Full Immersion Pressure-Pulse Decay for Simultaneous Permeability
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Solution Overview
Problem
Current methods for measuring permeability in ultra-low permeability geologic formations, such as shales, are either time-consuming and accurate or rapid but lacking in reproducibility, and none can simultaneously determine permeabilities parallel and perpendicular to native bedding planes from a single test.
Innovation Solution
The full immersion pressure-pulse decay method, which applies a pressure pulse to the entire outer surface of a cylindrical core sample, allowing simultaneous measurement of radial and axial permeabilities and porosity, reducing experimental time significantly while ensuring accuracy and reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pressure-pulse decay methods are used on whole-core samples, then measurement accuracy is maintained, but experimental time becomes excessively long
Solution Approach 1:
The invention segments the pressure pulse application process by introducing a reference volume that is rapidly pressurized to create a controlled pressure pulse, while the sample volume remains at equilibrium pressure. This segmentation allows the pressure pulse to be applied instantaneously to the sample through the valve mechanism, enabling fast measurement without compromising accuracy.
2Productivity
If the GRI method is used with crushed cuttings, then experimental time is reduced, but measurement reproducibility and accuracy are compromised
Solution Approach 1:
The invention creates a universal measurement system that can handle both whole-core samples and crushed cuttings using the same apparatus and methodology. The key is that the pressure pulse decay principle remains universal, but the system is optimized to work best with whole-core samples where the geometry is well-defined, thereby achieving both speed and reproducibility.
3Adaptability or versatility
If a single test is performed on a cylindrical core sample, then all permeability parameters can be determined simultaneously, but the experimental setup becomes more complex
Solution Approach 1:
The invention utilizes the asymmetric geometry of the cylindrical core sample with defined length L and radius R to create distinct flow paths. By applying pressure pulse to the entire outer surface, the system exploits the asymmetric dimensions to simultaneously determine radial permeability (dependent on radius R) and axial permeability (dependent on length L), as well as porosity, from a single test.
4Measurement precision
If conventional methods are used to measure ultra-low permeability formations, then measurement fidelity is maintained, but turnaround time becomes unreasonably long
Solution Approach 1:
The invention employs periodic action through the rapid pressurization and depressurization cycles of the valve mechanism. The valve is opened to apply a pressure pulse, then closed to allow decay, creating a periodic measurement cycle that can be repeated quickly. This periodic action enables multiple measurements to be performed in the time it would take to perform one conventional measurement, thereby improving productivity while maintaining fidelity.
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 method enables rapid and accurate determination of permeabilities and porosity in both radial and axial directions from a single test, overcoming the limitations of existing techniques by reducing experimental time by an order of magnitude and providing reliable data for industrial applications.
Implementation Method 1
applying a pressure pulse to the reservoir and the entire outer surface area of the sample, wherein the pressure pulse increases the pressure in the reservoir to a pressure greater than the equilibrated pressure p0
Implementation Method 2
obtaining data representative of a pressure decay over time in the reservoir after application of the pressure pulse
Implementation Method 3
the sample is placed in a sealed reservoir containing a permeant such that the entire outer surface of the sample is exposed to the permeant
Implementation Method 4
applying a pressure pulse to the reservoir and the entire outer surface area of the sample, wherein the pressure pulse increases the pressure in the reservoir to a pressure greater than the equilibrated pressure p0
Data Source
AI summary
The present disclosure provide a method and apparatus for pressure-pulse decay performed on whole cylindrical samples whose entire outer surface areas are eligible to receive the pulse. Using the methods and apparatus of the present disclosure, not only is the experimental time dramatically shortened, it also allows for simultaneous determination of local permeabilities parallel and perpendicular to their native bedding planes. Currently, there is no permeability-measurement technique to capable of doing so from a single sample from a single test.