Downhole Spearing Tool for Single-Trip Casing Removal
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Solution Overview
Problem
Conventional methods for removing well casing are time-consuming and costly due to the need for multiple trips with separate cutting and extraction tools, especially in slot recovery operations where cement and barite settling restrict cutting and pulling.
Innovation Solution
A downhole tool assembly with a cutting device and a hydraulically actuated spearing device that includes a corrugated mandrel and grapple members with wickers, allowing for axial and rotational movement, expansion, and collapse to engage and remove casing segments in a single trip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate cutting and extraction tools are used with multiple trips, then the casing can be cut and removed, but the operation becomes time-consuming and costly
Solution Approach 1:
The patent combines separate cutting and extraction tools into a single integrated downhole assembly that performs both functions. The cutting device includes cutting elements that can sever casing, while the extraction device includes engagement members that can grip and retrieve the cut casing segments, all within one tool string that can be deployed in a single trip.
Solution Approach 2:
The downhole assembly is designed as a universal tool that performs multiple functions: cutting the casing at desired depths and extracting the resulting segments. This multi-functional design eliminates the need for separate specialized tools and multiple operational trips, directly addressing the time loss problem.
2Productivity
If multiple trips are made with separate tools, then cutting and extraction can be performed, but the operation becomes complex and expensive
Solution Approach 1:
The patent merges the cutting device and extraction device into a single integrated assembly. The cutting elements and extraction members are positioned within the same tool string, allowing both cutting and extraction operations to be performed in one coordinated maneuver, thereby reducing operational complexity.
Solution Approach 2:
The cutting device incorporates multiple cutting elements that can be positioned at different axial locations to cut casing at multiple depths simultaneously or sequentially. This segmentation of cutting functions within a single tool allows complex cutting patterns without requiring multiple separate tool deployments.
3Productivity
If cutting is performed in slot recovery operations, then casing can be removed, but cement and barite settling restrict the operation
Solution Approach 1:
The patent employs preliminary action by using the extraction device to engage and retrieve cut casing segments before the harmful effects of cement and barite settling fully develop. The extraction members can grip and pull casing segments upward through the annulus, removing them before cement bridges or barite accumulations prevent further operation.
Solution Approach 2:
The extraction device incorporates dynamic engagement members that can adapt to varying annular conditions. The engagement members can be activated to grip casing segments and pulled upward, creating dynamic movement that disrupts cement and barite settling patterns and prevents formation of blocking accumulations.
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 cutting and removal of multiple casing segments in a single trip, reducing rig time and costs by integrating cutting and extraction functions, and overcoming restrictions from cement and barite settling.
Implementation Method 1
a spring operative with the piston and biasing the grapple toward a collapsed position. Responsive to an increase in hydraulic pressure, the piston compresses the spring and axially moves the grapple, expanding the grapple members. Responsive to a subsequent decrease in hydraulic pressure, the spring decompresses and axially moves the grapple, collapsing the grapple members.
Implementation Method 2
Responsive to an increase in hydraulic pressure, the piston compresses the spring and axially moves the grapple, expanding the grapple members.
Data Source
AI summary
A spearing device for removing casing from wellbore includes a top sub, a bottom sub, and a mandrel coupled to the top and bottom subs. The device includes a grapple having a corrugated inner surface corresponding to a corrugated portion of the mandrel and an outer surface including wickers for engaging an interior surface of the casing. A piston is disposed within the mandrel and operatively coupled to the grapple. A spring operates with the piston and biases the grapple toward a collapsed position. The grapple axially and rotationally moves along the corrugated outer surface of the mandrel. The grapple expands and collapses in response to axial movement relative to the mandrel. The piston compresses the spring and axially moves and expands the grapple in response to increases in hydraulic pressure. In response to subsequent decreases in hydraulic pressure, the spring decompresses and axially moves and collapses the grapple.