Integrated Bottom Hole Assembly for Single-Trip Casing Recovery
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Solution Overview
Problem
Current well abandonment methods require multiple trips into the well to cut and remove casing, which is time-consuming and costly, due to issues like binding materials in the annulus and limited pulling capacity, often necessitating additional clean-up trips to clear adhered materials.
Innovation Solution
A bottom hole assembly with a spear for gripping the inner casing, a cutting mechanism, and integrated clean-up tools, such as mills and jetting tools, allows for simultaneous cutting, pulling, and cleaning of the casing on a single trip, utilizing a hydraulic jack for enhanced pulling power and fluid management to clear adhered materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple trips are made to cut and remove casing, then complete casing recovery is achieved, but time and cost increase significantly
Solution Approach 1:
The patent combines cutting tools, pulling tools, and clean-up tools into a single integrated bottom hole assembly that can perform all operations in one trip. The cutting mechanism cuts casing sections, the pulling mechanism retrieves them, and the clean-up tools clear adhered materials simultaneously, eliminating the need for multiple separate trips.
Solution Approach 2:
The bottom hole assembly is designed as a multi-functional tool that performs cutting, pulling, and cleaning operations. The assembly includes a cutting mechanism with blades, a pulling mechanism with grips, and clean-up tools with scrapers, all integrated into one device that can complete the entire casing recovery process in a single trip.
2Productivity
If cutting and pulling tools are used without integrated clean-up, then casing removal is achieved, but adhered materials block the bore and require additional clean-up trips
Solution Approach 1:
The patent integrates clean-up tools directly into the bottom hole assembly with cutting and pulling mechanisms. The clean-up tools include scrapers and brushes that remove adhered materials from the casing inner surface and bore wall during the same trip as casing removal, preventing blockages and eliminating the need for separate clean-up trips.
Solution Approach 2:
The clean-up tools operate continuously during the casing removal process, clearing adhered materials as the casing is cut and pulled. This continuous cleaning action prevents material accumulation that would otherwise block the bore and require additional trips for clean-up operations.
3Productivity
If traditional cutting and pulling methods are used, then casing can be recovered, but limited pulling capacity requires cutting casing into shorter lengths
Solution Approach 1:
The patent combines cutting mechanisms that can sever long casing sections with pulling mechanisms having sufficient capacity to retrieve them in one operation. The integrated assembly includes multiple cutting blades positioned at different locations and a powerful pulling mechanism that can handle the full weight of cut sections, eliminating the need to cut casing into shorter lengths for multiple trips.
4Reliability
If separate clean-up trips are made, then adhered materials are removed, but time and operational costs increase
Solution Approach 1:
The patent merges clean-up operations with the primary casing removal trip by integrating scrapers, brushes, and jetting tools into the bottom hole assembly. These tools clear adhered materials from the bore and casing surfaces during the same operational trip, ensuring bore clearance without requiring separate clean-up trips and thereby reducing time and operational costs.
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
This approach reduces the number of trips required for casing recovery by integrating clean-up operations with cutting and pulling, enhancing efficiency and reducing costs by performing these tasks in a single operation while ensuring effective material removal from the wellbore.
Implementation Method 1
a hydraulic jack configured to apply a pulling force to the inner casing
Implementation Method 2
at least one jetting tool configured to jet high velocity fluid onto adhered materials within the annulus
Implementation Method 3
The at least one first clean-up tool is a mill, the mill comprising a cylindrical body with an abrasive outer surface
Data Source
AI summary
A method and apparatus for casing recovery in which a clean-up of the inside of the outer casing above the inner casing is performed on the same trip in the wellbore as cutting and pulling a section of the inner casing. A bottom hole assembly including a spear, a casing cutter and at least one clean-up tool is described. An embodiment of a clean-up tool being a jetting sub which can jet fluid radially to wash the outer casing and selectively allow fluid to pass through the sub at different pressures is described. The jetting sub can be used to control operation of other tools in the bottom hole assembly such as the casing cutter and a hydraulic jack.