Extendable Wellbore Cutting Tool With Hydraulic Arm Actuation
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Solution Overview
Problem
In wellbore drilling operations, the need for multiple drill bits of different sizes to accommodate progressively smaller casing/liner strings reduces the production flow area, and existing underreamers lack efficient control mechanisms for extending and retracting arms during drilling.
Innovation Solution
A tubular cutting tool with a pivotally connected arm that extends outward in response to fluid pressure, featuring a lock mechanism and a controller for controlled extension and retraction, along with sensors and actuators for precise operation, allowing for the enlargement of the wellbore and efficient drilling with a single drill bit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple drill bits of different sizes are used to accommodate progressively smaller casing/liner strings, then the drilling operation can proceed through multiple casing strings, but the production flow area is reduced
Solution Approach 1:
The underreamer arms are designed to be dynamically extendable from a retracted position (for passing through casing) to an extended position (for enlarging the wellbore). This dynamic transformation allows a single drill bit system to adapt to different operational requirements, eliminating the need for multiple drill bits of different sizes while maintaining larger production flow area
Solution Approach 2:
The underreamer arms are nested within the drill string assembly during the drilling phase, allowing the assembly to pass through the casing. Once through the casing, the arms are deployed outward to create the enlarged wellbore. This nesting approach enables a single versatile tool to perform multiple functions that would otherwise require multiple specialized tools
2Area of stationary object
If underreamers with extended arms are used to enlarge the wellbore, then the production flow area increases, but the control mechanism for extending and retracting arms becomes more complex
Solution Approach 1:
A hydraulic actuating system is employed to control the extension and retraction of the underreamer arms. The hydraulic system provides smooth, controlled movement of the arms between retracted and extended positions, and can be actuated from the surface, simplifying the control mechanism compared to complex mechanical linkage systems while enabling precise control of the arm positioning
Solution Approach 2:
The hydraulic fluid acts as an intermediary between the control system and the underreamer arms. By using hydraulic pressure as the mediating force, the system achieves controlled arm movement without requiring direct mechanical connection or complex control mechanisms, reducing overall system complexity while maintaining precise control capability
3Area of stationary object
If underreamers are used to enlarge the wellbore below casing, then larger casing/liner strings can be installed with increased flow area, but the equivalent circulation density increases
Solution Approach 1:
The dynamic extension of underreamer arms creates a gradual transition zone rather than a sudden enlargement. This gradual enlargement allows drilling fluid to circulate more effectively through the annulus, reducing the equivalent circulation density compared to abrupt wellbore enlargements, while still achieving the goal of installing larger casing strings with increased flow area
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 the enlargement of the wellbore to accommodate larger casing/liner strings, increasing production flow area and reducing equivalent circulation density, while allowing for controlled and efficient extension and retraction of cutting tools during drilling operations.
Implementation Method 1
The first piston is disposed in the body bore, has a bore therethrough, and is operable to move the arm from the retracted position to the extended position in response to fluid pressure in the piston bore exceeding fluid pressure in the opening
Data Source
AI summary
A tool for use in a wellbore includes a tubular body having a bore therethrough, an opening through a wall thereof, and a connector at each longitudinal end thereof; and an arm. The arm is pivotally connected to a first piston and rotationally coupled to the body, is disposed in the opening in a retracted position, and is movable to an extended position where an outer surface of the arm extends outward past an outer surface of the body. The first piston is disposed in the body bore, has a bore therethrough, and is operable to move the arm from the retracted position to the extended position in response to fluid pressure in the piston bore exceeding fluid pressure in the opening. The tool further includes a lock operable to retain the first piston in the retracted position; and a second piston operably coupled to the lock.