Minimization Of The Noise In The Calculated Pressure Derivative Data For The Interpretation Of Transient Tests

Date

2023-09-29

Author

Coşar, Doğuhan
Sınayuç, Çağlar

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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Well tests are conducted to estimate essential reservoir parameters like permeability and skin factor. Pressure data is recorded at regular intervals during these tests, which are crucial for predicting the production potential of oil or gas. Analyzing pressure changes provides insights into the reservoir's characteristics and its ability to produce hydrocarbons over time.Three different cases of drawdown tests are examined, and derivative curves are plotted using data points separated by specific intervals, ranging from 0.10 to 0.50 of a log cycle. This interval selection is vital to avoid excessively noisy derivative values during differentiation. A novel method is developed to determine the log cycle interval that minimizes noise while maintaining the integrity of the derivative curve. Additionally, second and third derivatives are calculated for each log cycle interval to identify the most suitable one. The log cycle interval helps identify early, middle, and late-time regions, representing different flow regimes in both cases. The data from the middle time region is selected for the estimation process, as it offers the best estimates of permeability. These results are then compared with those obtained from KAPPA's Saphir Module, an industry-standard PTA (pressure transient analysis) module. The Python code used for estimation is found to provide more accurate estimations of permeability and skin factor and can handle noises up to ±2.5%.

Subject Keywords

Derivative Plots, Pressure Transient Analysis

URI

https://hdl.handle.net/11511/107695

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Department of Petroleum and Natural Gas Engineering, Conference / Seminar