Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases 07 April 2003 — Due: Monday 14 April 2003 Field Case : Mid-Continent Gas Well These gas well test data were obtained from an operator in the Mid-Continent region of the U.S. The appropriate pseudopressure and pseudotime transforms are applied — you can simply analyze these well test data in the same manner as you would for data from an oil well test. Note that you are given 2 (two) separate tests — a pre-fracture buildup test that has some apparent wellbore storage anomalies, and a post-fracture pressure buildup test that exhibits fractured well behavior. Reservoir properties: f = 0.095 r w = 0.33 ft h = 96 ft Gas properties: (at the initial reservoir pressure (p i ) of 5700 psia) γ g = 0.718 (air = 1.0) T = 190 deg F B gi = 0.6052 RB/MSCF m gi = 0.0345 cp c t = c gi = 9.55x10 -5 psia -1 Production parameters: Pre-Fracture Buildup: p pwf (∆t=0) = 626.02 psia q g = 1,900 MSCF/D t p = 64 hr Post-Fracture Buildup: p pwf (∆t=0) = 2535.20 psia q g = 10,500 MSCF/D t p = 2130 hr Required : For this problem, you are to perform the following analyses: l "Preliminary" log-log analysis. l Cartesian analysis of "early" time (wellbore storage distorted) data. l Semilog analysis of "middle" time (radial flow) data. l Log-log type curve analysis. You are to complete the tables on the attached pages which are provided for you to tabulate your results. Hint : Focus on the analysis of the post-fracture data first, the pre-fracture data are severely distorted — apparently by anomalous wellbore storage conditions, but also (possibly) by near-well fluid (condensate) banking.
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003
Field Case: Mid-Continent Gas Well
These gas well test data were obtained from an operator in the Mid-Continent region of the U.S. The appropriate pseudopressure and pseudotime transforms are applied — you can simply analyze these well test data in the same manner as you would for data from an oil well test.
Note that you are given 2 (two) separate tests — a pre-fracture buildup test that has some apparent wellbore storage anomalies, and a post-fracture pressure buildup test that exhibits fractured well behavior.
Reservoir properties: φ = 0.095 rw = 0.33 ft h = 96 ft
Gas properties: (at the initial reservoir pressure (pi) of 5700 psia) γg = 0.718 (air = 1.0) T = 190 deg F Bgi = 0.6052 RB/MSCF µgi = 0.0345 cp ct = cgi = 9.55x10-5 psia-1
For this problem, you are to perform the following analyses:
l "Preliminary" log-log analysis. l Cartesian analysis of "early" time (wellbore storage distorted) data. l Semilog analysis of "middle" time (radial flow) data. l Log-log type curve analysis.
You are to complete the tables on the attached pages which are provided for you to tabulate your results.
Hint:
Focus on the analysis of the post-fracture data first, the pre-fracture data are severely distorted — apparently by anomalous wellbore storage conditions, but also (possibly) by near-well fluid (condensate) banking.
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Governing Equations
where the formation permeability, k, and the skin factor, s, are given by:
hm
Bqk
sl
gigig µ6.162= and
+
−
=∆−=∆= 2275.3
2log
0))(hr) 1((1513.1
wrticgi
k
slmatpwfpatpwsp
sφµ
Type Curve Analysis Relations: (pseudopressure-pseudotime form)
"Bourdet -Gringarten" Type Curves: "Economides" Type Curves: (Unfractured Vertical Well with (Fractured Vertical Well with Wellbore Storage and Skin Effects) Wellbore Storage Effects)
Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Required Results — Pre-Fracture Pressure Buildup Test Data (Mid-continent gas well)
Required: Pre-Fracture Pressure Buildup Test Data (Mid-continent gas well)
You are to estimate the following:
l "Preliminary" log-log analysis: a. The wellbore storage coefficient, Cs. b. The dimensionless wellbore storage coefficient, CD. c. The formation permeability, k.
l Cartesian analysis of "early" time (wellbore storage distorted) data: a. The pseudopressure at the start of the test, ppws(∆t=0). b. The wellbore storage coefficient, Cs. c. The dimensionless wellbore storage coefficient, CD.
l Semilog analysis of "middle" time (radial flow) data: (use both Horner and MDH methods) a. The formation permeability, k. b. The near well skin factor, s. c. The radius of investigation, rinv, at the end of radial flow or the end of the test data.
l Log-log type curve analysis: (use ∆tae methods) a. The formation permeability, k. b. The near well skin factor, s. c. The wellbore storage coefficient, Cs. d. The dimensionless wellbore storage coefficient, CD.
