Borehole Pressuremeter Testing for In-Situ Static Bulk Modulus
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Solution Overview
Problem
There is no established method for measuring the static bulk modulus (K) of rock formations in situ, and existing methods are time-consuming and costly, often compromising results due to core sampling and laboratory testing.
Innovation Solution
A method and system using a wireline formation tester (WFT) tool with a packer and sensors to measure parameters during actuation in a borehole, incorporating additional metrics like strain, tilt, and stress to estimate the static bulk modulus (K) of geological formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If core sampling and laboratory testing are used to measure static bulk modulus, then measurement precision is improved, but loss of time and loss of substance occur
Solution Approach 1:
The patent replaces the mechanical core sampling and laboratory testing system with an in-situ pressuremeter testing system. The pressuremeter device is deployed directly in the borehole to measure formation properties, eliminating the need to extract cores and transport them to laboratories. This substitution of measurement methodology directly addresses the time loss associated with core sampling and lab testing while maintaining measurement accuracy through direct in-situ measurement.
Solution Approach 2:
The pressuremeter testing system performs the measurement function self-service by directly measuring formation properties in the borehole without requiring external laboratory facilities. The device uses its own integrated sensors and actuation system to obtain the necessary data, eliminating the need for separate core samples and laboratory equipment. This self-service approach resolves the time loss by conducting all measurements in-situ during a single operation.
2Measurement precision
If core sampling and laboratory testing are used to measure static bulk modulus, then measurement precision is improved, but loss of substance occurs
Solution Approach 1:
The patent replaces the mechanical core sampling system with an in-situ pressuremeter testing system that measures formation properties without extracting rock material. The pressuremeter device interacts with the formation through controlled pressure application and deformation measurement, eliminating the need to remove and handle rock cores. This substitution prevents the material damage that occurs during coring operations and subsequent laboratory processing.
3Ease of operation
If standard pressuremeter test is used to measure shear modulus, then ease of operation is improved, but measurement precision for bulk modulus deteriorates
Solution Approach 1:
The patent enhances the pressuremeter device to perform multiple measurement functions: it can measure both the shear modulus (G) and the bulk modulus (K) using the same in-situ testing methodology. By incorporating additional sensors and analysis capabilities that utilize the existing pressuremeter infrastructure, the system achieves universal measurement capability without requiring separate specialized devices. This multi-functionality maintains ease of operation while adding bulk modulus measurement precision.
Solution Approach 2:
The patent extends the measurement capability by analyzing additional dimensional data from the pressuremeter test. Beyond the traditional pressure-volume curve analysis used for shear modulus, the system incorporates measurements of packer deformation, borehole geometry changes, and stress distribution to derive bulk modulus information. This addition of measurement dimensions enables simultaneous determination of both G and K using the same operational framework.
4Measurement precision
If additional sensors and parameters are incorporated to measure bulk modulus, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent achieves bulk modulus measurement capability through multi-functionality of the existing pressuremeter system rather than adding entirely new measurement devices. The same packer actuation and pressure control infrastructure is utilized, with additional analysis of deformation and stress data to extract bulk modulus information. This approach improves measurement precision while minimizing the increase in device complexity by leveraging existing components for dual-purpose measurement.
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 efficient in situ measurement of K, reducing time and costs, and providing data for improved geomechanical modeling and safer drilling operations.
Implementation Method 1
the pressuremeter induces uniform radial expansion of an infinitely long cylinder... the measured formation stiffness (i.e., slope of the pressure versus volume curve) in the elastic deformation regime
Implementation Method 2
measuring one or more parameters of the packer and one or more parameters associated with a deformation of the borehole wall... parameters like strain, tilt, or stress
Data Source
AI summary
A method including obtaining measurements of one or more first parameters of a packer during an actuation of the packer in a borehole, obtaining measurements of one or more second parameters related to a geometrical change in the borehole caused by the actuation of the packer, and analyzing a plurality of first and second parameters, a plurality of derivatives of the first and second parameters, or a combination thereof to estimate at least a static bulk modulus (K) of a geological formation surrounding the borehole.