Adaptive Support Mechanism for Traction Robots in Irregular Wellbores
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Solution Overview
Problem
Existing downhole traction robots face challenges in providing effective support and traction due to poor contact with well walls, limited adaptability to wellbore deformations, and complex wheel structures that increase maintenance and operational costs.
Innovation Solution
A self-adaptive traction robot with a support mechanism that includes multiple support link assemblies, each controlled by an independent hydraulic cylinder and valve, equipped with micro pressure sensors and displacement sensors for real-time feedback, allowing for precise control of the support mechanism to adapt to irregular wellbore surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If driving wheels are used to support the well wall/pipe wall, then the robot can provide traction force, but the contact effect is poor and slippage occurs easily
Solution Approach 1:
The driving wheel is segmented into multiple driving blocks that can independently contact the well wall. Each driving block can be adjusted radially to ensure reliable contact, transforming a single-point contact into multiple distributed contact points, thereby improving overall contact effect and reducing slippage.
Solution Approach 2:
The driving blocks are made radially adjustable rather than fixed, allowing them to dynamically adapt to the well wall surface. This dynamic adjustment capability ensures continuous reliable contact even when the wellbore geometry changes, resolving the contradiction between maintaining traction force and ensuring contact reliability.
2Device complexity
If driving wheels are distributed on two sides in the same plane, then the robot structure is simplified, but the robot is easy to overturn in circumferential direction
Solution Approach 1:
The driving blocks are positioned at different radial locations rather than all in the same plane. This creates local quality differences in the contact distribution, with blocks at varying radii providing stabilizing moments that prevent circumferential overturning while maintaining structural simplicity.
3Ease of operation
If support link assembly is uniformly opened and closed, then the mechanism is simple to control, but it cannot adapt well to deformation of the wellbore
Solution Approach 1:
The support link assembly is divided into multiple independently controllable segments or groups. Each segment can be opened or closed independently based on local wellbore conditions, allowing the mechanism to adapt to deformations while maintaining relatively simple control through modular operation.
4Force
If driving wheels have complex structure and precise dimensions, then the traction function is effective, but processing, assembly and maintenance become difficult
Solution Approach 1:
The driving blocks are designed as simpler, more robust components that can be easily manufactured and replaced. Rather than complex precision wheels, the modular driving blocks use simpler geometries with radial adjustment mechanisms, making them easier to process, assemble, and maintain while still providing effective traction function.
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
The solution enables the robot to maintain stability and achieve maximum pipe string supporting effect even in complex wellbores, with improved traction force and reduced operational costs due to simplified maintenance and reduced labor costs.
Implementation Method 1
each controlled by an independent hydraulic cylinder and valve
Implementation Method 2
equipped with micro pressure sensors and displacement sensors for real-time feedback
Implementation Method 3
equipped with micro pressure sensors and displacement sensors for real-time feedback
Implementation Method 4
the required friction force cannot be achieved
Data Source
AI summary
The present invention discloses a support mechanism of a self-adaptive traction robot for a complex wellbore and a control method thereof, and relates to the technical field of oil and gas field development. Each support link assembly in a support mechanism is controlled by an independent hydraulic cylinder and hydraulic valve. When a well wall that each support link assembly contacts in a circumferential direction is irregular, the support mechanism contact effect is not ideal, which leads to a decrease in traction force. In this case, a displacement sensor in a telescopic mechanism detects that a displacement of a traction cylinder piston is small, which is fed back to a ground control system, and then a fluid inflow size of support cylinders corresponding to different support link assemblies is adjusted until the displacement sensor in the telescopic mechanism detects an effective traction distance.