Deep Shale Adsorption Data via Molecular Dynamics Simulation
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Solution Overview
Problem
Conventional experimental test conditions cannot provide the high-pressure environment needed for accurate determination of deep shale gas adsorption data, making it difficult to obtain comprehensive adsorption characteristics across a full pressure range.
Innovation Solution
A method combining experimental tests and molecular dynamics models to determine adsorbed gas content in deep shale. This involves obtaining core samples, performing tests at various temperatures in a first-class pressure environment, establishing and adjusting molecular dynamics models, and using these models to simulate adsorption data in a second-class pressure environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional experimental test conditions are used, then the testing process is simple and equipment requirements are met, but the high-pressure environment needed for deep shale gas adsorption data cannot be provided
Solution Approach 1:
The patent introduces molecular dynamics simulation as an intermediary method to bridge the gap between conventional experimental conditions and deep shale high-pressure environments. The simulation acts as a mediator that can model adsorption behavior under ultra-high pressures (up to 100 MPa) that are difficult to achieve experimentally, while still providing quantitatively accurate results that can be validated against available experimental data.
Solution Approach 2:
The patent changes the pressure parameter range from conventional experimental limits to ultra-high pressure conditions (0-100 MPa) through molecular dynamics simulation. By adjusting simulation parameters such as pressure, temperature, and gas composition, the method can accurately predict adsorption characteristics under deep shale reservoir conditions that exceed conventional testing capabilities.
2Measurement precision
If experimental tests are performed to obtain adsorption data, then the data is obtained through direct measurement, but the full pressure range coverage is insufficient due to equipment limitations
Solution Approach 1:
The patent performs preliminary calibration of the molecular dynamics model using experimental adsorption data obtained at lower pressures and temperatures. This preliminary action establishes the accuracy and reliability of the simulation model before extending it to predict adsorption behavior under ultra-high pressure conditions, ensuring that the extended predictions are grounded in experimentally validated parameters.
Solution Approach 2:
The patent creates a virtual copy of the shale rock matrix and gas adsorption system through molecular dynamics simulation. This digital replica allows for the exploration of the full pressure range (0-100 MPa) without the physical constraints of experimental equipment, while maintaining quantitative accuracy by calibrating the simulation against real experimental data points.
3Adaptability or versatility
If molecular dynamics models are used to simulate high-pressure adsorption, then the full pressure range can be covered, but the model establishment and adjustment process becomes complex
Solution Approach 1:
The patent segments the pressure range into two distinct classes: first-class pressure environment (conventional experimental range) and second-class pressure environment (ultra-high pressure range). This segmentation allows for different methodologies to be applied to each range - experimental methods for the first class and molecular dynamics simulation for the second class - thereby managing complexity by dividing the problem into manageable parts with appropriate solution strategies.
Solution Approach 2:
The patent uses partial experimental data (at lower pressures) to calibrate and validate the molecular dynamics model, then uses this partially validated model to predict the excessive pressure range (ultra-high pressures) that cannot be experimentally accessed. This partial action approach reduces the complexity burden by not requiring complete experimental coverage of all pressure conditions.
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 the acquisition of accurate and comprehensive adsorption characteristic curves across a full pressure range by integrating data from both first-class and second-class pressure environments, overcoming the limitations of conventional experimental methods.
Implementation Method 1
shale gas is usually stored in free and adsorbed states in dark mud shale or high carbon mud shale, wherein the adsorbed state (i.e., the adsorbed gas) is the main occurrence form of the shale gas
Implementation Method 2
establishing a first shale molecular dynamics model for the core sample; adjusting the first shale molecular dynamics model based on the shale gas adsorption data
Data Source
AI summary
A method and apparatus for determining content of adsorbed gas in a deep shale, and a server, wherein experimental tests are combined with molecular dynamics models. Firstly, tests are performed on a core sample of a target area at various temperatures in a first-class pressure environment with low pressure to obtain shale gas adsorption data of the core sample; next, a first shale molecule dynamics model of the core sample is established, and a fitting adjustment is performed on the first shale molecule dynamics model using the shale gas adsorption data to obtain a second shale molecule dynamics model. Further, the second shale molecular dynamics model is used to obtain, by analogue simulation, shale gas adsorption data of the core sample corresponding to the various temperatures in a second-class pressure environment with high pressure, so as to obtain an accurate and comprehensive adsorption characteristic curve in a full pressure range.