Composite plugging agent for coalbed methane well

Abstract

The invention discloses a composite plugging agent for a coal-bed gas well. The composite plugging agent comprises the following components in parts by weight: 2-5 parts of a rigid granular material, 2-6 parts of an elastic granular material, 1-4 parts of a fiber material, 1-4 parts of a deformation filling material, 3-7 parts of a quick water loss material and 1-3 parts of a delay expansion plugging material. The composite plugging agent is specially used for leakage of the coal-bed gas well. Slurry prepared from the plugging agent can extend into a bridge in a crack of a coal bed, and a thick and firm filter cake can be deposited; therefore, the tip end of the crack can be effectively isolated, so that conduction of fluid column pressure of sludge can be isolated, and transverse extending of the crack can be prevented; the pressure bearing capacity of the coal bed is improved, and leakage of drilling liquid is prevented.

Description

technical field [0001] The invention relates to the technical field of plugging in coalbed gas drilling, in particular to a composite plugging agent for coalbed gas wells. Background technique [0002] At present, in the process of drilling and completing coalbed methane wells in many areas, there are well leakage phenomena. Most of the wells have serious fractured leakage, and some wells even have total leakage, which seriously affects the normal drilling of coalbed methane wells and makes the coalbed methane The drilling cycle is greatly extended and the drilling cost is greatly increased. [0003] Coalbed methane is an unconventional energy source. Due to the rock mechanics characteristics of the coal seam itself, the formation pressure coefficient of the coal seam is low, and faults and fractures are developed, resulting in extremely low pressure bearing capacity of the formation. the main reason. In the plugging application of coalbed methane leakage wells, some wells...

AI Technical Summary

Problems solved by technology

When the circulation is established and the drilling continues, the previously formed false plugging layer is easily damaged by the drilling tool or is taken out of the fracture by the suction of the annular mud, resulting in secondary leakage

[0004] 3. Although the plugging material enters the leaky layer, the formed plugging layer is not dense enough to effectively improve the pressure bearing capacity of the formation, resulting in continuous lost circulation

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