A method and construction method for cementing plugs in horizontal wells

Abstract

The invention relates to a method for injecting a cement plug into a horizontal well, and a construction method which are used for petroleum industry. The method for injecting the cement plug into thehorizontal well comprises the steps that the density of cement slurry and isolation liquid are equal, the cement slurry and the isolation liquid which are equal in density are displaced into an oil sleeve annulus from a construction pipe column in a spaced mode, the two send interfaces of a cement slurry and isolation liquid displaced section in the oil sleeve annulus are flush with the two sendinterfaces of a cement slurry and isolation liquid displaced section in the construction pipe column, the bottom of the construction pipe column, the oil sleeve annulus and a bottom hole are filled with the isolation liquid, meanwhile, the upper end interface of the isolation liquid displaced firstly and the upper end interface of the isolation liquid displaced lastly are located in the vertical well section of the horizontal well, at the moment, the construction pipe column is uplifted to the upper part of the upper end interface of the cement slurry, thus the cement slurry in the oil sleeveannulus is fused, after the well is shutdown for waiting on cement setting, the cement slurry located on the horizontal section is a suspended cement plug, and then the isolation liquid is washed out.The method has the advantages that construction is easy, operation is easy, sealing is reliable, the temperature-resistant performance is good, drilling is easy, and the method is not prone to beinglimited by the irregular well wall in a wellbore.

Description

technical field [0001] The invention relates to a method for injecting water plugs in horizontal wells in the petroleum industry, in particular to a method and a construction method for injecting cement plugs in horizontal wells, which can form suspended cement plugs in the horizontal section of the horizontal well. Background technique [0002] The suspended cement plug injection process in the vertical well is to use the light oil pipe to replace a certain amount of cement slurry into the wellbore to design the well section, and then wash out the excess mortar. The cement plug is used for interlayer isolation; it has the characteristics of low cost, long validity period, and easy drilling and removal, and has become one of the commonly used sealing techniques in vertical well operations. However, when injecting suspended cement plugs in horizontal well sections, using the technology of injecting suspended cement plugs in vertical wells will cause the cement slurry to flow ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a method and construction method for cementing plugs in horizontal wells, which solves the technical problem that it is impossible to inject cementing plugs in the wellbore of horizontal well sections or highly inclined well sections, so that the cement plugs can become horizontal well sections or wells. The method of interlayer isolation in highly deviated well sections reduces production costs, improves construction efficiency, and solves technical problems that cannot be solved by tools such as packers and bridge plugs

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