Multi-pulse combined fracturing device for perforation of coalbed methane reservoir

Abstract

The invention relates to a multi-pulse combined fracturing device for perforation of coalbed methane reservoir, comprising a percussion initiator; the lower part of the percussion initiator is connected with a perforating barrel; the perforating barrel is internally provided with a frame type ammunition rack, and perforating bullets are loaded on the frame type ammunition rack; the perforating bullets are isolated from low-explosive-velocity liquid explosive by means of capsules, so that the low-explosive-velocity liquid explosive can be safely detonated; the lower part of the composite perforator is connected with a detonation convertor, the lower part of the detonation convertor is connected with a first-stage propulsion device, a central aluminum pipe is positioned in the center of thefirst-stage propulsion device, the lower part of the central aluminum pipe is connected with a delay ignition device, and the lower part of the delay ignition device is connected with a second-stage propulsion device; when the temperature of the outer wall of the central aluminum pipe reaches the ignition point of a propellant, a great deal of high-temperature and high-pressure gas produced by thepropellant acts on the coalbeds in a pulse loading way, thus enabling cracks to rapidly extend; the lower part of the second-stage propulsion device is connected with a connecting rod, a detonating cord is arranged in the connecting rod, the lower part of the connecting rod is connected with a perforator, and the perforator is connected with a pressure measurement tail plug, so that the deflagration pressure change of gunpowder in a fracturing process is reflected; the multi-pulse combined fracturing device has the advantages of treating the multiple coalbeds at a time, and being high in energy utilization rate and cost-saving.

Description

technical field [0001] The invention relates to the technical field of low-permeability coalbed methane development, in particular to a coalbed methane layer perforation multi-pulse combined fracturing device. Background technique [0002] The complexity of geological characteristics of low-permeability coal seams in my country and the fact that coal bed methane mainly occurs in the adsorbed state are the main difficulties in the development of coal bed methane. Firstly, the CBM is desorbed from the coal rock, then diffuses through the matrix and micropores of the coal rock, and finally seeps in the cleats and fractures to reach the bottom of the well. Its unique mining method is drainage-depressurization-desorption-seepage. Although hydraulic fracturing is still the main technology for coalbed methane development and reservoir transformation; the main problem of hydraulic fracturing is that it requires large displacement and low sand ratio construction. As a result, the fr...

AI Technical Summary

Problems solved by technology

At present, the coalbed methane multi-pulse fracturing technology has been further tested and applied. Although preliminary results have been obtained, the energy utilization rate of conventional high-energy gas fracturing devices is not high. If the amount is too much, it is easy to cause collapse and compaction in the area near the well. At the same time, the existing device can only transform one layer at a time, and cannot realize multi-layer transformation at one time. The goal of stable production

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