Variable Build Motor Pad Extension Mechanism
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Solution Overview
Problem
Directional drilling requires frequent changes in downhole tool bend angles to manage build rates, leading to increased loads, pipe fatigue, and costly operations due to the need for replacing tools with different bend angles.
Innovation Solution
A downhole tool with a movable pad system, controlled by an electric motor and circuitry, allows for adjustable build rates by extending or retracting a pad to engage with the wellbore, enabling changes in build rate without removing the tool from the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a downhole tool with a fixed bend angle is used, then the build rate can be maintained at a specific level, but changing the build rate requires pulling the tool and replacing it with one having a different bend angle, which increases operational time and cost
Solution Approach 1:
The patent applies the dynamics principle by making the pad position adjustable during drilling operations. The pad can be moved radially outward or inward relative to the drill bit, allowing the build rate to be changed dynamically without retrieving the tool. This transforms a static bend angle tool into a dynamic system that can adapt its geometry on-demand, resolving the contradiction between adaptability and operational time loss.
Solution Approach 2:
The patent implements parameter changes by modifying the effective bend angle through pad position adjustment. By changing the radial position of the pad (a geometric parameter), the tool's build rate characteristic is altered without physical replacement. This allows continuous adjustment of the build rate parameter during drilling, eliminating the need to pull and replace tools for different build rate requirements.
2Productivity
If a larger bend angle is used to increase build rate, then directional control is improved, but lateral loads on the drill string increase causing pipe fatigue
Solution Approach 1:
The dynamics principle allows the pad position to be adjusted in real-time based on drilling conditions. When approaching limits where excessive lateral loads would occur, the pad can be repositioned to reduce the effective bend angle, thereby maintaining productivity while protecting the drill string from fatigue damage.
Solution Approach 2:
By dynamically changing the pad position parameter, the system can optimize the bend angle to achieve the desired build rate while staying within safe lateral load limits. This parameter adjustment capability enables the drill string to operate within its strength constraints while maintaining high productivity.
3Ease of operation
If the pad is extended outward to increase build rate, then directional drilling capability is improved, but lateral forces on the drill string increase
Solution Approach 1:
The dynamic adjustment of pad position enables operators to optimize directional control by extending the pad outward when enhanced build rate is needed, and retracting it when lateral forces become excessive. This real-time control provides flexibility in managing the trade-off between ease of directional operation and the forces imposed on the drill string.
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 dynamic adjustment of build rates during drilling, reducing operational delays, costs, and risks associated with tool replacement, while managing lateral forces and curvature changes effectively.
Implementation Method 1
an electric motor, configured to cause extension of the piston
Implementation Method 2
extension of the piston urges the pad outward through the opening of the outer housing
Data Source
AI summary
A variable build motor downhole tool allows changing the build rate in a directional drilling operation without pulling the drill string from the hole and replacing a fixed build sub in the drill string. A pad can be extended upon command to increase the build rate and retracted upon command to decrease the build rate. The pad is mounted on an insert disposed within an outer housing and extends outwardly through the outer housing by action of one or more pistons. Electronics housed in the variable build motor tool are used to receive commands from uphole and cause the pistons to extend, forcing the pad outward to increase the build rate.