Analysis of Water Well Test Data (2003) (Texas A&M University)

Introduction: READ THIS FIRST!

This problem consists of a pressure drawdown/buildup test sequence performed on a pumping WATER well (our campus water well). There are no "tricks" involved — this should be a straightforward analysis/interpretation se-quence. Be sure to perform all analyses — and cross-check/double-check your work whenever possible.

Given:

These attached data were taken from a pressure drawdown/buildup test sequence performed on our campus water well. The reservoir interval is a water sand at about 450 ft — the well is not stimulated and should not be damaged — however, the well is completed "open hole," so some evidence of stimulation is possible. The reservoir should be assumed to be homogeneous and infinite-acting.

Reservoir properties:

φ=0.25 rw=0.36 ft ct=6.5x10-6 psia-1 h=23 ft

Water properties:

Bw=1.0 RB/STB μw=1.0 cp

Production parameters:

Event

Duration of Event

(hr)

Pressure at start of Event

(psia)

Water Flowrate (STB/D)

1. Drawdown Test ≈ 2.054 pi=147.29 60 2. Buildup Test ≈ 2.25 pwf(Δt=0)=139.3 0

Summary Plots: (Drawdown/Buildup Test Sequences)

Required: (general)

Provide a comprehensive HAND ANALYSIS of these test data — type curves ("Bourdet-Gringarten" and "Ansah") are provided for hand analysis. You are also permitted to perform SUPPLEMENTARY analyses of these data using software (e.g., your own software, Saphir, FAST, etc.) — HOWEVER, YOU ARE REQUIRED TO SUBMIT HAND ANALYSES OF THESE DATA.

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Analysis of Water Well Test Data (2003) (Texas A&M University) Results (Drawdown Case)

Required: Pressure Drawdown Analysis of Water Well Test Data (Texas A&M University — 2003)

You are to estimate the following:

Preliminary log-log analysis: a. The wellbore storage coefficient, Cs. b. The formation permeability, k.

Cartesian analysis of "early" time (wellbore storage distorted) data: a. The pressure at the start of the test, pi. b. The wellbore storage coefficient, Cs.

Semilog analysis of "middle" time (radial flow) data: a. The formation permeability, k. b. The near well skin factor, s. Results: Pressure Drawdown Analysis of Water Well Test Data (Texas A&M University — 2003)

Preliminary Log-Log Analysis:

Wellbore storage coefficient, Cs = RB/psi

Formation permeability, k = md

Cartesian Analysis: Early Time Data

Pressure at start of test, pi = psia

Wellbore storage coefficient, Cs = RB/psi

Semilog Analysis:

Formation permeability, k = md

Near well skin factor, s =

3

Analysis of Water Well Test Data (2003) (Texas A&M University) Results (Buildup Case)

Required: Pressure Buildup Analysis of Water Well Test Data (Texas A&M University — 2003)

You are to estimate the following:

Preliminary log-log analysis: a. The wellbore storage coefficient, Cs. b. The formation permeability, k.

Cartesian analysis of "early" time (wellbore storage distorted) data: a. The pressure at the start of the test, pwf(Δt=0). b. The wellbore storage coefficient, Cs.

Semilog analysis of "middle" time (radial flow) data: a. The formation permeability, k. b. The near well skin factor, s.

Cartesian analysis of "late" time (boundary-dominated) data: "Muskat Plot" a. Average pressure, p . Results: Pressure Buildup Analysis of Water Well Test Data (Texas A&M University — 2003)

Preliminary Log-Log Analysis: (Δte and Δt (MDH) analysis) Δte Δt (MDH)

Wellbore storage coefficient, Cs = RB/psi = RB/psi

Formation permeability, k = md = md

Cartesian Analysis: Early Time Data

Pressure at start of test, pwf(Δt=0) = psia

Wellbore storage coefficient, Cs = RB/psi

Semilog Analysis: (Horner and MDH analysis) Horner Δte Δt (MDH)

Formation permeability, k = md = md = md

Near well skin factor, s = = =

Cartesian Analysis: Late Time Data ("Muskat Plot")

Average pressure, p (if applicable) = psia

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Analysis of Water Well Test Data (2003) (Texas A&M University) Drawdown Test Data

