Hypergravity Hydrate Reservoir Modeling for Fracture Stress Simulation
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Solution Overview
Problem
Current apparatuses for simulating natural gas hydrate reservoirs in hydraulic fracturing fail to accurately model large-scale reservoirs, neglecting geothermal gradients and overall formation stress distribution, and lack hydraulic fracturing simulation capabilities, leading to inefficient gas production.
Innovation Solution
A hypergravity experimental apparatus with a high-pressure vessel, water bath temperature control, effective stress control, fracturing reinforcement, and multi-physical field monitoring modules, capable of simulating large-scale hydrate reservoirs under hypergravity conditions, including temperature and stress control, fluid injection, and real-time monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If triaxial experimental apparatuses are used to simulate stress levels of centimeter-scale hydrate-bearing sediment, then specific stress condition simulation is achieved, but large-scale reservoir geothermal gradient and overall formation stress distribution cannot be simulated
Solution Approach 1:
The experimental apparatus is divided into multiple independent modules: a centrifuge module for gravitational field simulation, a temperature control module for geothermal gradient simulation, and a hydraulic fracturing module for fracture induction. Each module can independently control its parameters, allowing the system to simulate large-scale reservoir conditions while maintaining precise control over stress, temperature, and fracture characteristics.
Solution Approach 2:
The patent transitions from conventional triaxial testing (one-dimensional stress control) to a multi-dimensional simulation system that simultaneously controls gravitational stress (via centrifuge), temperature gradient (via heating/cooling plates), and hydraulic pressure (via injection systems). This multi-dimensional approach enables accurate simulation of large-scale reservoir conditions that cannot be achieved in traditional laboratory settings.
2Ease of operation
If conventional hydrate exploitation modeling apparatuses are used, then constant gravity conditions are maintained, but hydraulic fracturing simulation capability is lacking
Solution Approach 1:
The patent merges the centrifuge module (for gravity simulation) with the hydraulic fracturing module (for fracture induction) into a single integrated experimental system. This combination allows simultaneous simulation of hypergravity conditions and hydraulic fracturing processes, enabling study of fracture development under realistic reservoir stress states while maintaining stable gravity field control throughout the experiment.
Solution Approach 2:
The experimental apparatus is designed with multi-functionality to perform various operations including: centrifugal acceleration for stress simulation, temperature control for geothermal gradient simulation, hydraulic fluid injection for fracturing, and production well simulation. This universal design allows the same system to simulate complete hydrate exploitation processes from stress state to fracture induction to gas production.
3Strength
If hydraulic fracturing is applied to hydrate reservoirs with low strength and stiffness, then fracture induction is achieved, but fracture development and final distribution patterns cannot be accurately revealed
Solution Approach 1:
The patent introduces transparent or semi-transparent modeling materials with controlled mechanical properties as intermediaries between the fracturing system and the observation system. These specialized materials allow real-time visual observation of fracture development and distribution patterns while maintaining the necessary mechanical strength and stiffness characteristics of actual hydrate-bearing sediments. The materials serve as mediators that enable both fracture induction and accurate pattern observation.
Solution Approach 2:
The patent employs color-coded tracers, dyes, or contrast agents injected with the fracturing fluid that change color or become visible under specific conditions (such as UV illumination or temperature changes). This allows real-time visualization and accurate measurement of fracture propagation paths, branch development, and final distribution patterns within the reservoir model, providing precise data on fracture morphology under hypergravity conditions.
4Ease of operation
If existing apparatuses are used for hydrate exploitation simulation, then constant gravity conditions are maintained, but in-situ production efficiency cannot be accurately simulated
Solution Approach 1:
The patent employs a centrifuge system that can dynamically adjust rotational speed to create variable hypergravity conditions (e.g., 1g to 500g). This dynamic capability allows the system to simulate different depths and stress states within the reservoir, enabling accurate simulation of in-situ production efficiency under various gravitational conditions. The system can transition between different gravity levels to study fracture propagation and gas production under realistic reservoir 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
Accurately simulates the hydraulic fracturing and exploitation process of deep-sea hydrate reservoirs, revealing fracture development patterns and enhancing production efficiency by reproducing in-situ conditions, overcoming low permeability and stability issues.
Implementation Method 1
The high-pressure vessel, the effective stress control module, and the fracturing reinforcement exploitation module are all mounted within a centrifuge basket and operate under 1 g to 500 g hypergravity
Implementation Method 2
The high-pressure vessel is provided with a hydrate reservoir model inside and is entirely placed in a water bath environment and connected to the water bath temperature control module
Implementation Method 3
The fracturing reinforcement exploitation module communicates with the inside of the high-pressure vessel and conducts fracturing, reinforcement, and exploitation experiments on the hydrate reservoir model
Data Source
AI summary
A hypergravity experimental apparatus and method for natural gas hydrate exploitation by hydraulic fracturing are provided. A high-pressure vessel contains a hydrate reservoir model placed in a water bath environment connected to a water bath temperature control module. An effective stress control module applies stress control. A fracturing reinforcement exploitation module conducts fracturing, reinforcement, and exploitation experiments. A model multi-physical field monitoring module performs monitoring. A hydrate preparation module communicates with the high-pressure vessel. The high-pressure vessel, the effective stress control module, and the fracturing reinforcement exploitation module are all under hypergravity, and the hydrate preparation module and the water bath temperature control module are under normal gravity.