Results: Pre-Fracture Pressure Buildup Test Data (Mid-continent gas well)
Log-log Analysis:
Wellbore storage coefficient, Cs = RB/psi
Dimensionless wellbore storage coefficient, CD =
Formation permeability, k = md
Cartesian Analysis: Early Time Data
Pressure drop at the start of the test, ppws(∆t=0) = psi
Wellbore storage coefficient, Cs = RB/psi
Dimensionless wellbore storage coefficient, CD =
Semilog Analysis: Horner ∆ta (MDH)
Formation permeability, k = md = md
Near well skin factor, s = =
Radius of investigation, rinv (end of radial flow or end of test) = ft = ft
Dimensionless wellbore storage coefficient, CD = =
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Required Results — Post-Fracture Pressure Buildup Test Data (Mid-continent gas well)
Required: Post-Fracture Pressure Buildup Test Data (Mid-continent gas well)
You are to estimate the following:
l "Preliminary" log-log analysis: a. The wellbore storage coefficient, Cs. b. The dimensionless wellbore storage coefficient, CDf (based on xf). c. The formation permeability, k.
l Cartesian analysis of "early" time (wellbore storage distorted) data: a. The pseudopressure at the start of the test, ppws(∆t=0). b. The wellbore storage coefficient, Cs. c. The dimensionless wellbore storage coefficient, CDf (based on xf).
l Semilog analysis of "middle" time (radial flow) data: (use both Horner and MDH methods) a. The formation permeability, k. b. The near well skin factor, s. c. The radius of investigation, rinv, at the end of radial flow or the end of the test data.
l Log-log type curve analysis: (use ∆tae methods) a. The dimensionless fracture conductivity, CfD. b. The formation permeability, k. c. The fracture half-length, xf. d. The wellbore storage coefficient, Cs. e. The dimensionless wellbore storage coefficient, CD. f. The pseudoradial flow skin factor, spr.
Results: Post-Fracture Pressure Buildup Test Data (Mid-continent gas well)
Log-log Analysis:
Wellbore storage coefficient, Cs = RB/psi
Dimensionless wellbore storage coefficient, CDf (based on xf) =
Formation permeability, k = md
Cartesian Analysis: Early Time Data
Pressure drop at the start of the test, ppws(∆t=0) = psi
Wellbore storage coefficient, Cs = RB/psi
Dimensionless wellbore storage coefficient, CDf (based on xf) =
Semilog Analysis: Horner ∆ta (MDH)
Formation permeability, k = md = md
Near well skin factor, s = =
Radius of investigation, rinv (end of radial flow or end of test) = ft = ft
Log-Log Type Curve Analysis: ∆tae (∆ta=∆tae, tp=2130 hr)
Dimensionless fracture conductivity, CfD =
Formation permeability, k = md
Fracture half-length, xf = ft
Wellbore storage coefficient, Cs = RB/psi
Dimensionless wellbore storage coefficient, CDf (based on xf) =
Pseudoradial flow skin factor, spr =
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Pre-Fracture Pressure Buildup Test Data
Field Case: Mid-Continent Gas Well
Well Test Data Functions: Pre-Fracture Pressure Buildup Test Data
Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 "Cinco-Samaniego" Type Curve
"Cinco-Samaniego" Type Curve: pwD and pwD' vs. tDxf — Various CfD Values (NO WELLBORE STORAGE EFFECTS) (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 "Cinco-Samaniego" Skin Factor Correlation
"Cinco-Samaniego" Skin Factor Correlation: (used to relate the fractured well case to the Pseudoradial flow skin factor)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Bourdet-Gringarten Type Curve (Unfractured Well)
Bourdet-Gringarten Type Curve: pwD and pwD' vs. tD/CD — Various CD Values (Radial Flow Case — Includes Wellbore Storage and Skin Effects) (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 "Economides" Type Curve (CfD =1, CDf =various)
"Economides" Type Curve: pwD and pwD' vs. tDxf/CDf — CfD =1 (Fractured Well Case — Includes Wellbore Storage Effects) (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 "Economides" Type Curve (CfD =2, CDf =various)
"Economides" Type Curve: pwD and pwD' vs. tDxf/CDf — CfD =2 (Fractured Well Case — Includes Wellbore Storage Effects) (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 "Economides" Type Curve (CfD =2, CDf =various)
"Economides" Type Curve: pwD and pwD' vs. tDxf/CDf — CfD =5 (Fractured Well Case — Includes Wellbore Storage Effects) (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 "Economides" Type Curve (CfD =10, CDf =various)
"Economides" Type Curve: pwD and pwD' vs. tDxf/CDf — CfD =10 (Fractured Well Case — Includes Wellbore Storage Effects) (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 "Economides" Type Curve (CfD =1x10-3, CDf =various)
