Extendable Cutting Tool for Wellbore Enlargement
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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 are limited in their ability to efficiently enlarge the borehole and manage arm extension mechanisms.
Innovation Solution
An extendable cutting tool with a tubular body, pivotally connected arms, and a fluid-pressure operated piston system that can be locked and extended via a controller, allowing for precise arm deployment and retraction using sensors and actuators to manage arm position and extension.
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 borehole). This dynamic transformation allows the same tool to serve multiple functions: drilling through casing with arms retracted, then enlarging the hole with arms extended, thereby accommodating larger casing strings and increasing production flow area
Solution Approach 2:
The underreamer arms are nested within the drill string assembly during the drilling operation, allowing the tool to pass through existing casing. After passing through the casing, the arms are deployed outward to enlarge the borehole, creating a larger annulus for subsequent larger casing installation
2Area of moving object
If underreamers with extendable arms are used to enlarge the borehole, then the production flow area increases, but the complexity of the arm extension mechanism increases
Solution Approach 1:
A hydraulic piston system is employed to actuate the underreamer arms between retracted and extended positions. The piston is controlled by a check valve that can be operated from the surface, allowing remote control of the complex extension mechanism without requiring downhole intervention. This hydraulic system provides smooth, controlled movement of the arms while managing the complexity through centralized control
Solution Approach 2:
Sensors are integrated into the arm mechanism to detect the position (retracted or extended) and provide feedback to a controller. This feedback system ensures the arms are in the correct position before and during drilling operations, and automatically triggers the extension/retraction sequence, reducing the need for complex manual control mechanisms
3Device complexity
If the arm extension mechanism is simplified, then the device complexity reduces, but the precision of arm position control decreases
Solution Approach 1:
Position sensors mounted on the underreamer arms detect whether the arms are in the retracted or extended position and provide this information to a controller. The controller uses this feedback to determine when to activate the hydraulic piston for extension or retraction, ensuring precise positioning control through a relatively simple hydraulic mechanism
Solution Approach 2:
Complex mechanical position control mechanisms are replaced with an electronic control system that uses sensors to detect arm position and a controller to manage the hydraulic piston actuation. This substitution of electronic control for mechanical control achieves precise positioning while maintaining simplicity in the physical extension mechanism
4Area of stationary object
If the underreamer arms are extended to enlarge the borehole, then the annulus for cementing increases, but the time required for arm extension and retraction increases
Solution Approach 1:
The hydraulic piston system provides rapid extension and retraction of the underreamer arms compared to mechanical screw or linkage mechanisms. The hydraulic fluid can be quickly pressurized and directed to the piston, enabling fast arm deployment and retraction, thereby minimizing the time loss during transitions between drilling and reaming operations
Solution Approach 2:
The underreamer arms are pre-positioned in the retracted state during the drilling operation, allowing the drill bit to pass through the casing shoe without interference. Once the bit has cleared the casing, the arms are then extended in a single rapid motion to begin reaming, eliminating the need for gradual extension and reducing the time required for the transition
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 enlargement of the wellbore diameter, increasing the production flow area and reducing equivalent circulation density, while allowing for precise control of arm extension and retraction to accommodate various geological formations.
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
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
Embodiments of the present invention generally relate to extendable cutting tools for use in a wellbore. In one embodiment, 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 tool further includes the first piston. 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.