Elastomer-Molded Downhole Tractor Wheel for Casing-Safe Traction
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Solution Overview
Problem
Existing downhole propulsion machines, or tractors, face challenges in providing sufficient traction and minimizing damage to wellbore casings while conveying equipment, as they often rely on metal-to-metal contact which can cause significant wear and tear.
Innovation Solution
The use of polymeric material for the tread of the wheels, which engage the wellbore walls, offering increased traction and reduced damage by utilizing polymeric material-to-metal contact, with features like teeth and specific material properties to enhance bonding and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal-to-metal contact is used for wheel traction, then structural strength is improved, but wear and damage to wellbore casing increases
Solution Approach 1:
The patent introduces a polymeric material as an intermediary between the wheel and the wellbore casing. This polymeric tread layer absorbs the mechanical contact, providing both the necessary structural strength for traction and a protective interface that minimizes wear and damage to the metal casing walls.
Solution Approach 2:
The wheel is constructed as a composite structure combining a strong substrate (providing structural strength) with a polymeric tread material (providing protective contact). This composite design allows the wheel to maintain the strength needed for propulsion while the polymeric surface reduces damage to the wellbore casing.
2Object-affected harmful factors
If polymeric material is used for wheel tread, then wear and damage to wellbore casing is reduced, but traction capability may be compromised
Solution Approach 1:
The patent optimizes the polymeric material's physical parameters including hardness, elasticity, and surface texture to achieve the right balance. By carefully controlling these parameters, the polymeric tread provides sufficient friction and grip for effective traction while maintaining the protective function of reducing casing damage.
Solution Approach 2:
The wheel design applies different properties to different parts: the substrate provides structural strength while the polymeric tread provides protective contact. The polymeric material itself has localized variations in hardness and texture to optimize both traction and protection in different contact zones.
3Ease of manufacture
If polymeric material is molded onto substrate, then ease of manufacture and repair is improved, but manufacturing precision may be affected
Solution Approach 1:
The wheel is divided into two separable components: a durable substrate and a replaceable polymeric tread. This segmentation allows the polymeric layer to be molded onto the substrate using efficient molding processes, and enables the tread to be replaced when worn, simplifying manufacturing and repair while maintaining overall wheel precision.
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 polymeric material wheels provide enhanced traction, allowing tractors to overcome obstacles, carry higher payloads, and travel longer distances with minimal damage to the wellbore, reducing wear to less than 0.001%.
Implementation Method 1
The polymeric material wheels provide enhanced traction, allowing tractors to overcome obstacles
Implementation Method 2
Elastomer molded wheel for downhole tractor
Data Source
AI summary
Provided are compositions, methods, and systems that relate to downhole tractor wheels. A downhole tractor system comprising: tubular housing capable of being deployed downhole by wireline; plurality of wheels rotatably mounted to tubular housing, wheels having at least a portion of an outer surface comprising polymeric material. A method for conveying a downhole tool along an inner wall of a wellbore, the method comprising: disposing downhole tool coupled to downhole tractor within wellbore; providing energy to downhole tractor by way of wireline thereby rotating a wheel disposed on downhole tractor; frictionally engaging the inner wall of wellbore with wheel comprising polymeric material disposed on at least a portion of an outer surface of wheel thereby providing a compressive load between the inner wall of the wellbore and polymeric material; allowing downhole tractor to proceed along wellbore wall until downhole tractor reaches desired location; deploying downhole tool for use in wellbore.