Captive Wheel Roller Tool Structure for Wellbore Deployment
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Solution Overview
Problem
Existing roller tools for oil and gas wells have a high risk of components detaching and falling into the wellbore, leading to catastrophic failure and increased costs due to their complex structure and potential for ballistic events.
Innovation Solution
A roller tool design featuring interconnecting tubular portions with annular recesses and a hub that securely holds wheels in place, even if they detach from the bearing assembly, using a combination of annular recesses, seals, and threaded connections to prevent separation and ensure the wheels remain captive, reducing the risk of loss and enhancing operational safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If roller tools use multiple components (wheels, bearings, fixings) to perform their function, then the tool can effectively hold the string away from the wellbore wall and reduce friction, but the risk of components detaching and falling into the wellbore increases significantly
Solution Approach 1:
The invention extracts the wheel retention function from the complex assembly of multiple fixings and bearings, and consolidates it into a simple annular recess structure that passively retains wheels through geometry alone, eliminating the need for additional retention components
Solution Approach 2:
The connector is segmented into functional zones: the annular recess provides passive retention, the threaded portion provides active retention, and the seal provides protection. This segmentation allows each feature to perform its specific function optimally without interfering with others
2Reliability
If roller tools use complex structures with multiple components, then they can provide better wheel retention through multiple fixings, but the device complexity and risk of component failure increase
Solution Approach 1:
The invention merges multiple retention functions (passive geometric retention via annular recess, active threaded retention, and sealing) into a single integrated connector structure, reducing the total number of components while maintaining or improving retention reliability
Solution Approach 2:
The connector serves multiple functions simultaneously: it connects tubular portions, retains wheels through annular recesses, provides threaded retention, and seals the assembly. This multi-functionality eliminates the need for separate components for each function
3Ease of manufacture
If roller tools use fixed components secured by screws and bolts, then the structure can be assembled, but the risk of ballistic events causing component detachment increases
Solution Approach 1:
The annular recess acts as a pre-positioned retention feature that cushions against the harmful effect of ballistic events by providing a geometric constraint that prevents wheel ejection even if other components fail during high-stress events
Data Source
Figure 1~4
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Figure 6~9
AI summary
A roller tool (1) that can be connected into a string for deployment into an oil or gas well includes at least two rollers or wheels (10) located on each side of the roller tool (1), with axes of rotation that are perpendicular to the axis of the roller tool (1). The roller tool further includes at least two interconnecting tubular portions, where one tubular portion (41) comprises a mandrel (45) that connects to another tubular portion (42). An annular hub (20) is fitted over the mandrel (45) and the rollers (10) are connected onto the hub (20). The tubular portions (41, 42) comprise circumferential sleeve sections (56a, 56b) that partially extend over the rollers (10) and resist detachment of the rollers (10) from the roller tool (1). The roller tool (1) can aid passage of a string through a well by holding the string away from the walls of the well and reducing frictional contact.