PART I – PRESSURE DRAWDOWN TEST (+VIDEO: Basic WTA)
1. Diffusivity Equation
2. Dimensionless Diff. Eq.
3. Line Source Solution
4. Skin Factor, Flow Efficiency, DR
5. Wellbore Storage
6. Reservoir Limit Test, Pseudo
...
PART I – PRESSURE DRAWDOWN TEST (+VIDEO: Basic WTA)
1. Diffusivity Equation
2. Dimensionless Diff. Eq.
3. Line Source Solution
4. Skin Factor, Flow Efficiency, DR
5. Wellbore Storage
6. Reservoir Limit Test, Pseudo-Steady State Flow Regime
7. Average Reservoir Pressure
8. Exercises
PART II – PRESSURE BUILDUP TEST
1. Horner Plot, Skin Factor
2. Flow Efficiency, DR
3. Wellbore Storage
4. Reservoir Limit Test, Pseudo-Steady State Flow Regime
5. Average Reservoir Pressure
6. Exercises
PART III – BUILDUP TEST PRECEDED BY VARIABLE RATE
PART IV – Not All Production Problems Can Be Diagnosed by the Skin Factor
PART IV – Multi-Layered Reservoirs
PART VI – DST
CONTENT OF CHAPTER 1
3INTRODUCTION
4The tools of reservoir characterization are:
1 - FORMATION EVALUATION
(a) – PETROPHYSICS (Core Analysis + Well log Interpretation)
(b) - Well Test Analysis
(d) - MWD (Measuring While Drilling), and
(e) - Borehole Geophysics
2 – GEOSTATISTICS
3 - SEDIMENTOLOGICAL INTERPRETATION
4 - 3D SEISMICS, 4D
5 - RESERVOIR SIMULATION
5Main reason different tools may yield
different result: SCALE
(WTA)
(3D seismics)
6APPLICATIONS OF PRESSURE TRANSIENT TESTS
Productivity tests are conducted to:
1. Determine well deliverability
2. Characterize formation damage and other sources of skin effect
3. Identify produced fluids and determine their respective volume ratios
4. Measure reservoir pressure and temperature
5. Obtain representative fluid samples suitable for PVT analysis
6. Evaluate completion efficiency
7. Evaluate workover or stimulation treatments.
Descriptive reservoir tests are conducted to:
1. Assess reservoir extent and geometry
2. Determine hydraulic communication between wells
3. Characterize reservoir heterogeneities
4. Evaluate reservoir parameters.
7Flow
Test Buildup
Test
t ∆t
t Pwf, psia
0.017 5868.0
0.019 5846.0
0.022 5833.0
0.026 5792.0
0.030 5765.0
0.035 5721.0
0.040 5688.0
0.046 5643.0
∆t, hr Pws, psia
0 3534
0.01 3544
0.02 3554
0.04 3574
0.06 3594
0.08 3614
0.1 3634
0.15 3680
t
p
Drawdown Buildup
8
t ∆t
P
wf(∆t=0)PART 1.1
–
PRESSURE DRAWDOWN
TEST
910
STRADDLE PACKER DST
BASIC WELL TEST SET-UPThe most basic equation to practically all pressure transient tests is the
diffusivity equation, which describes the radial flow of fluids through porous
media.
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