Shale Oil Core Holder with Microinjector for Pressure Gradient
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Solution Overview
Problem
Conventional core holders are inadequate for accurately measuring the movable oil volume and starting pressure gradient of low-porosity, low-permeability, and small-volume shale rock samples due to limited length change range and high measurement errors, making it difficult to assess shale oil mobility effectively.
Innovation Solution
A core holder with an inlet plug, outlet plug, and core accommodating cavity, equipped with a microinjector and rubber gasket, allowing for precise measurement of shale oil volume and calculation of starting pressure gradient through a prediction method involving correlation indices and physical data analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional core holders are used for shale oil mobility measurement, then the device structure is simple and easy to manufacture, but the measurement precision of movable oil volume and starting pressure gradient is insufficient
Solution Approach 1:
The core holder is divided into multiple functional segments: core accommodating cavity for sample placement, microinjector system for precise fluid injection, rubber gasket for sealing, and pressure measurement components. This segmentation allows each part to be optimized for its specific function, improving overall measurement precision while maintaining manufacturing feasibility through modular assembly
Solution Approach 2:
The core holder is designed as a multi-functional device that can perform multiple measurements: movable oil volume measurement, starting pressure gradient determination, and core plug sealing. The microinjector system serves both injection and measurement functions, reducing the need for separate specialized equipment while enhancing measurement capabilities
2Measurement precision
If conventional core holders are used for shale oil mobility measurement, then the device is easy to manufacture, but the measurement errors are large and cannot accurately measure low-porosity and low-permeability samples
Solution Approach 1:
The design replaces conventional mechanical measurement systems with a microinjector-based system that uses controlled fluid injection and pressure measurement. This substitution enables precise measurement of starting pressure gradient in low-porosity, low-permeability shale samples by measuring the pressure required to initiate fluid flow through the core plug, rather than relying on mechanical displacement methods
Solution Approach 2:
The core holder enables measurement under controlled parameter changes including pressure, temperature, and injection rate. By systematically varying these parameters and measuring the corresponding fluid flow responses, the device can accurately determine starting pressure gradient for different shale samples with varying porosity and permeability characteristics
3Length of moving object
If conventional core holders are used, then the length change range is small, but the measurement errors are large
Solution Approach 1:
The microinjector acts as an intermediary device between the pressure system and the core plug. It enables precise measurement of small volume changes by injecting known volumes of fluid and measuring the pressure response, thereby amplifying the detectable signal from small length changes in low-permeability samples and improving measurement precision
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
The core holder enables accurate measurement of shale oil mobility and starting pressure gradient, improving experimental precision and suitability for unconventional oil reservoirs, particularly shale oil, with reduced measurement errors and enhanced operational ease.
Implementation Method 1
a microinjector, a needle portion of the microinjector being used to pass through the outlet plug and the rubber gasket in sequence to contact the shale oil disposed in the core accommodating cavity
Data Source
AI summary
A core holder and a prediction method for starting pressure gradient of shale oil based on the core hold are provided. The core holder includes an inlet plug, an outlet plug, a core accommodating cavity disposed between the inlet plug and the outlet plug and used for accommodating the shale oil, a rubber gasket disposed between the outlet plug and the core accommodating cavity, and a microinjector including a microinjector needle portion that passes through the outlet plug and the rubber gasket in sequence to be in contact with the shale oil in the core accommodating cavity. The core holder and the method can solve problems that movable oil volume of a low-porosity, low-permeability and small-volume rock sample and a shale rock sample cannot be accurately measured, and that a movable scale and a starting pressure gradient of the shale oil cannot be measured.