Downhole Tractor Fluid Valve Impulse Propulsion
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Solution Overview
Problem
In deep and tortuous wells, traditional downhole tractor devices face challenges in pushing drillstrings and tubulars due to excessive friction, especially in open or unlined holes where formation strength is inadequate, and existing solutions rely on contact with the borehole wall or drilling motors, which are inefficient.
Innovation Solution
A method and apparatus utilizing a fluid-transmitting member with a valve that generates impulses by varying fluid flow, creating pressure surges to urge the member forward, allowing for advancement without relying on axial fluid flow direction, and a downhole tractor comprising a fluid-transmitting member with a valve that opens and closes at selected rates to produce impulses for directional movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional downhole tractor devices use gripper mechanisms to engage the borehole wall, then they can push drill strings in cased holes, but they fail in open or unlined holes due to inadequate formation strength
Solution Approach 1:
The patent replaces the mechanical gripper system that relies on formation strength with a fluid-based propulsion system. Fluid is pumped through the drill string and directed against the bottom hole assembly to create thrust, eliminating the need for mechanical engagement with the borehole wall and making the system reliable in both cased and open hole conditions.
Solution Approach 2:
The invention uses hydraulic propulsion by pumping fluid through the drill string and directing it against the bottom hole assembly. The fluid pressure creates thrust forces that push the drill string forward, providing reliable operation in open holes where mechanical grippers would fail due to inadequate formation strength.
2Force
If downhole tractors rely on contact with casing or borehole wall, then they can pull tubing string, but they experience excessive friction in high inclination or tortuous wells
Solution Approach 1:
The patent replaces contact-based mechanical traction with fluid-based propulsion. Instead of relying on friction between grippers and the borehole wall to pull the tubing string, the system pumps fluid through the drill string to generate thrust that pushes the assembly forward, significantly reducing friction losses in high inclination and tortuous wells.
Solution Approach 2:
The invention extracts the propulsion function from the mechanical contact system and implements it through fluid pressure. By taking out the reliance on borehole wall contact, the system eliminates the associated friction problems while maintaining the ability to move the drill string and tubing assembly.
3Force
If coiled tubing is pushed with additional force from surface, then more force is applied, but the tubing locks in the wellbore due to helical or sinusoidal lockup
Solution Approach 1:
The patent replaces surface-applied mechanical force with downhole fluid-based propulsion. By pumping fluid through the drill string to create thrust at the bottom hole assembly, the system pushes the coiled tubing forward from within, eliminating the lockup problem that occurs when surface force is applied to tubing in helical or sinusoidal configurations.
Solution Approach 2:
The invention introduces fluid pressure as an intermediary to transfer force to the coiled tubing. Instead of directly pushing the tubing from surface where lockup prevents force transfer, the fluid acts as a mediator that generates thrust internally at the bottom hole assembly, efficiently propelling the tubing forward without lockup issues.
4Productivity
If tractor mechanism pushes drill pipe until end of stroke, then drill bit advances, but the device must pull drill bit upward and release to move downward in start/stopped increments
Solution Approach 1:
The patent enables continuous drilling advancement by generating continuous fluid thrust that constantly pushes the bottom hole assembly forward. This eliminates the start-stopped cycling of traditional tractors that must retract and re-engage, allowing the drill bit to advance continuously without interruption and significantly reducing non-productive cycling time.
Solution Approach 2:
The invention uses periodic modulation of fluid flow to the bottom hole assembly to create controlled thrust cycles. By varying the fluid pressure periodically, the system maintains continuous forward motion while allowing for controlled advancement rates, eliminating the complete stop-start operation of traditional tractors and improving overall drilling continuity.
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 advancement of drillstrings and tubulars in challenging well conditions by leveraging fluid momentum and pressure surges, reducing reliance on gravity and borehole contact, and facilitating movement in both drilling and retrieval operations.
Implementation Method 1
leveraging fluid momentum and pressure surges
Implementation Method 2
creating pressure surges to urge the member forward
Data Source
AI summary
A method of translating a member through a bore involving moving fluid through a tubular member such as a drill string, and generating impulses on the member by varying the passage of fluid through the member using a valve which opens at a first rate and closes at a different second rate to urge the member to advance in a selected direction. The valve may close quickly and open slowly, or may close slowly and open quickly.