Tool and method for injecting cement into top of horizontal well screen pipe without drilling and plugging

Abstract

Provided are a tool and a method for injecting cement into the top of a horizontal well screen pipe without drilling and plugging. The tool for injecting the cement into the top of the horizontal well screen pipe without drilling and plugging is composed of a drilling-free and plugging-free tool, a bumping pressing rubber plug and a fishing tool. During construction, the drilling-free tool is lowered to the well along with a sleeve bunch. A well mouth is pressurized, a packer is sealed through expansion, pressurization is continued, a starting piston is opened, circulation is built, and well cementation is conducted normally. The bumping pressing rubber plug is added for bumping pressing at the later stage of the well cementation, the piston is closed simultaneously, a circulation channel is closed, and the well cementation is finished. After cement curing is finished, fishing is conducted through a small drill pipe connected with a fishing anchor, the small drill pipe and the fishing anchor are lifted after being in place, slips are opened, a fishing drum is blocked, an internal structure of the drilling-free tool is lifted together, and construction is finished. During a working process, a well completion accessory used in the process is not affected by drilling and grinding, service life is greatly prolonged, diameter in a well completion pipe column is large, the inner surface of the well completion pipe column is smooth, and smooth implementation of acid washing and gravel packing is guaranteed. Well completion working time of a single well is reduced by 24 hours on average, and well completion cost is greatly saved.

Description

technical field [0001] The invention relates to a plug-free tool for cementing the top of a horizontal well screen pipe and a method for plug-free operation using the tool. technical background [0002] At present, there are mainly two completion methods for horizontal wells in China: cementing and perforating and screen top cementing completion. Screen top cementing well completion is more and more widely used because of its low cost, low pollution and high yield. More than 60% of newly drilled horizontal wells are completed by screen pipe. The current screen top cementing process is realized as follows: [0003] 1. The composition of pipe string structure: guide shoe + screen pipe + blind plate + outer packer + grading hoop + casing. [0004] 2. After the pipe string is in place, the wellhead is pressurized. First, the outer packer is expanded to seal the screen section and the casing section. Continue to pressurize, open the grading hoop, establish circulation, and ceme...

AI Technical Summary

Problems solved by technology

[0006] However, the current screen top cementing process needs to drill through accessories such as grading hoops and blind plates in the later stage, and there are great hidden dangers:

[0007] 1. The drill plug will cause wear or damage to the grading hoop and the casing, which is easy to cause leakage and may damage the cement sheath at the drill plug;

[0008] 2. The inner wall after drilling the plug is not smooth, and there are burrs, which will scratch pickling and other operation tools, especially rubber tools, which will increase the construction risk; the reduction of the inner diameter after drilling the plug will also affect the production and operation tools.

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