Coal bed gas well pulse radial drilling and double-pulsating hydrofracturing method

Abstract

Disclosed is a coal bed gas well pulse radial drilling and double-pulsating hydrofracturing method and a whole construction scheme. Equipment matched with the method includes a continuous coiled tubing unit, a high pressure pump, a pulsating pump set, a guider, a pulse generator and a porous nozzle. In a coal bed gas well, the pulse generator and the porous nozzle are utilized to generate high-pressure pulse jets to drive a high-pressure hose to quickly drill into a coal bed to form a radial hole of certain length; a ball is cast into a coiled tubing for maintaining pressure, and a pin is cut off to separate the porous nozzle; the high pressure pump and the pulsating pump set are utilized to pump fracturing fluid in at the same time from the coiled tubing and an oil jacket annulus, the pulse generator generates high-frequency low-amplitude pressure fluctuation, the pulsating pump set generates low-frequency high-amplitude pressure fluctuation, double-pulsating fracturing construction with low-frequency hammering and high-frequency oscillating effects is formed to impact and damage the coal bed, size fracturing is realized finally, and the objectives of substantially improving permeability of the coal bed and increasing yield of a single coal bed gas well are achieved.

Description

technical field [0001] The invention relates to the field of petroleum and natural gas exploitation, and relates to a coalbed gas well stimulation method, in particular to a coalbed gas well pulse radial drilling and double pulse hydraulic fracturing method. Background technique [0002] Coalbed methane is a combustible gas associated with coal, with methane as the main component, and it is a clean energy with great potential. my country's coalbed methane resources are extremely rich, with more than 36 trillion cubic meters of coalbed methane resources below 2,000 meters underground, accounting for more than 10% of the world's total coalbed methane resources, ranking third in the world, second only to Russia and Canada. Effective development of coalbed methane and other unconventional oil and gas resources will help reduce my country's dependence on foreign oil and gas, and ease and improve the structure of energy production and consumption. [0003] In recent years, the pr...

AI Technical Summary

Problems solved by technology

[0004] Radial well technology is a new technology for reservoir stimulation derived on the basis of ultra-short radius horizontal well technology. A number of technical measures for small-sized boreholes. This technology can increase the range of influence of the wellbore, reduce the seepage resistance in the near-wellbore area, and achieve the effect of horizontal wells to a certain extent. However, this technology cannot perform staged fracturing, and the range of pressure relief small limitations

[0005] Coal seam pulsating hydraulic fracturing technology is a new technology proposed in recent years to enhance the effect of coal seam gas drainage. This technology uses the pulsating energy of the liquid to repeatedly hammer the coal seam, causing fatigue damage and shear failure of the coal rock. However, the pulse energy of the fracturing fluid attenuates severely in coal seams with well-developed natural fractures and joints, and the range of action is limited, which seriously limits its field application.

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