Rotary Steerable Drill Bending Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing underground drilling systems face challenges in adjusting the direction and degree of drilling without removing the drill string from the borehole, limiting the ability to switch between straight and directional drilling efficiently and accurately.
Innovation Solution
A rotary steerable drilling apparatus with a bendable member and reduction gear system that allows in-situ adjustment of the tool face angle and degree of bending, enabling directional changes by applying compressive forces to a flexible housing with weakening features, allowing for precise control of drilling direction and angle from the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bent housing or subassembly is used to steer the drill bit in directional drilling, then directional drilling capability is improved, but the ability to return to straight drilling is worsened because the bent housing must be pulled out of the bore hole
Solution Approach 1:
The housing is designed to be bendable rather than fixed, allowing it to dynamically change its configuration. The housing can be bent to a predetermined angle for directional drilling and then straightened to return to straight drilling, eliminating the need to pull the drill string out of the bore hole to switch drilling modes
Solution Approach 2:
The degree of bending of the housing can be adjusted by applying forces through actuators that move between extended and retracted positions. This allows continuous adjustment of the bending parameter to achieve different steering angles and to return to straight drilling configuration
2Ease of operation
If the drill string is rotated to adjust the tool face angle of the bent housing, then the direction of drilling can be changed, but the severity of the dog leg cannot be adjusted without pulling the bent housing out of the bore hole
Solution Approach 1:
The housing bending capability transforms the static bent housing into a dynamic structure where both the tool face angle and the degree of bending can be adjusted in real-time while the drill string remains in the bore hole, enabling independent control of drilling direction and dog leg severity
Solution Approach 2:
Actuators serve as intermediary mechanisms that apply forces to the housing to control its bending degree. These actuators can be extended or retracted to apply compressive or tensile forces, thereby adjusting the housing bend and controlling the dog leg severity without requiring drill string removal
3Adaptability or versatility
If cam surfaces or eccentric stabilizers with an eccentric mass are used to induce an offset in the drill bit, then directional drilling is achieved, but the degree of change in drilling direction cannot be altered without pulling the drill string from the bore hole
Solution Approach 1:
The housing bending mechanism provides dynamic adjustability of the drilling direction degree through actuator control, replacing the static offset mechanism with a dynamically controllable system that can be adjusted in-situ
4Adaptability or versatility
If members radially outward from the drill string are extended to contact the bore hole wall to deflect the drill bit, then directional drilling with adjustable dog leg severity is achieved, but the system becomes complex and requires precise control of the extension mechanism
Solution Approach 1:
The flexible housing acts as a simplified alternative to rigid extension members. The housing can be bent to deflect the drill bit by applying forces through actuators, eliminating the need for complex radial extension mechanisms while maintaining the ability to adjust both drilling direction and dog leg severity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and precise directional control of drilling without removing the drill string, allowing for seamless transitions between straight and directional drilling, and adjusting the degree of change in drilling direction and tool face angle without pulling the drill string from the borehole.
Implementation Method 1
a bendable member adapted to be incorporated into the bottom hole assembly, the bendable member having a preferential direction in which the bendable member bends when a force is applied to the bendable member
Data Source
AI summary
A rotary steering apparatus for a drill string in which a bending section induces a bend in a portion of the bottom hole assembly of the drill string by using the rotation of the drive shaft that drives the drill bit during normal drilling, while operating at a reduced or zero drilling mud flow rate, to drive a reduction gear that rotates a nut or cam so as to place a tension tube into tension. The tension tube abuts a flexible housing and places the flexible housing in compression. The flexible housing has a local weakening formed in it that causes it to preferentially bend in a predetermined direction. Compression in the flexible housing causes the housing to bend, which bends a portion of the bottom hole assembly so as to alter the direction of drilling. Rotation of the drive shaft at reduced or zero mud flow rate also causes the drive shaft to drive rotation of a second reduction gear the output of which rotates the bent portion of the bottom hole assembly thereby altering its tool face angle.