Dynamic Acousto-Elasticity Apparatus for Subsurface Pressure Characterization
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Solution Overview
Problem
Current methods for characterizing formation pore pressure are limited by the need for direct formation contact, high costs, and scarcity of accurate data, particularly in cased and open hole environments, with existing techniques restricted to ambient pressure conditions.
Innovation Solution
The development of a dynamic acousto-elasticity technique apparatus that measures nonlinear elasticity parameters at controlled internal fluid pore pressures and external confining stress conditions, allowing for reliable rock formation fluid pore pressure characterization without direct formation contact, using a flow-through triaxial pressure vessel and dynamic acousto-elasticity technique to induce and probe strain fields in rock samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct formation probe contact methods are used for pore pressure measurement, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces direct mechanical contact probe systems with an acoustic wave-based measurement system. Acoustic transducers generate and detect acoustic waves that propagate through the formation, allowing pore pressure measurement without physical probe contact. This substitution of mechanical contact with acoustic field interaction resolves the contradiction by maintaining measurement capability while eliminating the complexity of direct contact probe assemblies.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium between the measurement system and the formation. Instead of direct probe-formation contact, acoustic waves serve as the mediator that carries information about pore pressure from the formation to the detectors. This intermediary approach enables indirect measurement, reducing device complexity while preserving measurement accuracy.
2Reliability
If direct formation probe contact methods are used, then measurement reliability is improved, but loss of time and productivity worsen due to wire line probe assembly risks
Solution Approach 1:
By replacing the mechanical wire line probe assembly system with an acoustic wave-based system, the patent eliminates the risks associated with probe deployment and retrieval. The acoustic measurement system can be implemented through existing wellbore infrastructure, removing the time-consuming and risky wire line operations while maintaining or improving measurement reliability.
Solution Approach 2:
The patent extracts the measurement function from the physical probe assembly and implements it through acoustic wave propagation. This separation allows the measurement capability to be decoupled from the complex deployment and retrieval operations, eliminating the time losses and risks associated with wire line probe assembly while preserving measurement reliability.
3Device complexity
If ambient pressure conditions are used for elasticity parameter measurement, then device complexity is reduced, but adaptability to subsurface conditions worsens
Solution Approach 1:
The patent designs a pressure vessel system that can simulate various subsurface pressure conditions while maintaining a relatively simple overall structure. The pressure vessel serves multiple functions: it contains the formation sample, applies controlled confining pressure, maintains pore pressure, and provides a controlled environment for acoustic measurements. This multi-functionality achieves adaptability to subsurface conditions without proportionally increasing device complexity.
Solution Approach 2:
The patent implements the ability to change pressure parameters (confining pressure and pore pressure) to simulate different subsurface conditions. By controlling these physical parameters in the pressure vessel, the system can adapt to various formation conditions without requiring fundamentally different measurement systems, thus achieving versatility while managing complexity through parameter control rather than structural complexity.
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
Enables accurate and reliable measurement of nonlinear elasticity parameters at simulated subsurface conditions, facilitating the development of downhole tools for pore pressure characterization in cased and open hole environments, improving data availability and reducing costs.
Implementation Method 1
dynamic acousto-elasticity technique measurements at simulated subsurface pressures
Implementation Method 2
measuring nonlinear parameters at controlled sample internal fluid pore pressures and external confining stress conditions
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
An apparatus (10) and method for performing nonlinear elasticity measurements using the dynamic acousto-elasticity technique (DAET) at simulated subsurface conditions in the laboratory, are described. The current state-of-the-art for measuring nonlinear elasticity parameters using DAET is limited to ambient pressure conditions on the bench-top. The present invention permits nonlinear parameter measurements at controlled sample internal fluid pore pressures (52) and external confining stress (44), (50) conditions.