Wireline Tool Retrieval via Segmented Joints and Helical Standoffs
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Solution Overview
Problem
Differential sticking phenomena cause downhole tools to adhere to the borehole wall, requiring large axial forces for retrieval, which can exceed the capacity of wireline cables, necessitating costly and time-consuming fishing operations.
Innovation Solution
The implementation of a segmented tool body with compliant or protractible joints that allow axial and rotational displacement, and the use of standoff rings with helical grooves that rotate upon axial motion, to reduce the surface area and increase shear stress at the tool/mud cake interface, facilitating easier retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid tool body is used, then structural strength is improved, but retrieval difficulty increases due to differential sticking
Solution Approach 1:
The tool body is divided into multiple rigid segments connected by compliant joints, allowing each segment to independently manage sticking forces while maintaining overall structural integrity. The segmentation enables localized deformation at joints to reduce differential sticking without compromising the strength of individual tool body sections.
Solution Approach 2:
Compliant joints are introduced between rigid tool body segments, enabling dynamic adjustment of the tool configuration under axial loads. The joints can deform elastically to allow relative movement between segments, reducing the overall axial force required for retrieval while maintaining the rigidity of individual segments during normal operation.
2Ease of operation
If axial force is increased to dislodge the tool, then retrieval capability is improved, but wireline cable failure risk increases
Solution Approach 1:
The compliant joints dynamically adjust the tool's mechanical properties under axial load, transitioning from a rigid structure during normal operation to a more flexible configuration during retrieval. This dynamic behavior distributes stresses and reduces peak axial forces on the wireline cable, preventing cable failure while enabling successful tool dislodgement.
Solution Approach 2:
The tool's effective stiffness parameter changes based on operational conditions. During normal operation, the rigid segments provide high stiffness for structural integrity. During retrieval, the compliant joints deform, increasing the tool's overall compliance and reducing the axial force transmission to the wireline cable, thereby preventing cable failure.
3Ease of operation
If compliant joints are added to reduce sticking, then retrieval ease is improved, but device complexity increases
Solution Approach 1:
The tool body is segmented into multiple sections with compliant joints between them. This segmentation allows the complex retrieval function to be distributed across multiple simple joint elements rather than requiring a single complex mechanism. Each joint is a simple compliant element that independently contributes to reducing sticking forces.
Solution Approach 2:
The compliant joints provide dynamic compliance without requiring complex active control systems. The joints automatically deform under axial load to allow relative segment movement, eliminating the need for motors, sensors, or control algorithms. This passive dynamic behavior reduces device complexity while maintaining retrieval ease.
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
These designs reduce the axial force required to retrieve stuck tools by increasing shear stress in the mud cake, allowing for effective release and retrieval without exceeding wireline cable limits, thus minimizing the need for costly fishing operations.
Implementation Method 1
The joint is configured to extend axially (causing a relative axial displacement of the adjacent tool body sections) when the wireline tool is subject to an axial load
Implementation Method 2
The joint may be further configured to cause a relative rotation between the adjacent tool body sections when the wireline tool is subject to axial load
Implementation Method 3
The standoff rings engage helical grooves in the outer surface of the tool body such that axial displacement of the tool body with respect to the standoff rings causes the rings to rotate
Data Source
AI summary
A first wireline tool embodiment includes a segmented tool body having a joint deployed between each adjacent pair of tool body sections. The joint may be configured to extend axially (causing a relative axial displacement of the adjacent tool body sections) when the wireline tool is subject to an axial load. The joint may include, for example, a compliant joint or a protractible joint. The joint may be further configured to cause a relative rotation between the adjacent tool body sections when the wireline tool is subject to axial load. A second wireline tool embodiment includes a plurality of standoff rings deployed about an outer surface of a rigid tool body. The standoff rings engage helical grooves in the outer surface of the tool body such that axial displacement of the tool body causes the standoff rings to rotate.