Common causes for data inconsistencies are as follows:
- Recompletion, reperf, refrac
- Fracture cleanup
- Wellbore cleanup
- Liquid loading
- Slugging
- Tubing change-out
- Changing flowpath
- Under-reported work-overs
- Incorrect pressure source and flow path
- Pressure or rate averaging
- Out of sync pressure and rate time-tracks
- Missing flowing pressures or rates
- Incorrect initial pressure
- Misreported water production
- Significant increase in water gas ratio (WGR)
Use the flowchart below to evaluate the quality of your data:
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Start pre-analysis diagnostics here
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Do the instantaneous changes in pressure and rate correlate?
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See the step change correlation on the rate & pressure vs. time plot. |
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Is the well operating under high drawdown?
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See the drawdown plot. |
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Is the trend in rate and pressure consistent?
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See the trend correlation on the rate & pressure vs time plot. |
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Is the data smooth?
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See the stable data and continuous smooth data plots on the rate & pressure vs time plot. |
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Have the outliers been removed?
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See the continuous smooth data plot on the rate & pressure vs time plot. |
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Does the Blasingame graph continuously decline?
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See the Blasingame and NPI plots |
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Do the Blasingame or NPI plots contain a single continuous stem?
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See the Blasingame and NPI plots |
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Does the FMB rate plot trend decline?
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See the FMB rate and FMB pressure plots |
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Do the FMB rate or pressure plots have a single continuous stem?
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See the FMB rate and FMB pressure plots |
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Is the gas rate above the critical Turner rate?
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See the Turner rate plot |
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Is the water rate reported?
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See the WGR & water rate plot |
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Is the water rate free of rapid increases?
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See the WGR & water rate plot |
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Is WGR free of rapid decreases?
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See the WGR & water rate plot |
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Is the gas rate on the log-log plot free of sharp declines?
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See the log gas rate plot |
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Finish. Proceed to analysis |
