Auxiliary rock-carrying tool for gas-inflated underbalanced drilling of branch wells in coalbed methane production

Abstract

The invention discloses an auxiliary cutting carrying tool for coal seam gas extraction gas-filled underbalanced drilling of multilateral wells, and belongs to the field of petroleum, natural gas and geologic drilling. The cutting carrying tool comprises an integrally formed body, a shoulder, a transition diversion slope surface, a middle neck, an inlet diversion slope surface, a spiral migration structure, an outlet diversion slope surface and a joint, wherein the spiral migration structure is arranged at the middle neck. Spiral turbulent strong cyclone flow can be generated by the aid of the spiral migration structure, kinetic energy of liquid-based circulating medium cyclone flow is enhanced in a coal seam gas extraction multilateral well section annulus, and the cutting carrying capacity of the coal seam gas extraction multilateral well section annulus is improved. Rock fragment pellets moving upward in the annulus can be crushed into small rock fragment particles by the aid of an arc-shaped spiral prism, erosive wear of the surface of a drill rod caused by large-particle rock fragments is decreased, the service life of the drill rod is prolonged, the migration performance of the rock fragments in the annulus can be improved by the aid of an arc-shaped spiral groove, and damage to a coal reservoir is reduced.

Description

technical field [0001] The invention relates to the fields of petroleum, natural gas and geological drilling, in particular to an auxiliary rock-carrying tool used for gas-filled underbalanced drilling of branch wells in coalbed gas exploitation. Background technique [0002] Coalbed methane is also called "gas". Its main component is methane, and its calorific value is equivalent to that of natural gas. fuel for life. [0003] Gas underbalanced drilling technology is currently one of the most commonly used measures to reduce coal reservoir damage and protect coal reservoirs in coalbed methane drilling. Combining with multi-branch horizontal well drilling technology can effectively improve the recovery of coalbed methane in low permeability reservoirs Rate. [0004] In the process of realizing the present invention, the inventor finds that there are at least the following problems in the prior art: [0005] 1. Coal reservoir damage is one of the decisive factors affecting...

AI Technical Summary

Problems solved by technology

When drilling coalbed methane with water-based drilling fluid technology, it is usually used to increase the density of drilling fluid to ensure safe drilling, but it is easy to cause coal seam pollution and damage

[0006] 2. In the operation of gas-filled underbalanced drilling branch wells, due to the gravity of the cuttings themselves, the cuttings in the annulus corresponding to the drill pipe body are suspended in the drilling fluid unevenly and have a tendency to settle, resulting in rock carrying in the annulus The ability is poor, which seriously affects the timeliness and cost of coalbed methane drilling

At present, many new tools and instruments are involved in the drilling process of gas-filled underbalanced lateral wells in foreign countries, such as electromagnetic measuring devices for connecting two wells, small-sized geosteering tools, and high-efficiency drag-reducing sub-joints, etc. However, for Cuttings are suspended in the drilling fluid, resulting in poor rock-carrying capacity in the annulus. At this stage, there is no good solution, especially in the operation of aerated underbalanced drilling branch wells, to effectively remove the rock-carrying ability of cuttings in the annulus The tool is still blank and no product has come out

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