In-situ Methane Explosion Perforation with Molecular Sieve
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Solution Overview
Problem
Current horizontal well staged fracturing technologies for shale gas wells face challenges such as high water consumption, geological hazards, and limited fracture network formation in deep and tight reservoirs, particularly in western China, due to small perforation hole depth and safety concerns with explosive devices.
Innovation Solution
An in-situ methane explosion shaped charge perforating device with a molecular sieve is developed, which internally ignites combustible gases collected by the sieve to achieve deeper perforation and multistage fractures, using a body with check valves, an ignition device, and a concentration sensor connected to an external controller to manage methane collection and ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional explosive fracturing is used, then fracture expansion can be achieved, but safety of initiating explosive devices deteriorates and perforation depth remains limited
Solution Approach 1:
The patent converts the harmful factor of conventional explosives into a beneficial process by using in-situ methane gas accumulation and controlled ignition. Instead of bringing external explosives into the wellbore (which creates safety hazards), the system accumulates methane that is already present in the reservoir and ignites it to create the fracturing effect. This transforms the potential hazard of uncontrolled gas into a controlled energy source for fracture creation.
Solution Approach 2:
The system utilizes the reservoir's own methane resources to power the fracturing process. The molecular sieve accumulates methane that is naturally present in the formation, and this accumulated gas serves as both the energy source and the fracturing medium. The reservoir essentially fractures itself using its own contained energy, eliminating the need for external explosive devices and improving safety while increasing perforation depth.
2Volume of stationary object
If hydraulic fracturing is used, then stimulated reservoir volume increases, but water consumption deteriorates and geological disasters occur
Solution Approach 1:
The patent replaces the hydraulic fracturing mechanism (which uses large volumes of water) with a pneumatic/gas-based mechanism. Instead of injecting water under pressure to create fractures, the system accumulates and ignites methane gas to create controlled explosions that fracture the rock. This substitution of gas for water eliminates the enormous water consumption associated with traditional hydraulic fracturing while still achieving significant stimulated reservoir volume.
Solution Approach 2:
The system changes the fundamental parameter of the fracturing medium from liquid (water) to gas (methane). This parameter change fundamentally alters the process characteristics: gas can be accumulated in controlled quantities using the molecular sieve, ignited to create fracturing energy, and then dissipates without leaving residual water in the formation. This avoids both the water consumption issue and the potential for groundwater pollution.
3Length of moving object
If multi-stage perforation is performed to increase hole depth, then perforation depth improves, but device complexity and operational difficulty deteriorate
Solution Approach 1:
The system enables continuous operation by accumulating methane over time in the molecular sieve, igniting it to create a fracture, and then immediately beginning the accumulation process again in the same or adjacent zones. This continuous cycle of accumulation-ignition-fracturing allows multiple stages to be performed without requiring complex multi-stage equipment or extensive operational coordination, simply by repeating the basic process sequence.
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 enhances the depth of perforation and continuous operation capability, overcoming limitations of conventional explosive fracturing by gathering and igniting in-situ methane for controlled explosions that extend fractures, while maintaining a clean and safe operation environment.
Implementation Method 1
the molecular sieve is configured to gather an in-situ methane in an external stratum into the body
Implementation Method 2
the in-situ methane is ignited and desorbed by the ignition device, then explodes in the body
Data Source
AI summary
An in-situ methane explosion shaped charge perforating device with a molecular sieve is provided and includes a body, an end of the body is fixedly connected to the molecular sieve, two sides of the molecular sieve are fixedly connected to two baffles respectively, each baffle is embedded with several first check valves inside, an end of the body far away from the molecular sieve is fixedly connected to a fixing plate, a center of the fixing plate is embedded with an ignition device, a bottom of the fixing plate is embedded with a concentration sensor, a portion of the fixing plate between the ignition device and the concentration sensor is formed with an air extracting hole, inner walls of a top and a bottom of the body are symmetrically embedded with second check valves, and the ignition device and the concentration sensor are electrically connected to an external controller.