Hydrate Reservoir Fracturing Simulation for Permeability and Gas Flow
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Solution Overview
Problem
Existing technologies face challenges in enhancing the permeability and productivity of natural gas hydrate reservoirs due to low heat and mass transfer efficiency, formation of secondary hydrate ices blocking gas seepage channels, and increased seabed disaster risks during decompression, limiting commercial exploitation.
Innovation Solution
An experimental device for reservoir reconstruction includes a simulation reaction kettle with a high-pressure sand filling system, fracture-forming loading system, overburden pressure loading system, gas pressurization system, and fracturing system, along with data collection and control systems, enabling simulation of fracture generation and permeability enhancement through fracturing experiments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If depressurization exploitation is used to produce natural gas from hydrates, then gas production is achieved, but secondary hydrate ices form and block gas seepage channels
Solution Approach 1:
The patent introduces a heating device as an intermediary element to counteract the endothermic effect of hydrate decomposition. By providing external heat to the reservoir during depressurization exploitation, the system prevents secondary hydrate formation that would otherwise block gas seepage channels, thus maintaining productivity while managing the harmful thermal effect
Solution Approach 2:
The patent changes the temperature parameter of the reservoir by introducing heating devices. This parameter change counterbalances the temperature drop caused by endothermic decomposition during depressurization, preventing the formation of secondary hydrate ices and maintaining gas flow channels open
2Productivity
If continuous decompression is applied to increase gas production, then more gas can be extracted, but reservoir strength decreases and risk of seabed disasters increases
Solution Approach 1:
The patent implements continuous monitoring of reservoir strength and seabed stability during the decompression process. By maintaining continuous observation and control rather than intermittent checks, the system can detect early signs of instability and adjust decomposition rates to prevent seabed disasters while maximizing gas extraction
Solution Approach 2:
The patent employs feedback control mechanisms where reservoir strength and seabed stability parameters are continuously measured and used to adjust the decompression rate. This closed-loop control ensures that gas production increases while maintaining safety thresholds, preventing catastrophic failures
3Productivity
If in-situ decomposition of hydrates is used, then gas is produced from the reservoir, but heat and mass transfer efficiency is poor due to low permeability
Solution Approach 1:
The patent divides the reservoir into multiple heating zones with independently controlled heating devices. This segmentation allows targeted thermal energy input in specific regions, improving heat transfer efficiency by focusing energy where needed rather than attempting uniform heating of the entire low-permeability reservoir
Solution Approach 2:
The patent introduces thermal energy input as an additional dimension to the exploitation process. By applying heat from external sources rather than relying solely on the inherent thermal conditions of the low-permeability reservoir, the system overcomes the mass transfer limitations imposed by poor permeability
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 device simulates reservoir conditions to enhance permeability, improve gas production efficiency, and evaluate reconstruction effects, providing a basis for safer and more efficient natural gas hydrate reservoir exploitation.
Implementation Method 1
gas is pressurized by the gas pressurization system and then enters the simulation reaction kettle
Implementation Method 2
the generation of fractures with various fracture widths and/or fracture shapes is simulated in the simulation reaction kettle by the fracture-forming loading system
Implementation Method 3
seabed overburden pressure is simulated for the reservoir medium by the overburden pressure loading system
Implementation Method 4
the reservoir medium is compacted by the high-pressure sand filling system
Data Source
AI summary
An experimental device for reconstruction and production increase of natural gas hydrate reservoirs includes a simulation test kettle, and a high-pressure sand filling system, a fracture-forming loading system, an overburden pressure loading system, a gas pressurization system, a fracturing system and a data collection system which are respectively connected with the simulation test kettle. A reservoir medium is arranged in the simulation test kettle, the generation of fractures with various fracture widths and/or fracture shapes is simulated in the simulation reaction kettle by the fracture-forming loading system, the reservoir medium is compacted by the high-pressure sand filling system, seabed overburden pressure is simulated for the reservoir medium by the overburden pressure loading system, gas is pressurized and then enters the simulation test kettle, a fracturing fluid or proppant is injected into the simulation reaction kettle by the fracturing system, and experimental data is collected and obtained.