Data Functions: Pressure Drawdown Case

Point

t (hr)

pwf (psia)

Δp (psi)

Δp' (psi)

1 0.0042 146.98 0.307 0.3117 2 0.0083 146.68 0.613 0.4685 3 0.0125 146.50 0.794 0.7677 4 0.0167 146.24 1.046 0.8560 5 0.0208 145.92 1.371 0.8609 6 0.0250 145.74 1.552 1.2644 7 0.0292 145.63 1.660 1.3669 8 0.0333 145.45 1.840 1.4444 9 0.0375 145.31 1.985 1.3695

10 0.0417 145.16 2.129 1.4228 11 0.0458 144.95 2.345 1.4908 12 0.0542 144.58 2.706 1.7374 13 0.0625 144.33 2.959 1.8189 14 0.0708 144.08 3.211 1.8992 15 0.0792 143.95 3.338 1.8622 16 0.0875 143.86 3.428 1.7132 17 0.0958 143.77 3.518 1.6968 18 0.1042 143.57 3.717 1.5785 19 0.1125 143.36 3.933 1.5360 20 0.1208 143.16 4.132 1.5626 21 0.1375 143.05 4.240 1.4033 22 0.1542 142.91 4.384 1.3954 23 0.1708 142.78 4.510 1.4944 24 0.1875 142.67 4.619 1.3573 25 0.2042 142.60 4.691 1.2162 26 0.2208 142.46 4.835 1.1080 27 0.2375 142.40 4.889 1.1431 28 0.2542 142.35 4.943 1.1826 29 0.2708 142.26 5.034 1.2060 30 0.2875 142.22 5.070 1.1989 31 0.3042 142.13 5.160 1.2172 32 0.3208 142.09 5.196 1.2415 33 0.3375 142.04 5.250 1.2473 34 0.3542 142.00 5.286 1.2884 35 0.3708 141.93 5.358 1.2225 36 0.3875 141.90 5.394 1.2358 37 0.4042 141.84 5.449 1.1947 38 0.4208 141.81 5.485 1.1808 39 0.4375 141.70 5.593 1.2256 40 0.4542 141.64 5.647 1.2847 41 0.4708 141.61 5.683 1.2911 42 0.4875 141.54 5.755 1.2893 43 0.5042 141.50 5.791 1.3508 44 0.5208 141.45 5.845 1.3988 45 0.5375 141.39 5.900 1.4110 46 0.5542 141.34 5.954 1.3888 47 0.5708 141.28 6.008 1.4318 48 0.5875 141.25 6.044 1.4324 49 0.6042 141.19 6.098 1.4537 50 0.6208 141.16 6.134 1.4516

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Analysis of Water Well Test Data (2003) (Texas A&M University) Drawdown Test Data (Continued)

Data Functions: Pressure Drawdown Case (Continued)

Point

t (hr)

pwf (psia)

Δp (psi)

Δp' (psi)

51 0.6375 141.08 6.206 1.4909 52 0.7208 141.03 6.260 1.5017 53 0.8042 140.90 6.387 1.4604 54 0.8875 140.72 6.567 1.4392 55 0.9708 140.51 6.784 1.4745 56 1.0542 140.40 6.892 1.4602 57 1.1375 140.29 7.000 1.4555 58 1.2208 140.15 7.144 1.5477 59 1.3042 140.07 7.217 1.7314 60 1.3875 139.98 7.307 1.7255 61 1.4708 139.91 7.379 1.7646 62 1.5542 139.86 7.433 1.7110 63 1.6375 139.79 7.505 1.6359 64 1.7208 139.71 7.577 1.6371 65 1.8042 139.62 7.668 1.5155 66 1.8875 139.55 7.740 1.5420 67 1.9708 139.51 7.776 1.4999 68 2.0542 139.46 7.830 1.4844

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Analysis of Water Well Test Data (2003) (Texas A&M University) Pressure Buildup Test Data

Data Functions: Pressure Buildup Case (Continued)

Point

Δt (hr)

Δte (hr)

Horner Time

pws (psia)

Δp (psi)

Δp'(Δt) (psi)

Δp'(Δte) (psi)