"Economides" Type Curve: pwD and pwD' vs. tDxf/CDf — CfD =1x103 (Fractured Well Case — Includes Wellbore Storage Effects) (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Ansah Type Curve — Pressure Buildup in a Bounded (Closed) Reservoir System
Ansah Type Curve: Pressure Buildup in a Bounded (Closed) Reservoir System (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Stewart Type Curve — Well in an Infinite-Acting Reservoir System with a Single or Multiple Sealing Faults
Stewart Type Curve: Well in an Infinite-Acting Reservoir System with a Single or Multiple Sealing Faults. (1"x1" format)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Early-Time Cartesian Plot — Pre-Fracture Gas Well Pressure Buildup Case
Early-Time Cartesian Plot: Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Wellbore Storage Distorted Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Semilog Plot — Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
Semilog Plot: Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Horner Semilog Plot — Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
Horner Semilog Plot: Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Log-Log Plot — Pre-Fracture Gas Well Pressure Buildup Case — (No Rate History Included — Using Shut-In Pseudotime)
Log-Log Plot: Pre-Fracture Gas Well Pressure Buildup Case — (No Rate History Included — Using Shut-In Pseudotime)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Log-Log Plot — Pre-Fracture Gas Well Pressure Buildup Case — (Rate History Included — Using Effective Pseudotime)
Log-Log Plot: Pre-Fracture Gas Well Pressure Buildup Case — (Rate History Included — Using Effective Pseudotime)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Semilog Plot (Results) — Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
Semilog Plot (Results): Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Horner Semilog Plot (Results) — Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
Horner Semilog Plot (Results): Pre-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Log-Log Plot (Results) — Pre-Fracture Gas Well Pressure Buildup Case — (No Rate History Included — Using Shut-In Pseudotime)
Log-Log Plot (Results): Pre-Fracture Gas Well Pressure Buildup Case — (No Rate History Included — Using Shut-In Pseudotime)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Log-Log Plot (Results) — Fracture Gas Well Pressure Buildup Case — (Rate History Included — Using Effective Pseudotime)
Log-Log Plot (Results): Pre-Fracture Gas Well Pressure Buildup Case — (Rate History Included — Using Effective Pseudotime)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Early-Time Cartesian Plot — Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Wellbore Storage Distorted Data)
Early-Time Cartesian Plot: Post-Fracture Gas Well Pressure Buildup Case—Pseudopressure Data (Wellbore Storage Distorted Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Semilog Plot Post — Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
Semilog Plot: Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
30
Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Horner Semilog Plot — Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
Horner Semilog Plot: Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Log-Log Plot — Post-Fracture Gas Well Pressure Buildup Case — (Rate History Included — Using Effective Pseudotime)
Log-Log Plot: Post-Fracture Gas Well Pressure Buildup Case — (Rate History Included — Using Effective Pseudotime)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Early-Time Cartesian Plot (Results) — Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Wellbore Storage Distorted Data)
Early-Time Cartesian Plot (Results): Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Wellbore Storage Distorted Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Semilog Plot (Results) — Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
Semilog Plot (Results): Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Horner Semilog Plot (Results) — Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
Horner Semilog Plot (Results): Post-Fracture Gas Well Pressure Buildup Case — Pseudopressure Data (Undistorted Radial Flow Data)
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Petroleum Engineering 324 — Well Performance Homework No. 8 — Pre- and Post-Fracture Gas Well Pressure Buildup Cases
07 April 2003 — Due: Monday 14 April 2003 Log-Log Plot (Results) — Post-Fracture Gas Well Pressure Buildup Case — (Rate History Included — Using Effective Pseudotime)
Log-Log Plot (Results): Post-Fracture Gas Well Pressure Buildup Case — (Rate History Included — Using Effective Pseudotime)