Petroleum Material Balance Gas Calculator
Fit actual dry gas p/z versus cumulative production material balance, not EOS Z inference, volumetric OGIP or a gas reserve claim. Caller independently verifies units, applicability and matching conditions; no operational recipe, safety certification, causal efficacy or legal/resource classification is inferred.
Description
For a verified closed dry-gas balance, pressure divided by gas Z factor can be fitted against cumulative stock production.
For a verified closed dry-gas balance, pressure divided by gas Z factor can be fitted against cumulative stock production.1
This tool uses the supplied Z observations and extrapolated line intercept to calculate the reduced balance’s original gas volume.
When to use Petroleum Material Balance Gas 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 Material Balance Gas 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 observedCumulativeProducedStockGasM3, observedReservoirPressuresPa, observedMatchedGasZFactors, callerClosedDryGasBalanceVerified, following the field table and calculation rules below, then run the tool.
- Read fittedPOverZInterceptPa, dryGasBalanceOriginalStockM3, dryGasBalanceFitRSquared. 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 |
|---|---|---|---|
| observedCumulativeProducedStockGasM3 | Observed cumulative produced stock gas m3 | list of number | Required |
| observedReservoirPressuresPa | Observed reservoir pressures pa; pressure or stress in pascals, with the sign convention described above. | list of number | Required |
| observedMatchedGasZFactors | Observed matched gas z factors | list of number | Required |
| callerClosedDryGasBalanceVerified | Caller closed dry gas balance verified | boolean | Required |
Require nonempty aligned nonnegative cumulative stock production and positive pressures and Z factors, with callerClosedDryGasBalanceVerified=true. Fit p/z against production using at least two pairs with nonzero predictor variance. Require a negative fitted slope and return −intercept/slope, intercept, and R². Closed, constant-temperature conditions without influx or injection are caller assertions; Z is not calculated from an equation of state.
The regression helper accepts 2–10000 aligned finite pairs with nonzero predictor variance. It fits ordinary least squares with a free intercept using shifted coordinates; samples need not be sorted unless this tool additionally requires it. R² is clamped to [0,1] and is one for constant responses. Transformed fits use the stated predictor/response basis. Only fields present in this tool’s output are returned; an internal R² calculation does not add an undocumented output. R² is a fit summary rather than a confidence interval.
p/z≈intercept+slope×Gp; G=−intercept/slope Read these symbols with the field meanings and branch or reference rules above.
| Output field | Meaning | Value type |
|---|---|---|
| fittedPOverZInterceptPa | Fitted p over z intercept pa; pressure or stress in pascals, with the sign convention described above. | number |
| dryGasBalanceOriginalStockM3 | Dry gas balance original stock m3 | number |
| dryGasBalanceFitRSquared | Dry gas balance fit r squared | number |
{
"input": {
"observedCumulativeProducedStockGasM3": [
0,
1,
2
],
"observedReservoirPressuresPa": [
10,
9,
8
],
"observedMatchedGasZFactors": [
1,
1,
1
],
"callerClosedDryGasBalanceVerified": true
},
"output": {
"fittedPOverZInterceptPa": 10,
"dryGasBalanceOriginalStockM3": 10,
"dryGasBalanceFitRSquared": 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 Original Gas In Place OGIP Calculator: Original in-place stock volume can be estimated by summing independently delineated reservoir patches. This gas calculator uses area, net thickness, porosity, water saturation, and a matched formation-volume factor for each nonoverlapping patch. For a complementary step, use Petroleum Recovery Factor Gas Calculator: Observed gas recovery compares cumulative stock production with an independently established original inventory. This audit also reconciles a separate remaining inventory, keeping ratios above one and signed discrepancies visible.
References
Similar or alternative tools
- Petroleum Original Gas In Place OGIP Calculator
Original in-place stock volume can be estimated by summing independently delineated reservoir patches. This gas calculator uses area, net thickness, porosity, water saturation, and a matched formation-volume factor for each nonoverlapping patch.
- Petroleum Recovery Factor Gas Calculator
Observed gas recovery compares cumulative stock production with an independently established original inventory. This audit also reconciles a separate remaining inventory, keeping ratios above one and signed discrepancies visible.