Downhole Tubular Separation for Well Isolation
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Solution Overview
Problem
Existing well abandonment methods in Australia and Brazil are costly and inefficient, particularly in double-cased wells, as they require removing both inner and outer production strings and control lines, which is time-consuming and expensive, and often results in fluid leaks during cementing.
Innovation Solution
A downhole method involving a tool with a bit that machinesthe well tubular metal structure to create uncased openings without removing the upper part of the well tubular metal structure, allowing for in-situ creation of isolation by inserting an annular barrier and expanding it, and pouring cement through the opening, thus reducing the need for extensive string removal and minimizing leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner and outer production strings are pulled out to allow cement access, then the well can be properly abandoned and isolated, but the operation becomes expensive and time-consuming requiring big rig equipment
Solution Approach 1:
The invention extracts only the necessary portion of the production string (a section above the isolation point) rather than removing the entire string. The cutting tool creates openings at specific locations to allow cement access, while the majority of the production string remains in place, eliminating the need for expensive big rig operations.
Solution Approach 2:
The invention applies local quality by creating openings only at specific locations where cement access is needed, rather than removing the entire production string. The cutting tool makes localized openings in the production string at positions above the isolation point, allowing cement to reach the formation while leaving the rest of the string intact.
2Reliability
If the inner production string is pulled out to allow cement access, then isolation can be achieved, but the operation time increases significantly
Solution Approach 1:
The invention extracts only the minimal necessary material (localized openings in the production string) rather than removing the entire string. This dramatically reduces operation time while still achieving the required isolation, as the cutting tool creates small openings quickly without requiring lengthy string removal operations.
Solution Approach 2:
The invention skips the time-consuming step of complete string removal by using a cutting tool to create openings directly through the production string in place. This allows the operation to proceed much faster by rushing through the critical step of creating cement access paths without the lengthy process of pulling out the entire string.
3Object-affected harmful factors
If control lines are removed during string pullout, then fluid leak prevention is ensured, but the operation becomes more complex and costly
Solution Approach 1:
The invention extracts only the necessary openings in the production string rather than removing the entire string and associated control lines. The cutting tool creates openings that allow cement to pass through while the control lines remain clamped to the production string, eliminating the need for separate control line removal operations.
Solution Approach 2:
The invention merges the functions of creating cement access openings with maintaining control line integrity. By creating openings in the production string while leaving it in place, the control lines remain attached and functional, combining the benefits of cement access with continued control line operation without requiring separate removal operations.
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 simplifies and cost-reduces well abandonment by enabling faster and more efficient plugging and isolation without the need to remove the upper well tubular metal structure, reducing operational costs and ensuring regulatory compliance.
Implementation Method 1
separating a first section/upper part of the first well tubular metal structure from a second section/lower part of the first well tubular metal structure by machining into and along a circumference of the first well tubular metal structure
Data Source
AI summary
A downhole method for preparing and/or providing isolation at a predetermined position in an existing well includes inserting a downhole tool comprising a bit on a projection part in a first well tubular metal structure, positioning the downhole tool opposite the predetermined position, separating an upper part of the first well tubular metal structure from a lower part of the first well tubular metal structure, moving the downhole tool along the longitudinal extension in the upper part to a second position, and separating a first part of the upper part of the first well tubular metal structure from a second part of the upper part of the first well tubular metal structure, thus providing an uncased opening between the second part of the first section and the second section.