Sacrificial Wellbore Plugging Tool for Stuck Downhole Tools
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Solution Overview
Problem
Conventional methods struggle to form a cement plug in a wellbore when a downhole tool is stuck, preventing effective isolation of undesired reservoirs or production zones, especially when a bottom hole assembly is present, as it obstructs cement access and distribution.
Innovation Solution
A sacrificial tool with an overshot fishing tool and a liner hanger is used to engage and establish circulation through the stuck downhole tool, allowing cement to be pumped into the annulus between the tool and the wellbore wall for isolation, with the overshot fishing tool and stuck tool left in place as the cement cures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bridge plug method is used to form a cement plug, then cement isolation of subterranean formations can be achieved, but the method becomes impossible when a downhole tool is stuck in the wellbore
Solution Approach 1:
The invention extracts the stuck downhole tool from the cementing process by running a sacrificial bridge plug over it. The sacrificial tool is set independently of the stuck tool, allowing cement to be placed around the stuck tool without requiring it to be moved or removed. This separates the cementing function from the stuck tool presence.
Solution Approach 2:
The sacrificial bridge plug acts as an intermediary between the cement slurry and the stuck downhole tool. It provides a surface for the cement to bond to and displaces the cement slurry as it sets, enabling proper cement isolation while the stuck tool remains in place. The sacrificial tool mediates the interaction between cement and stuck tool.
2Loss of time
If the stuck downhole tool is left in place, then sidetracking operations can be avoided, but conventional cement plug methods cannot achieve proper isolation
Solution Approach 1:
The sacrificial bridge plug is designed as a disposable tool that is set temporarily to enable cement placement, then discarded after serving its purpose. It is sacrificed by being pushed into the formation or breaking apart as cement sets around it, allowing proper isolation without requiring recovery. This temporary tool enables the permanent solution (cement plug) while avoiding sidetracking.
3Ease of manufacture
If cement is squeezed across multiple reservoirs with the BHA in place, then cement can be placed, but isolation is insufficient as cement enters the highest permeable zone
Solution Approach 1:
The sacrificial bridge plug creates a localized cement placement zone around the stuck tool rather than allowing cement to flow freely across multiple reservoirs. By providing a specific path and displacement mechanism, it ensures cement is placed in the correct location with proper properties, achieving reliable isolation of specific formations.
Data Source
AI summary
A method includes conveying a sacrificial tool into a wellbore on a conveyance, the wellbore penetrating one or more subterranean formations and the sacrificial tool including an overshot fishing tool, a tubing operatively coupled to and extending from the overshot fishing tool, and a liner hanger arranged at an upper end of the tubing. An uphole end of a downhole tool is received within with the overshot fishing tool, the downhole tool being stuck in the wellbore adjacent the one or more subterranean formations. The uphole end of the downhole tool is sealingly engaged, and a cement is subsequently circulated through the sacrificial tool and the downhole tool and discharged into an annulus defined between the downhole tool and an inner wall of the wellbore.