Multi-Stage Flow Device for Wellbore Pressure Control
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Solution Overview
Problem
Current methods for removing well casing in oil and gas operations are time-consuming and expensive due to the need for multiple trips to cut and retrieve casing segments, often hindered by cement and barite settling, requiring separate cutting and extraction tools and multiple cuts to retrieve extended lengths of casing.
Innovation Solution
A multi-stage flow device with a housing, sleeve, and burst discs is used to control pressure within the wellbore annulus, allowing for a single trip to make multiple casing cuts and retrieve casing segments by activating tools with drop balls to manage fluid flow and pressure, enabling efficient cutting and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate cutting and extraction tools are used with multiple trips, then casing can be removed, but operational time and cost increase significantly
Solution Approach 1:
The patent combines the cutting tool and extraction tool into a single integrated tool string that can perform both functions sequentially during one continuous operation. The cutting device cuts the casing at the desired depth, and the spearing device immediately engages and extracts the cut casing segment without requiring the tool string to be retrieved and re-lowered, thereby eliminating multiple trips and reducing rig time
Solution Approach 2:
The cutting device performs the cutting action at the desired depth before the spearing device engages the casing. This preliminary cutting action prepares the casing for immediate extraction by the spearing device, enabling a seamless transition between cutting and extraction functions within a single trip
2Ease of operation
If multiple cuts are performed to retrieve extended casing lengths, then complete casing removal is achieved, but operational complexity and time increase
Solution Approach 1:
The patent divides the casing into multiple segments that can be cut and extracted sequentially. The tool string is designed to cut one segment, extract it, then proceed to cut and extract the next segment in sequence. This segmentation approach allows complete removal of extended casing lengths while maintaining a relatively simple operational procedure through the integrated tool design
3Ease of operation
If pressure control is not managed during spearing operation, then extraction can proceed, but wellbore pressure instability and fluid stripping occur
Solution Approach 1:
The patent incorporates a flow sub with burst discs that provide pressure feedback control during the spearing operation. The burst discs are designed to burst at specific pressure thresholds, automatically releasing pressure when it exceeds safe limits. This feedback mechanism prevents pressure instability and fluid stripping while allowing the spearing operation to proceed effectively
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 solution reduces the number of trips required, increases efficiency, and decreases operational costs by allowing multiple casing cuts and retrievals in a single operation, while maintaining wellbore pressure control and preventing stripping of drilling fluids.
Implementation Method 1
The first burst disc may be in fluid communication with the first flow passage, while the second burst disc may be in fluid communication with the second flow passage, and may have a higher burst pressure than the first burst disc
Implementation Method 2
The sleeve may have a ball seat, as well as first and second flow passages through the sleeve
Data Source
AI summary
A multi-stage flow sub usable in wellbore operations provides for flow of fluid from a tool string to a wellbore annulus, and may provide for one or more of controlling wellbore pressure during a tool operation, or preventing stripping of wet string. The multi-stage flow sub may include a housing having an axial bore and at least one flow passage. A sleeve within the housing may have an axial bore, a shoulder acting as a ball seat, and first and second axially offset flow passages. A first burst disc may be in fluid communication with the first flow passage, and a second burst disc may be in fluid communication with the second flow passage, the second burst disc having a higher burst pressure than the first burst disc.