Formation Pressure Determination Using Derivative Analysis
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Solution Overview
Problem
Conventional computer-based systems for analyzing oil and gas reservoirs provide limited reservoir characteristics, requiring interpretation by oil and gas professionals and struggling to accurately determine formation pressure due to factors like wellbore conditions and data acquisition tool positioning.
Innovation Solution
A data processing system that receives measurement data from various data acquisition tools, analyzes it to identify pressure derivative responses, and adjusts the last-read pressure to determine accurate formation pressures, accounting for factors like permeability and tool positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional computer-based systems are used to analyze reservoir characteristics, then data processing can be performed, but the systems provide limited reservoir characteristics requiring interpretation by professionals and struggle to accurately determine formation pressure
Solution Approach 1:
The patent introduces a computer-based system with automated algorithms that act as an intermediary between raw measurement data and professional interpretation. The system processes pressure transient data, identifies flow regimes, and determines reservoir characteristics automatically, reducing the need for manual professional interpretation while improving accuracy and information completeness
Solution Approach 2:
The system transforms raw measurement data into meaningful reservoir characteristics by changing parameters from simple pressure readings to derived quantities such as permeability, skin factor, and formation pressure. This parameter transformation enables automated determination of formation pressure by analyzing pressure derivative responses and identifying characteristic flow regime patterns
2Productivity
If automated computer-based analysis is implemented, then productivity increases, but measurement precision of formation pressure deteriorates due to wellbore conditions and tool positioning factors
Solution Approach 1:
The system incorporates feedback mechanisms by analyzing pressure derivative responses and comparing them against theoretical models of different flow regimes. The automated algorithms continuously refine formation pressure determination by feedback from the pressure transient data patterns, accounting for wellbore storage effects and tool positioning factors to maintain accuracy while improving productivity
Solution Approach 2:
The system performs preliminary analysis of pressure transient data to identify flow regime transitions and characteristic patterns before final formation pressure determination. By pre-processing the data to recognize spherical, radial, and linear flow regimes, the system prepares corrected pressure values that account for wellbore conditions, enabling both high productivity and precision
Data Source
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AI summary
A method, apparatus, and program product for determining a formation pressure for a reservoir. Measurement data for a pretest of a formation of the reservoir is received. The measurement data is analyzed to determine a last-read event and a corresponding last-read pressure. Derivative data for flow regime identification is determined based at least in part on the measurement data. The derivative data is analyzed to determine a pressure derivative response, and a formation pressure is determined based at least in part on the last-read event, the last-read pressure, and the pressure derivative response.