1 0.00417 0.00416 494.00 139.55 0.2500 0.4465 0.4482 2 0.00833 0.00830 247.50 139.78 0.4847 0.4761 0.5863 3 0.01250 0.01242 165.33 140.04 0.7372 0.6496 0.7524 4 0.01667 0.01653 124.25 140.25 0.9537 0.8573 0.9280 5 0.02083 0.02062 99.60 140.47 1.1702 1.0077 1.1101 6 0.02500 0.02470 83.17 140.65 1.3507 1.1831 1.2773 7 0.02917 0.02876 71.43 140.87 1.5672 1.3363 1.3882 8 0.03333 0.03280 62.63 141.07 1.7656 1.4840 1.4466 9 0.03750 0.03683 55.78 141.23 1.9280 1.5453 1.5409

10 0.04167 0.04084 50.30 141.34 2.0363 1.5922 1.6488 11 0.04583 0.04483 45.82 141.57 2.2708 1.7493 1.6789 12 0.05000 0.04881 42.08 141.68 2.3790 1.8102 1.7006 13 0.05417 0.05278 38.92 141.88 2.5775 1.8593 1.8375 14 0.05833 0.05672 36.21 142.00 2.7038 1.8630 1.8636 15 0.06250 0.06065 33.87 142.17 2.8662 1.9784 1.8951 16 0.06667 0.06457 31.81 142.26 2.9564 1.9843 1.9121 17 0.07083 0.06847 30.00 142.35 3.0466 2.0171 1.9460 18 0.07500 0.07236 28.39 142.45 3.1548 2.0352 1.9832 19 0.07917 0.07623 26.95 142.56 3.2631 2.1403 2.0224 20 0.08333 0.08008 25.65 142.65 3.3533 2.0667 2.0220 21 0.09167 0.08775 23.41 142.89 3.5878 2.1739 2.0777 22 0.10000 0.09536 21.54 143.03 3.7322 2.1005 2.0849 23 0.10833 0.10291 19.96 143.14 3.8404 2.1185 2.0994 24 0.11667 0.11040 18.61 143.39 4.0930 2.1298 2.0805 25 0.12500 0.11783 17.43 143.52 4.2193 2.1778 2.0746 26 0.13333 0.12521 16.41 143.65 4.3456 2.2077 2.0360 27 0.14167 0.13253 15.50 143.75 4.4538 2.1873 2.0586 28 0.15000 0.13979 14.69 143.88 4.5801 2.2009 2.0776 29 0.15833 0.14700 13.97 144.01 4.7064 2.1845 2.0554 30 0.16667 0.15416 13.33 144.11 4.8147 2.1729 2.0496 31 0.17500 0.16126 12.74 144.19 4.8868 2.1184 2.0454 32 0.18333 0.16831 12.20 144.31 5.0131 2.1219 2.0263 33 0.20000 0.18226 11.27 144.44 5.1394 2.1012 1.9580 34 0.21667 0.19599 10.48 144.64 5.3379 2.1551 1.9553 35 0.23333 0.20953 9.80 144.73 5.4281 1.9794 1.9450 36 0.25000 0.22288 9.22 144.87 5.5724 1.9673 1.8406 37 0.26667 0.23603 8.70 144.96 5.6626 1.9282 1.8017 38 0.28333 0.24899 8.25 145.09 5.7889 1.8812 1.7567 39 0.30000 0.26177 7.85 145.14 5.8430 1.7986 1.7336 40 0.31667 0.27437 7.49 145.23 5.9332 1.7516 1.7112 41 0.33333 0.28679 7.16 145.32 6.0235 1.7562 1.6772 42 0.41667 0.34640 5.93 145.63 6.3302 1.5923 1.4899 43 0.50000 0.40212 5.11 145.85 6.5467 1.4051 1.3659 44 0.58333 0.45432 4.52 145.99 6.6910 1.2938 1.2703 45 0.66667 0.50332 4.08 146.10 6.7992 1.2218 1.1940 46 0.75000 0.54941 3.74 146.21 6.9075 1.1551 1.1885 47 0.83333 0.59283 3.47 146.30 6.9977 1.1114 1.1519 48 0.91667 0.63382 3.24 146.37 7.0699 1.2932 1.1323 49 1.00000 0.67258 3.05 146.39 7.0879 1.2078 1.0924 50 1.08333 0.70927 2.90 146.46 7.1601 1.2309 1.0585

