Casing Cutting Tool Wedge Removal for Wellbore Sealing
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Solution Overview
Problem
Current wellbore abandonment methods, such as cement squeeze and reaming, are inefficient in ensuring complete sealing due to potential gaps in cement contact with the formation rock, leading to potential fluid migration issues.
Innovation Solution
A casing cutting tool with fluid jet nozzles is used to remove sections of wellbore casing and cement, creating longitudinal and transverse cuts to form wedges that are dislodged, exposing the formation rock, allowing for direct cement plug placement and enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement squeeze is used to seal the wellbore, then the wellbore can be plugged for abandonment, but the cement may not fully contact the surrounding formation due to narrow passages, compromising the sealing effectiveness
Solution Approach 1:
The cutting tool segments the casing and cement into removable wedges by making longitudinal and transverse cuts. This segmentation allows complete removal of the casing-cement complex, enabling direct cement plug contact with the formation rock without being blocked by the narrow annular passage between concentric casing strings.
Solution Approach 2:
The invention extracts the casing and cement from the wellbore by cutting and removing wedges. This extraction eliminates the barrier that prevents direct cement-formation contact, allowing the cement plug to be placed in direct contact with the surrounding rock formation for reliable sealing.
2Reliability
If reaming is used to expose the surrounding rock formation, then direct cement contact can be achieved, but the process is time consuming and costly
Solution Approach 1:
The invention replaces the traditional mechanical reaming process with a jet cutting system. High-pressure fluid jets make longitudinal and transverse cuts through the casing and cement, creating removable wedges. This substitution dramatically reduces operation time and cost while achieving the same goal of exposing the formation rock for direct cement contact.
Solution Approach 2:
The cutting tool uses high-pressure fluid jets (pneumatic/hydraulic system) to cut through the casing and cement. This hydraulic cutting mechanism is significantly faster and more efficient than mechanical reaming, reducing operation time and cost while effectively exposing the formation rock.
3Adaptability or versatility
If multiple strings of casing are present, then the wellbore can be completed with concentric casing strings, but the annular area between them forms fluid migration paths that are difficult to seal
Solution Approach 1:
The cutting tool segments the concentric casing strings and surrounding cement into removable wedges. By making longitudinal cuts through all casing strings and transverse cuts at offset locations, the tool creates discrete wedge sections that can be removed, exposing the formation rock and eliminating the annular fluid migration paths between concentric casings.
Solution Approach 2:
The invention extracts the problematic annular space between concentric casing strings by removing wedges containing the casing and cement. This extraction eliminates the fluid migration pathways that exist in the annular area, allowing direct placement of cement plugs in contact with the formation rock for reliable fluid barrier creation.
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 method effectively exposes the formation rock for direct cement contact, ensuring a permanent seal and reducing the time and cost associated with reaming processes.
Implementation Method 1
ejecting fluid from the one or more nozzles and thereby forming a plurality of longitudinal cuts through the at least one casing string and cement
Data Source
AI summary
A method includes conveying a casing cutting tool into the wellbore lined with at least one casing string and cement, and stroking the casing cutting tool over a predetermined axial length of the wellbore while ejecting fluid from one or more nozzles in the casing cutting tool and thereby forming a plurality of longitudinal cuts through the casing string and cement. The casing cutting tool is then rotated about its longitudinal axis at two or more axially offset locations along the predetermined axial length while ejecting fluid from nozzles and thereby forming a plurality of axially offset transverse cuts in the casing string and the cement. The longitudinal cuts and axially offset transverse cuts form wedges in the wellbore, and the wedges are dislodged from the wellbore to expose formation rock along the predetermined axial length.