Pivotable Jetting Sub for Precise Wellbore Casing Erosion
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Solution Overview
Problem
Existing methods for repairing leaks or failures in cement columns of wellbores, such as using perforation guns and resin mixtures, can cause damage and require tripping casing strings out of the wellbore, which is difficult and costly, especially in smaller diameters.
Innovation Solution
A tool string with a jetting head and running and control tool that allows precise erosion of concentric casing strings and cement columns using abrasive fluids, enabling orientation and pivoting within the wellbore without tripping, utilizing anchoring tools for stabilization and a stroking tool for axial displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perforation guns and resin mixtures are used to repair leaks, then leak sealing can be achieved, but damage to surrounding area and geology occurs
Solution Approach 1:
The patent replaces the mechanical explosive-based perforation system with an abrasive fluid jetting system. The abrasive fluid is discharged through nozzles to erode and create access windows in the casing and cement column, eliminating the need for explosives and associated damage while achieving the same goal of accessing the annulus for repair.
Solution Approach 2:
The abrasive fluid acts as an intermediary medium between the tool and the casing/cement column. Instead of directly impacting with mechanical force or explosives, the abrasive fluid mediates the interaction by gradually eroding the material, reducing harmful effects on the surrounding geology while still achieving access for repair operations.
2Reliability
If perforation guns are used to form perforations, then leak sealing can be achieved, but weakening of surrounding geology occurs
Solution Approach 1:
The patent substitutes the high-impact mechanical perforation method with a controlled abrasive erosion process. The abrasive fluid jets gradually erode the casing and cement column to create access windows, avoiding the sudden mechanical impact and explosive forces that weaken the surrounding geology, thereby preserving structural strength while enabling repair access.
3Ease of operation
If casing strings are tripped out of the wellbore for repair, then precise intervention can be performed, but operational complexity and cost increase
Solution Approach 1:
The patent employs a dynamic, adjustable jetting system where the nozzle orientation can be changed during operation. The tool can pivot and reorient the abrasive fluid discharge direction to access different annuli and target areas, providing precise intervention capability without requiring the complex operation of tripping casing strings out of the wellbore.
4Ease of operation
If abrasive fluid jetting is used to erode casing and cement column, then access to annuli is achieved without tripping, but precise orientation control is required
Solution Approach 1:
The patent incorporates a dynamic orientation control mechanism that allows the jetting system to pivot and adjust its angle relative to the tool string. This dynamic capability enables precise targeting of different annuli and erosion zones while maintaining the benefit of accessing the wellbore without tripping casing strings, balancing operational ease with the complexity of orientation control.
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 precise access to casing-casing annuli for repair by selectively eroding casing strings and cement columns, reducing damage and cost by maintaining the tool string in place, thus addressing sustained casing pressure issues.
Implementation Method 1
discharging an abrasive fluid from one or more nozzles of a jetting head to erode a portion of a first one of the concentric casing strings and/or cement columns
Implementation Method 2
pumping an abrasive fluid from a surface location to the tool string
Data Source
AI summary
A tool string for progressive milling of concentric casing strings and cement columns in a wellbore includes an anchoring tool mateable to a downhole end of a tubing and operable engage the at least one of the concentric casing strings and cement columns to lock a position of the anchoring tool within the wellbore, a jetting head arranged at a downhole end of the tool string and including one or more nozzles for discharging an abrasive fluid from the jetting head towards one or more of the concentric casing strings and/or cement columns of the wellbore, and a running and control tool interposing the anchoring tool and jetting head. The running and control tool is operable to adjust an orientation of the jetting head with respect to the anchoring tool within the wellbore.