Casing Cutter Tool String for Single-Trip Well Abandonment
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Solution Overview
Problem
Current well abandonment methods require multiple trips into the well to create a cement plug and cut the casing, which is time-consuming and costly.
Innovation Solution
A method that combines cementing and casing cutting into a single trip by using a tool string with a casing cutter to deposit fluidised plugging material and cut the casing, allowing the upper casing length to be pulled out on the same trip, thereby eliminating the need for additional trips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple trips are made into the well to create cement plug and cut casing separately, then each operation can be performed with dedicated tools, but the total time and cost increase significantly
Solution Approach 1:
The patent combines cementing and casing cutting operations into a single integrated tool string that can deposit cement plug and cut the casing in one trip. The tool string includes both a cementing device and a casing cutter with multiple blades, allowing both functions to be performed sequentially during a single well intervention, thereby eliminating the need for multiple separate trips.
Solution Approach 2:
The tool string is designed as a multi-functional device that can perform cementing, casing cutting, and potentially other operations within a single intervention. The universal design allows the same tool assembly to execute multiple tasks that traditionally required separate specialized tools, reducing overall intervention time while maintaining operational reliability.
2Ease of operation
If a standard casing cutter with central bore is used, then fluid pressure can actuate the cutting blades, but cement pumping through the tool body would damage the blades and inhibit cutting action
Solution Approach 1:
The tool body is segmented into separate flow paths: one for cement passage and another for actuating the cutting blades. The cement flows through dedicated channels that bypass the cutting blade assembly, while a separate fluid pressure system actsuates the blades for cutting. This segmentation prevents cement from contacting the delicate cutting blades while maintaining independent actuation capability.
Solution Approach 2:
A separate actuating fluid serves as an intermediary between the control system and the cutting blades. Instead of pumping cement through the tool body, a different fluid is used to transmit hydraulic pressure to the blade actuation mechanism, mediating the force transmission without exposing the blades to damaging cement materials.
3Device complexity
If cement is pumped through the tool body with cutting blades, then the tool can be simple in design, but the cement flow would damage the blades and prevent proper cutting
Solution Approach 1:
The tool body structure is segmented into distinct functional zones with separate flow channels for cement and actuating fluid. The cement flow path is routed through the tool body without intersecting the cutting blade assembly, while a separate hydraulic circuit provides blade actuation. This segmentation increases structural complexity but preserves cutting functionality and blade integrity.
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 reduces the number of trips required, saving time and costs while ensuring a permanent barrier is formed to prevent fluid escape, meeting regulatory requirements.
Implementation Method 1
passing a fluidised plugging material through the casing cutter
Data Source
Figure 1a~1e
Figure 2
Figure 3
AI summary
Method and apparatus for single-trip cementing and casing cutting for well abandonment and slot recovery. A casing cutter is described which has a central through bore including a wall to isolate the cutting assembly from cement being passed through the casing cutter. The casing cutter is run in a cased well bore, cementing occurs through the casing cutter to form a cement plug and then the casing is cut. Embodiments of casing cutters are provided for parting an upper length of casing from a lower length of casing.