Design method of third-time-drilling well bore structure of narrow pressure window well in deep water

Abstract

The invention discloses a design method of a three-times-drilling well bore structure of a narrow pressure window well in deep water. The design method comprises the following steps that S1, drillingof a surface layer is carried out, specifically, a drill and a hole opener are adopted to drill into the surface layer, after pulling out the drill, a drilling riser string with the wall thickness being 31.75-38.1mm is placed down into the mud surface, and the upper portion of the drilling riser string is connected with a mud mat and then cement slurry is injected for cementing; S2, first-time-drilling is carried out, specifically, the drill is used for drilling in, after pulling out the drill, a first -time-drilling pipe string is placed down, the upper portion of the of the first-time-drilling pipe string is connected with a wellhead, a wellhead seat is hung at the upper portion of the drilling riser string, and the upper portion of the wellhead is connected with an underwater blowout preventer and an upper portion marine riser and then the cement slurry is injected for the cementing; S3, second-time-drilling is carried out, specifically, the drill is used for drilling in, after pulling out the drill, a second-time-drilling pipe is placed down, the first-time-drilling pipe is hung at an upper casing shoe and the cement slurry is injected for the cementing; and S4, third-time-drilling is carried out, specifically, the drill is used for drilling in, the drill is pulled out after drilling to a target layer, and a third-time-drilling casing with the wall thickness being 12.7-20.24 mm is placed down and then the cement slurry is injected for the cementing. The design method of the three-times-drilling well bore structure of the narrow pressure window well in the deep water solves the problem of low safety and unreasonable cost control of a conventional three-times-drilling well bore structure.

Description

technical field [0001] The invention belongs to the technical field of drilling engineering for resources such as oil and natural gas, and specifically relates to a method for designing a three-stage well body structure of a deepwater narrow pressure window well. Background technique [0002] The wellbore structure refers to the layer, depth and corresponding wellbore size that must be lowered into the special casing in the well section above the reservoir. The design methods of the wellbore structure vary with the factors such as the magnitude of the in-situ stress, the direction of the in-situ stress, the magnitude of the collapse pressure, the magnitude of the fracture pressure, the performance of the drilling fluid, and the drilling process. However, if the design of the wellbore structure is unreasonable, it may cause a series of complex situations such as lost circulation, pipe sticking, and even blowout, which will seriously affect the drilling timeliness and drilling...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to avoid the deficiencies in the prior art and provide a design method for deepwater narrow pressure window well three times wellbore structure, to solve the complex situation and drilling problems of conventional three times wellbore structure in deepwater narrow pressure window well The problem of unreasonable cost control

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