Bias guiding mechanism of static pointing type rotary steering well drilling tool and control method

Abstract

The invention discloses a bias guiding mechanism of a static pointing type rotary steering well drilling tool and a control method, and belongs to the technical field of petroleum and natural gas welldrilling. The bias guiding mechanism of the static pointing type rotary steering well drilling tool comprises a drill bit connecting shaft and a non-rotary outer cylinder, and further comprises a flexible hose, bias mechanisms and a sliding block connecting piece; the flexible hose is connected with the drill bit connecting shaft, and the bias mechanisms are installed in the non-rotary outer cylinder; the bias mechanisms comprise center adjusting sliding blocks, spiral telescopic mechanisms and control motors; the sliding block connecting piece is arranged on the outer part of the drill bit connecting shaft in a sleeving mode; and the center adjusting sliding blocks are connected with the control motors through the spiral telescopic mechanisms and are installed in the sliding block connecting piece, the center adjusting sliding blocks are driven by the control motors to move forward and backward to push the drill bit connecting shaft, and control over structure bend angles and tool face angles is realized. The disturbance and the load applied on the motors are both small and stable in the process of making a connection, the electric energy requirement of a system is reduced obviously, and the service life of the guiding tool is prolonged; and the scheme is simple and easy to operate, and the structure is compact.

Description

technical field [0001] The invention belongs to the technical field of oil and gas drilling, and in particular relates to an offset guiding mechanism and a control method of a static pointing rotary steering drilling tool. Background technique [0002] Rotary steerable drilling tools represent the highest level of development of petroleum directional drilling tools. Rotary steerable drilling tools can be divided into pushing type and pointing type according to the action mode of the steering mechanism, and can be divided into dynamic type and static type according to whether the outer cylinder of the steering tool rotates. The push-on type refers to the interaction between the steering mechanism and the well wall, and the direction of the drill bit is controlled by the generated reaction force. This method will produce a spiral wellbore, and its steering ability is limited by the formation structure, and its steering ability in soft formations is poor; The type means that t...

AI Technical Summary

Problems solved by technology

Its shortcomings are as follows: ①The guiding function of this case is realized by the flexible mandrel, which needs to withstand high-intensity alternating stress, which is prone to fatigue damage; ②The double eccentric ring bias mechanism of this case is driven by harmonics Driven by the mechanism, the flexible parts in the harmonic drive mechanism will be periodically deformed and easily damaged by fatigue; ③The braking effect of this case is realized by the electromagnetic clutch corresponding to the inner ring and the outer ring, because an additional design is required to match the bias mechanism braking device, increasing the complexity of the system

Its shortcomings are: ① Motor vector control is a method of dynamically adjusting the direction of the drill bit. This method is relatively complicated, and the control effect will be affected by the disturbance caused by the drill bit during the drilling process; The method for the braking device to lock the position of the eccentric ring will increase the complexity of the system, and the case does not elaborate on the structure of the braking device

Its shortcoming is that the guiding control of the solenoid valve belongs to the method of dynamically adjusting the direction of the drill bit, and the guiding effect will be affected by the interference brought by the drill bit, so it is difficult to realize precise guiding control

The disadvantage is that the hydraulic pump in this system is powered by drilling fluid, and the fluctuation of drilling fluid pressure will affect the steering effect, which increases the difficulty of precise hydraulic steering control

The disadvantage is that the hydraulic control system is easily affected by the pressure of the drilling fluid, and multiple components are in contact with the drilling fluid, the service life will be affected, and the sealing requirements for the drilling fluid are high

[0010] At present, the existing technology has the following defects that need to be solved urgently: ①The motor control method based on the double eccentric ring structure and the servo valve control method based on the hydraulic system are both dynamic guidance methods, and the control method is relatively complicated and will be disturbed by the drill bit ②The braking function of the bias mechanism is realized by additional braking devices, such as the clutch of the double eccentric ring, the brake of the motor, and the self-locking mechanism of the gear transmission, which increase the complexity of the system; ③ When the offset steering mechanism based on double eccentric rings is driven by a harmonic drive mechanism, the flexible parts in the harmonic drive mechanism are prone to fatigue damage; ④ The design of the offset steering mechanism based on hydraulic control needs to consider the sealing of the drilling fluid, and Drilling Fluid Pressure Fluctuation Affects Steering Control

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