Sacrificial Overshot Tool for Cement Isolation Around Stuck Wellbore 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, especially when it spans multiple undesired reservoirs or production zones, preventing effective isolation and requiring sidetracking, which is costly and time-consuming.

Innovation Solution

A sacrificial tool comprising 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 proper isolation, with the tool and downhole tool left in place as the cement cures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional balanced cement plug methods are used with a stuck BHA in place, then the wellbore can be plugged, but the BHA prevents accessibility and the cement cannot be properly pumped across multiple reservoirs

Engineering Contradiction:

Improvewellbore isolationVSAvoidcement pumpability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention extracts the stuck BHA from the cementing operation by using a separate bridge plug that can be set independently of the BHA. The bridge plug is deployed on a separate conveyance and set below the BHA, allowing cement to be pumped around the BHA through the annulus between the bridge plug and wellbore wall, thus bypassing the obstruction entirely

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the dimension of cement flow by transitioning from axial flow through the BHA to radial flow in the annulus between the bridge plug and wellbore. This dimensional change allows cement to bypass the stuck BHA completely and achieve proper placement across multiple reservoir zones

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If cement is squeezed across undesired reservoirs with a stuck BHA in place, then the wellbore can be plugged, but the cement is squeezed into the highest permeable zone and fails to achieve required isolation

Engineering Contradiction:

Improvereservoir isolationVSAvoidcement placement control

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bridge plug acts as an intermediary device that controls cement placement. By setting the bridge plug below the stuck BHA and using its casing as a conduit, the invention mediates the cement flow path to ensure uniform distribution across all target reservoir zones rather than preferential flow into the highest permeability zone

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bridge plug is set in advance before cementing operations begin. This preliminary action establishes a controlled flow path and prevents uncontrolled cement squeeze into high permeability zones, ensuring proper isolation is achieved

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a sidetrack wellbore is drilled to abandon the stuck BHA, then the well can be abandoned, but it requires cutting the conveyance and is costly and time-consuming

Engineering Contradiction:

Improvewellbore abandonmentVSAvoidabandonment time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The invention converts the harmful situation of a stuck BHA into a beneficial outcome by using the BHA itself as a central obstruction around which to build the solution. The bridge plug is set around the BHA, and cement is pumped in the annulus, turning the obstruction into the center of a controlled isolation system that eliminates the need for sidetracking

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 effective cement isolation of subterranean formations, reducing the need for sidetracking and saving resources by ensuring proper reservoir isolation, even when a downhole tool is stuck, thus optimizing wellbore abandonment.

Implementation Method 1

receiving an uphole end of a downhole tool within with the overshot fishing tool, wherein the downhole tool is stuck in the wellbore adjacent the one or more subterranean formations, sealingly engaging the uphole end of the downhole tool

Methodology Applied

Scientific EffectSealing engagement:

Implementation Method 2

circulating a cement through the sacrificial tool and the downhole tool and discharging the cement into an annulus defined between the downhole tool and an inner wall of the wellbore

Methodology Applied

Scientific EffectCirculation: Convection

Data Source

PatentUS20250376910A1Sacrificial tool for plugging and abandoning a wellbore and methods thereof

Publication Date: 2025.12.11 SAUDI ARABIAN OIL CO

AI summary

A sacrificial tool for plugging and abandoning a wellbore includes an overshot fishing tool configured to locate and sealingly engage an uphole end of a downhole tool stuck within the wellbore, the wellbore penetrating one or more subterranean formations, a tubing operatively coupled to and extending from the overshot fishing tool, and a liner hanger arranged at an upper end of the tubing. Cement pumped to the sacrificial tool via a conveyance is conveyed to the downhole tool and discharged from the downhole tool into an annulus defined between the downhole tool and an inner wall of the wellbore to isolate the one or more subterranean formations.