Petroleum Well Test Skin Calculator
Extract transient test skin from observed minus independently matched zero-skin drawdown divided by2 natural-log derivative, distinct from pseudo-steady radius/.75 inverse; no damage diagnosis. Caller independently verifies units, applicability and matching conditions; no operational recipe, safety certification, causal efficacy or legal/resource classification is inferred.
Description
Transient well-test skin describes additional drawdown relative to a matched zero-skin reference under a radial-flow convention.
Transient well-test skin describes additional drawdown relative to a matched zero-skin reference under a radial-flow convention.1
This tool computes signed apparent skin from supplied traces and natural-log derivatives, without diagnosing formation damage.
When to use Petroleum Well Test Skin Calculator
Use this tool when you need to calculate the stated measurement summary or conditional model from matched observations. Prepare completed matched measurements, SI or explicitly stated oilfield units, and independent evidence for the selected branch or calibration.
How to use Petroleum Well Test Skin Calculator and understand its results
- Prepare completed matched measurements, SI or explicitly stated oilfield units, and independent evidence for the selected branch or calibration.
- Enter observedSelectedTestDrawdownPa, callerIndependentlyMatchedZeroSkinDrawdownPa, callerRadialNaturalLogDerivativePa, following the field table and calculation rules below, then run the tool.
- Read apparentTransientTestSkinFactors. For result objects, inspect the nested output fields below, including any missing evidence or selected indices.
- Correct any input issues and run again. Before using a successful result, review its units, signs, evidence coverage, and stated model or reference assumptions.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| observedSelectedTestDrawdownPa | Observed selected test drawdown pa; pressure or stress in pascals, with the sign convention described above. | list of number | Required |
| callerIndependentlyMatchedZeroSkinDrawdownPa | Caller independently matched zero skin drawdown pa; pressure or stress in pascals, with the sign convention described above. | list of number | Required |
| callerRadialNaturalLogDerivativePa | Caller radial natural log derivative pa; pressure or stress in pascals, with the sign convention described above. | list of number | Required |
Require nonempty aligned nonnegative observed and zero-skin drawdowns and strictly positive radial natural-log derivatives. Subtract the reference drawdown and divide by twice the derivative for every pair. Negative skin is retained.
skin_i=(observedDrawdown_i−zeroSkinDrawdown_i)/(2×naturalLogDerivative_i) Read these symbols with the field meanings and branch or reference rules above.
| Output field | Meaning | Value type |
|---|---|---|
| apparentTransientTestSkinFactors | Apparent transient test skin factors | list of number |
{
"input": {
"observedSelectedTestDrawdownPa": [
10,
12
],
"callerIndependentlyMatchedZeroSkinDrawdownPa": [
6,
8
],
"callerRadialNaturalLogDerivativePa": [
1,
2
]
},
"output": {
"apparentTransientTestSkinFactors": [
2,
1
]
}
}Limitations and assumptions
Measurements, unit conventions, branch identity, and model applicability must be independently established. The result does not infer a complete reservoir or flow model, operational settings, or a reserve classification.
Missing required fields, unknown fields, wrong types, and violated calculation rules return input issues. Numeric values must be finite; nonfinite numeric outputs are rejected. Arrays must be dense, with no missing cells. Numeric lists allow at most 10000 entries, subject to smaller tool-specific bounds above.
Alternative or Complementary methods
For a related task, use Petroleum Skin Factor Calculator: Pseudo-steady radial skin is an additional pressure-loss term relative to a specific drainage-radius model. This calculator inverts a supplied pressure scale and geometry while retaining negative apparent skin. For a complementary step, use Petroleum Pressure Derivative Calculator: Bourdet pressure derivatives summarize pressure change against natural log of elapsed time using neighboring intervals. This tool evaluates the three-point weighted derivative on unequal sample times and returns only interior observations.
References
-
Petroleum Well Test Skin Calculator — tool.io
Similar or alternative tools
- Petroleum Skin Factor Calculator
Pseudo-steady radial skin is an additional pressure-loss term relative to a specific drainage-radius model. This calculator inverts a supplied pressure scale and geometry while retaining negative apparent skin.
- Petroleum Pressure Derivative Calculator
Bourdet pressure derivatives summarize pressure change against natural log of elapsed time using neighboring intervals. This tool evaluates the three-point weighted derivative on unequal sample times and returns only interior observations.