Reverse Thrust Tool for Drill Bit Stall Prevention
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Solution Overview
Problem
Coiled tubing and slim hole drilling operations often result in drill bit stalling due to excessive downhole forces, which can lead to undesirable rotation and directional issues during directional drilling, and existing solutions either take too long or cause the drill bit to lose contact with the formation.
Innovation Solution
A reverse thrusting tool with an outer housing and piston assembly that shifts in response to pressure differentials between the drilling fluid and the annulus fluid, reducing downhole forces on the drill bit without inducing relative rotation, using a combination of chambers and a biasing mechanism to control the piston's movement and maintain contact with the formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drill string is locked in place to minimize surge elongation, then the drill bit stalling is reduced, but the drilling operation becomes time-consuming and tedious
Solution Approach 1:
The anti-surge tool employs a dynamic piston assembly that automatically adjusts its position based on pressure differentials between the drill string interior and exterior. The piston moves axially in response to pressure changes, creating a variable restriction that dynamically compensates for surge movements without requiring the drill string to be locked in place, thereby maintaining reliability while reducing operational time loss
2Reliability
If existing anti-surge tools are used to combat stalling, then drill bit stalling is reduced, but the drill bit may rotate and lose directional accuracy
Solution Approach 1:
The tool is segmented into distinct functional components: a housing, a piston assembly with internal passageway, and sealing elements. The piston assembly is separately configured to move axially while the housing remains stationary, allowing the anti-surge function to be isolated to the piston's linear movement without inducing rotation of the entire tool or drill bit, thus preserving directional drilling accuracy
3Reliability
If pressure differential is increased to prevent surge, then drill bit stalling is reduced, but the force on the drill bit increases causing stalling
Solution Approach 1:
The piston assembly acts as an intermediary mechanism that indirectly manages surge forces. Instead of directly applying high pressure differential that would increase downhole force on the drill bit, the piston responds to pressure changes by axially moving to adjust the internal passageway opening, thereby modulating fluid flow and surge effects in a controlled manner that prevents both stalling and excessive force transmission to the drill bit
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 tool effectively reduces the likelihood of drill bit stalling by managing downhole forces through controlled pressure differentials, maintaining consistent contact with the formation and preventing undesirable rotation, thus enhancing drilling efficiency and directional accuracy.
Implementation Method 1
The piston assembly is axially shiftable relative to the housing from an extended position to a retracted position in response to an increase in the pressure differential between the inner passageway and the environment outside the housing
Data Source
AI summary
An anti-surge/reverse thrusting tool for reducing the forces on a drill bit used in subterranean well drilling operations along with methods for drilling wells using a drill string employing the tool. The tool utilizes the pressure differential between drilling fluid flowing through the tool and the fluid located in the well bore annulus proximate the tool to reduce the likelihood of drill bit stall. The tool generally comprises an outer housing and a piston assembly that is axially shiftable relative to the housing.