Adaptive Pressure Pulse Testing for Reservoir Characterization
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Solution Overview
Problem
Conventional formation pressure testing methods require extensive time, especially for low mobility reservoirs like shale gas and heavy oil, leading to loss of valuable drilling rig time and increased costs.
Innovation Solution
Adaptive pressure pulse testing techniques are applied, where pre-job simulations are conducted to optimize pulse test parameters, reducing testing time by determining reservoir pressure and permeability in less than an hour, and further analyzed with optimization methods and inverse algorithms to yield more information about reservoir properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single drawdown/buildup testing is performed, then accurate formation pressure and permeability data can be obtained, but the testing time becomes excessively long (several hours or days)
Solution Approach 1:
The patent applies periodic action by implementing pressure pulsing instead of continuous drawdown. The system performs repeated cycles of drawdown and pressure recovery, where the piston moves back and forth to create periodic pressure fluctuations. This periodic action accelerates the testing process by continuously stimulating fluid flow from the formation, reducing stabilization time from hours/days to minutes while maintaining measurement accuracy through multiple measurement cycles during the pulsing sequence.
Solution Approach 2:
The patent applies preliminary action by performing multiple drawdown/buildup cycles before final stabilization. Instead of waiting for natural stabilization after a single drawdown, the system performs preliminary pressure pulsing cycles that progressively condition the formation interface and accelerate fluid flow. These preliminary actions prepare the system for faster final measurement by pre-establishing flow pathways and reducing resistance at the wellbore interface.
2Productivity
If pressure pulsing is implemented to reduce testing time, then testing duration is significantly reduced, but the complexity of the testing procedure increases
Solution Approach 1:
The patent applies self-service by implementing automated control of the pressure pulsing sequence. The system automatically manages the complex multi-stage testing procedure, including automatic piston positioning, pressure monitoring, and sequence coordination. This automation handles the procedural complexity internally, allowing the system to deliver high productivity through sophisticated pressure pulsing while minimizing the operational burden on users. The controller autonomously manages the testing sequence based on pre-programmed parameters.
Solution Approach 2:
The patent applies feedback by continuously monitoring pressure responses during each phase of the pulsing sequence and using this information to adjust subsequent pulses. The system measures pressure at multiple points during drawdown, buildup, and stabilization phases, then uses this feedback to optimize the timing and magnitude of subsequent pressure pulses. This feedback mechanism allows the complex procedure to adapt to actual formation conditions, improving both efficiency and accuracy while managing complexity through intelligent control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces formation pressure testing time and cost by adaptively determining flow rates based on pressure responses during each phase of the pulse test, allowing for more efficient determination of reservoir properties.
Implementation Method 1
The volume of the sample chamber may be increased or decreased by translating a piston within the cylinder
Implementation Method 2
pressure recorders measure and record the fluid pressure transients
Data Source
AI summary
A system for pressure testing a formation includes a downhole tool configured to measure formation pressure, storage containing pressure parameters of a plurality of simulated formation pressure tests, and a formation pressure test controller coupled to the downhole tool and the storage. For each of a plurality of sequential pressure testing stages of a formation pressure test, the formation pressure test controller 1) retrieves formation pressure measurements from the downhole tool; 2) identifies one of the plurality of simulated formation pressure tests comprising pressure parameters closest to corresponding formation pressure values derived from the formation pressure measurements; and 3) determines a flow rate to apply by the downhole tool in a next stage of the test based on the identified one of the plurality of simulated formation pressure tests.