame, T.A.: "Determination of Reservoir Pore Volume From Pressure Buildup Tests Using Type Curves," paper SPE 29584 presented at the 1995 Joint Rocky Mountain Regional/Low Permeability Reservoirs Symposium, Denver, CO, 20-22 March, 1995.

5. Stewart, G., Gupta, A., and Westaway, P.: "The Interpretation of Interference Tests in a Reservoir With Sealing and Partially Communicating Faults," paper SPE 12967 presented at the 1984 European Petroleum Conference held in London, England 25-28 Oct. 1984.

6. Abbaszadeh, M. and Cinco-Ley, H.: Pressure-Transient Behavior in a Reservoir with a Finite-Conductivity Fault," SPEFE (March 1995), 26-32.

7. Raghavan, R.: Well Test Analysis, Prentice-Hall, 1993, 154-158.8. Tang, R.W. and Brigham, W.E.: "Transient Pressure Analysis in Composite Reservoirs," Topical Report SUPRI TR-31 (1982).9. Cinco-Ley, H., Samaniego-V., F.: "Effect of Wellbore Storage and Damage on the Transient Pressure Behavior of Vertically Fractured

Wells," paper SPE 6752 presented at the 1977 SPE Annual Technical Conference and Exhibition, Denver, CO, 9-12 Oct.10. Wong, D.W., Harrington, A.G., and Cinco-Ley, H.: "Application to the Pressure Derivative Function in the Pressure Transient Testing

of Fractured Wells," SPEFE (October 1986) 470-480.11. Stewart, G. and Ascharsobbi, F.: "Well Test Interpretation for Naturally Fractured Reservoirs," paper SPE 18173 presented at the SPE

Annual Technical Conference and Exhibition, Houston, TX, 2-5 Oct., 1988.12. Onur, M., Satman, A., and Reynolds, A.C.: "New Type Curves for Analyzing the Transition Time Data From Naturally Fractured

Reservoirs," paper SPE 25873 presented at the SPE Rocky Mountain Regional/Low Permeability Reservoirs Symposium, Denver, CO, 12-14 April, 1993.

Pressure Transient Testing Slide — 50(25 November 2003)