Method for directionally drilling inclined hole in steeply-inclined stratum

Abstract

The invention discloses a method for directionally drilling an inclined hole in the steeply-inclined stratum, comprising construction of a straight-hole section, a deflecting section and a hole micro-increasing inclined section as well as comprises the following specific steps of: firstly, drilling by adopting a general directional drilling technology; secondly, feeding an orifice pipe; thirdly, finishing straight hole section construction by adopting a diamond wire line coring drilling technology; fourthly, starting the deflecting section construction by adopting the general directional drilling technology; fifthly, reaming by adopting the general directional drilling technology; and sixthly, constructing the hole micro-increasing inclined section by adopting the diamond wire line coringdrilling technology. The invention has the benefits that the general directional drilling technology and the diamond wire line coring drilling technology are organically combined to successfully solve the problems that a drill rig is difficult to bend, easy to break off and difficult to realize high rotating speed drilling, effectively improve the geological exploration quality, shorten the construction period and reduce the cost.

Description

technical field [0001] The invention relates to a drilling construction method, in particular to a method for directional inclined hole drilling in steeply inclined formations. Background technique [0002] In the long-term core drilling construction, the drilling trajectory will deviate from the design due to the influence of stratum dip angle, lithology soft and hard interbed, fault, WOB and other factors. A large number of construction drilling statistics show that: in steeply inclined strata Medium (formation dip > 45°), most (more than 90%) boreholes deviate in the down-dip direction. Drilling in steeply inclined strata, if it migrates along the dip, it will cause the following adverse consequences: ①The drilling depth will be greatly increased; ②The construction difficulty will increase; ③The geological design purpose will not be achieved; ④The construction cost will increase exponentially, etc. . In order to solve these problems, many boreholes need to design and...

AI Technical Summary

Problems solved by technology

[0005] ① The annulus gap between the drilling tool and the well wall is small (only 2-3mm), and the drilling tool is difficult to bend;

[0006] ② The wall thickness of the drilling tool is relatively thin (the normal thickness is 5mm, and the thread connection is only 1.75mm), and the drilling tool is drilled in the inclined hole after the deflection, which is easy to cause the drilling tool to break;

[0007] ③ After deflection, it is difficult for the drilling tool to go up and down; the friction force increases, and it is difficult to achieve high-speed drilling

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