Shale Oil Soaking Time Determination via CT Core Analysis
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Solution Overview
Problem
Current methods for determining the optimal soaking time after volume fracturing of shale oil reservoirs lack a theoretical basis, leading to inefficient production due to either inadequate stimulation or reservoir damage, and struggle to evaluate production potential along horizontal well sections.
Innovation Solution
A method involving core processing, saturated oil treatment, CT scanning, immersion in fracturing fluid, and digital core technology to calculate the weight of newly added fracture porosity-fillable fracturing fluid, identifying the optimal soaking time by intersecting curves of core mass increase and fracturing fluid weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If soaking time is determined based on engineering experience, then the process is simple and quick, but the determination lacks theoretical basis and leads to inefficient production
Solution Approach 1:
The patent creates a physical model (core column) that copies the essential characteristics of the shale oil reservoir, allowing laboratory-scale experiments to represent field conditions. This enables accurate soaking time determination through controlled experiments rather than relying on empirical experience, resolving the contradiction between accuracy and complexity by using a simplified but representative physical analog.
Solution Approach 2:
The patent replaces subjective engineering experience with objective scientific measurement methods, specifically CT scanning technology to quantify fracture porosity changes. This substitution of mechanical/experiential judgment with precise instrumental measurement achieves accurate soaking time determination while maintaining manageable experimental complexity through standardized procedures.
2Productivity
If soaking time is too short, then the process is efficient and quick, but the stimulation effect is poor
Solution Approach 1:
The patent implements a feedback mechanism by using CT scanning to continuously monitor fracture porosity changes during the soaking process. This allows real-time detection of when the soaking effect reaches its maximum, providing an objective criterion for determining the optimal soaking time that balances production stimulation with time efficiency, avoiding both insufficient and excessive soaking durations.
3Reliability
If soaking time is too long, then the stimulation effect is maximized, but serious damage is caused to the reservoir
Solution Approach 1:
The patent performs preliminary characterization of the core column using CT scanning before the soaking experiment to establish baseline fracture porosity. This preliminary action allows for precise monitoring of changes during soaking and enables early termination when optimal results are achieved, preventing reservoir damage from excessive soaking while ensuring maximum stimulation effect is obtained.
4Adaptability or versatility
If horizontal well section penetrates multiple shale oil reservoirs, then the well coverage is maximized, but evaluating production potential at different positions becomes difficult
Solution Approach 1:
The patent applies segmentation by dividing the horizontal well section into multiple discrete core samples representing different reservoir positions. Each core is independently evaluated through the soaking experiment and CT scanning process, allowing production potential to be assessed for each segment separately. This segmented approach enables detailed positional analysis while maintaining overall well coverage, resolving the contradiction between comprehensive coverage and evaluation difficulty.
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 provides a theoretically grounded and efficient means to determine the optimal soaking time, enhancing production potential by accurately assessing the production potential of shale oil reservoirs and guiding optimal soaking time decisions.
Implementation Method 1
immersing the core column after the CT scanning experiment into fracturing fluid at the temperature of the target reservoir and the pressure condition of the target reservoir, and testing a core mass increase amount of the core column at different immersion durations
Implementation Method 2
performing a CT scanning experiment on the core column after the saturated oil treatment, and obtaining an initial fracture porosity parameter of the core column combined with a digital core technology
Data Source
AI summary
A method for evaluating a production potential for volume fracturing of a shale oil reservoir and determining a soaking time is discloses. The method may comprise: obtaining a core column; performing a saturated oil treatment on the core column; obtaining an initial fracture porosity parameter of the saturated oil-treated core column; soaking the core column after a CT scanning into a fracturing fluid to test the core mass increase amount at different immersion durations; obtaining the fracture porosity increase amount of the core column at different soaking times, and calculating a weight of newly added fracture porosity-fillable fracturing fluid; generating a curve of the core mass increase amount and a curve of the weight of the newly added fracture porosity-fillable fracturing fluid at different immersion durations; comparing a mass increase amount per volume unit of a core, and ranking a e mass increase amount per volume unit of the core to determine the production increase potential.