Wellbore Casing Recovery Using Magnetostrictive Logging and Down Hole Power Tools
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Solution Overview
Problem
During well abandonment, casing recovery is often hindered by solids settling on the casing, requiring higher forces than conventional rigs can provide, leading to partial removal and guesswork in cutting strategies due to the lack of a reliable method to estimate the force needed to dislodge stuck casing sections.
Innovation Solution
A method involving a bottomhole assembly with a casing cutter and spear, combined with a wireline deployable magnetostrictive logging tool to identify the stuck point, allowing for precise cutting above the stuck point and recovery of casing in a single trip, utilizing a BHA with a packer and Down Hole Power Tool for assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional rig pulling is used to remove casing, then the procedure is simple, but the force required exceeds rig capability when solids have settled on the casing
Solution Approach 1:
A Down Hole Power Tool acts as an intermediary device between the rig and the stuck casing. The tool is deployed into the wellbore and directly engages the casing at the stuck location, applying high pulling forces locally without requiring the entire rig system to generate that force. This mediator approach enables force application at the point of need while keeping the rig system relatively simple.
2Reliability
If Down Hole Power Tools are used to apply high forces, then casing can be removed, but the casing must be cut into shorter lengths due to force limitations
Solution Approach 1:
The stuck casing is divided into manageable segments by making cuts at strategically determined locations. The logging tool identifies the stuck point, and cuts are made above this point to create sections that can be removed individually. This segmentation transforms a single difficult recovery operation into multiple simpler operations on smaller casing sections.
Solution Approach 2:
The logging tool is deployed before the power tool to identify the stuck point and determine optimal cut locations. This preliminary information-gathering action enables precise planning of where to cut the casing, ensuring that subsequent power tool application and removal operations are as efficient as possible.
3Productivity
If casing is cut based on guesswork, then operational time is reduced, but cutting location accuracy is poor leading to inefficiency
Solution Approach 1:
The mechanical guesswork approach is replaced with a logging system that uses magnetostrictive effects to precisely locate the stuck point. The logging tool measures physical properties of the casing and annulus to identify where the casing has become stuck, providing accurate depth information that replaces trial-and-error cutting decisions.
Solution Approach 2:
The logging tool provides real-time feedback about the casing condition and stuck point location. This information feeds back into the decision-making process for where to position cuts and how to proceed with recovery, creating a closed-loop system that continuously optimizes the recovery operation based on actual well conditions.
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 recovery of casing in a single trip by accurately determining the stuck point and required force, reducing operational time and minimizing damage, while allowing for efficient clearance of cuttings and debris.
Implementation Method 1
One such method utilises wireline tools that log the pipe using the magnetostrictive effect
Data Source
AI summary
A method of recovering casing from a wellbore in which: a logging tool is run to an estimated stuck point of the casing through the central bore of the casing spear and casing cutter; the casing spear is attached to the casing and tension applied so that logging can be performed over a length at an estimated stuck point both with and without tension to provide the verified stuck point; and the casing cutter is positioned relative to this to cut the free casing; and the spear used to remove it. The method can be performed on a single trip. Embodiments include incorporating a packer to circulate fluid during casing cutting; a disconnect, anchor mechanism and motor to allow use of a motor to operate the cutter; and a Down Hole Power Tool with a method of establishing the required force to recover a length of stuck casing.