Double-stage double-rotating-speed well drilling device

Abstract

The invention relates to a double-stage double-rotating-speed well drilling device, and belongs to the industrial fields of oil and gas well drilling, geological prospecting, mine drilling, coal-bed gas development and the like. The double-stage double-rotating-speed well drilling device comprises an outer shell 1, a power assembly 2, a universal shaft coupling 3, a central shaft 4, a variable-speed reversing input assembly 6, a variable-speed reversing conversion assembly 8, a variable-speed reversing output assembly and a secondary drill bit and primary drill bit joint. The device is arranged on the lower part of a shaft bottom drilling tool combination, a small-sized guide hole is drilled according to the characteristic of high rock breaking speed of a primary small drill bit, and a part of the stress of rock is released, so that the rock breaking difficulty of a secondary large-sized drill bit is lowered, the overall well drilling speed is increased, and the control of a well deviation direction and stick-slip vibration is facilitated; the double-stage double-rotating-speed well drilling device has important practical significance to increase of the drilling speed of deep wells and super deep wells and prolonging of the service lives of a drill stem and drill bits. Meanwhile, the double-stage double-rotating-speed well drilling device further has the advantages of simple structure, convenience in operation, convenience in installation, safety and reliability.

Description

technical field [0001] The invention relates to a double-stage double-speed drilling device, which belongs to the fields of oil and gas drilling, coal bed gas drilling, geological exploration and mine drilling equipment. Background technique [0002] With the increasing difficulty of oil and gas field development and the rapid development of drilling technology, oil and gas fields have increasing requirements for drilling speed, especially the number of deep wells, ultra-deep wells, complex structure wells (horizontal wells with long horizontal sections, extended reach wells, branch wells, etc.) During the drilling process, with the increase of the drilling depth, not only the pressure of the drilling fluid column on the bottom of the hole is intensified, but also the strength, vertical stress, and horizontal stress of the formation rock itself increase accordingly, and the drillability of the formation rock As a result, the rate of penetration decreases, which not only affe...

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Problems solved by technology

Patent 201210011193.1 mentions a two-stage and two-speed drilling tool. Although this structure realizes the function of two speeds of the two-stage drill bit, it still has the following deficiencies and cannot fully meet the requirements of on-site drilling technology

(1) The second-stage drill bit is connected to the drill string, and the rotation power and torque are provided by the ground, and the rock-breaking speed of the second-stage drill bit has a limited range of speed increase; (2) The two-stage drill bits have the same rotation direction, and the two-stage drill bit cannot shear and break rock (compressive strength of bottom hole rock>shear strength>tensile strength, so shear crushing is more conducive to rock crushing); (3) The cutting speed difference between the two-stage drill bits is large, resulting in an unreasonable distribution of the drill pressure between the two-stage drill bits , it is difficult to give full play to the advantages of high-speed cutting and drilling of the drill bit, and it is easy to cause unbalanced wear of the two-stage drill bit, which affects the overall drilling speed; (4) cannot meet the technological requirements of sliding drilling in the drilling process of complex structure wells; (5) cannot effectively control Well Deviation Azimuth and Stick-slip Vibration of Drill String

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