Supercritical co2 jet cavity creation and multi-stage synchronous deflagration fracturing method for coalbed methane horizontal wells

Abstract

The invention relates to a coalbed methane horizontal well supercritical CO2 jet flow cavity construction and multi-segment synchronous deflagration fracturing method. The method comprises the following steps: completing coalbed methane horizontal well drilling, introducing a coiled tubing into an supercritical CO2 rotary jet flow rock-breaking device to the bottommost end of a shaft, and performing pore broadening on the shaft by using an underground supercritical CO2 rotary jet flow rock-breaking device in order to form a cylindrical pore which is 1.0-1.5 meters in diameter and is 2-4 meters in length underground; after first-segment pore broadening is finished, lifting a rotary jet-flow tool to perform second-segment pore broadening work and so forth to finish pore broadening work of all well segments, wherein the segment distances are 80-100 meters; putting a solid explosive into a pore broadening cavity by using the coiled tubing after finishing pore broadening, and introducing a screen pipe; lastly, pressurizing by using a ground high-pressure CO2 pump to ignite the explosive, and mixing generated high-energy gas with a supercritical CO2 fracturing coalbed. By adopting the method, a plurality of complex volume cracks can be generated in the coalbed, explosive fracturing contributes to coalbed stress unloading after pore broadening, and the coal rock permeability can be improved effectively, so that the yield of a coalbed methane horizontal well is improved.

Description

technical field [0001] The invention relates to a coalbed gas well fracturing stimulation method, in particular to a coalbed gas horizontal well staged fracturing method, which belongs to the field of petroleum drilling. Background technique [0002] Hydraulic fracturing technology is currently the main application technology for coalbed methane stimulation. The commonly used fracturing fluid media are water-based fracturing fluid, gas energized (foam fracturing fluid) and alcohol-based fracturing fluid. The hydraulic fracturing technology is well developed and the process is relatively mature, but there are limitations in that the construction period is long, drainage is required, the equipment is complicated, the cost is high, and the coal seam is often polluted, and most of the cracks produced are single main cracks, and it is difficult to form a network of cracks. High-energy gas fracturing has also been applied in the development of coalbed methane. Explosion shock wave...

AI Technical Summary

Problems solved by technology

The hydraulic fracturing technology is well developed and the process is relatively mature, but there are limitations in that the construction period is long, drainage is required, the equipment is complicated, the cost is high, and the coal seam is often polluted, and most of the cracks produced are single main cracks, and it is difficult to form a network of cracks

High-energy gas fracturing is also applied in the development of coalbed methane. Explosion shock waves can create more micro-fractures in the formation, but there are limitations such as low energy and short fractures.

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