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Analysis of Water Well Test Data (2003) (Texas A&M University) Pressure Buildup Test Data (Continued)

Data Functions: Pressure Buildup Case (Continued)

Point

Δt (hr)

Δte (hr)

Horner Time

pws (psia)

Δp (psi)

Δp'(Δt) (psi)

Δp'(Δte) (psi)

51 1.16667 0.74407 2.76 146.50 7.1962 1.1061 1.0424 52 1.25000 0.77711 2.64 146.53 7.2322 1.0933 1.0320 53 1.33333 0.80853 2.54 146.59 7.2864 1.0775 1.0076 54 1.41667 0.83844 2.45 146.60 7.3044 1.0457 0.9921 55 1.50000 0.86694 2.37 146.62 7.3225 1.0220 0.9807 56 1.58333 0.89414 2.30 146.66 7.3585 1.0336 0.9837 57 1.66667 0.92012 2.23 146.68 7.3766 0.9965 0.9628 58 1.75000 0.94496 2.17 146.69 7.3946 0.9854 0.9571 59 1.83333 0.96874 2.12 146.73 7.4307 1.0079 0.9651 60 1.91667 0.99152 2.07 146.75 7.4487 0.9518 0.9619 61 2.00000 1.01336 2.03 146.77 7.4668 0.9496 0.9538 62 2.08333 1.03432 1.99 146.78 7.4848 0.9497 0.9527 63 2.16667 1.05446 1.95 146.80 7.5029 0.9082 0.9524 64 2.25000 1.07381 1.91 146.82 7.5209 0.9129 0.9529

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Analysis of Water Well Test Data (2003) (Texas A&M University) Bourdet-Gringarten Type Curve — Wellbore Storage and Skin Effects

Bourdet-Gringarten Type Curve: Dimensionless Pressure and Pressure Derivative Functions

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Analysis of Water Well Test Data (2003) (Texas A&M University) 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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Analysis of Water Well Test Data (2003) (Texas A&M University) Log-Log Plot (Pressure Drawdown Case)

Log-Log Plot: Pressure Drawdown Case — Pressure Drop and Pressure Drop Derivative Data

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Analysis of Water Well Test Data (2003) (Texas A&M University) Early-Time Cartesian Plot (Pressure Drawdown Case)

Early-Time Cartesian Plot: Pressure Drawdown Case

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Analysis of Water Well Test Data (2003) (Texas A&M University) Semilog Plot (Pressure Drawdown Case)

Semilog Plot: Pressure Drawdown Case

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Analysis of Water Well Test Data (2003) (Texas A&M University) Log-Log Plot (Pressure Buildup Case — Shut-In Time Format)

Log-Log Plot: Pressure Buildup Case — Pressure Drop and Pressure Drop Derivative Data

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Analysis of Water Well Test Data (2003) (Texas A&M University) Log-Log Plot (Pressure Buildup Case — Effective Time Format)

Log-Log Plot: Pressure Buildup Case — Pressure Drop and Pressure Drop Derivative Data — Effective Time Format

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Analysis of Water Well Test Data (2003) (Texas A&M University) Early-Time Cartesian Plot (Pressure Buildup Case)

Early-Time Cartesian Plot: Pressure Buildup Case

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Analysis of Water Well Test Data (2003) (Texas A&M University) Semilog Plot (Pressure Buildup Case

Semilog Plot: Pressure Buildup Case

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Analysis of Water Well Test Data (2003) (Texas A&M University) Horner Semilog Plot (Pressure Buildup Case)

Horner Semilog Plot: Pressure Buildup Case

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Petroleum Engineering 648 — Pressure Transient Testing Homework 12 — Analysis of Water Well Test Data (2003) (Texas A&M University)

26 July 2004 — Due: Monday 02 August 2004 Semilog Plot (Pressure Buildup Case — Effective Time Format)

Semilog Plot: Pressure Buildup Case — Effective Time Format

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Analysis of Water Well Test Data (2003) (Texas A&M University) Late-Time Cartesian Plot ("Muskat Plot") (Pressure Buildup Case)

Late-Time Cartesian Plot ("Muskat Plot"): Pressure Buildup Case