Downhole Ported Shifting Sleeve for Pump Removal
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Solution Overview
Problem
The existing methods for removing downhole pumps from hydrocarbon production wells require 'killing' the well to prevent pressurized fluids and gases from escaping, which is costly, time-consuming, and can lead to permanent well damage or inability to restore the well to its original state, especially in heavy oil formations with abrasive sand.
Innovation Solution
A downhole apparatus featuring a ported sleeve that allows the well to be temporarily sealed, enabling the removal of the pump without releasing pressurized fluids and gases to the surface, by shifting the sleeve to a sealing position between the circumferential seals and uncoupling from the pump assembly during removal, thus maintaining well integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the downhole pump is removed for servicing or replacement, then the pump can be repaired or replaced, but the well must be killed to prevent pressurized fluids and gases from escaping to the surface
Solution Approach 1:
The sealing system is divided into multiple independent sealing elements: seal rings on the pump assembly, a seal sub with lower and upper circumferential seals, and a ported shifting sleeve. This segmentation allows the sealing function to be distributed across multiple components, enabling the pump to be removed while maintaining well containment through the coordinated action of these separate sealing elements.
Solution Approach 2:
The ported shifting sleeve acts as an intermediary element between the pump assembly and the wellbore. It includes a port that can be positioned to communicate with the wellbore or sealed off, serving as a mediator that allows pump removal while preventing fluid escape. The sleeve intermediates the transition from pump-operational state to pump-removed state, maintaining containment throughout the process.
2Object-affected harmful factors
If the well is killed by pumping viscous fluids downhole, then pressurized fluids and gases are sealed, but the process is costly and time-consuming
Solution Approach 1:
The seal sub and ported shifting sleeve are pre-installed and positioned in the wellbore before pump removal. The sealing elements are already in place and ready to engage, eliminating the need for time-consuming well killing operations. The ported shifting sleeve is pre-configured with ports that can be sealed or opened as needed, allowing immediate containment when the pump is removed.
Solution Approach 2:
The sealing system is designed to be self-actuating through the movement of the ported shifting sleeve. As the sleeve moves to seal off the port, the sealing action is automatic and does not require external intervention or complex well killing procedures. The system serves itself by using the pump removal motion to automatically engage the sealing elements and close the port.
3Object-affected harmful factors
If the well is killed using viscous fluids, then containment is achieved, but the well may be permanently killed or unable to be restored
Solution Approach 1:
The sealing function is extracted from the well killing process and embodied in the permanent installation of the seal sub and ported shifting sleeve. These components are left in the wellbore as a permanent sealing mechanism, separating the containment function from the temporary well killing operation. This extraction ensures that containment is achieved through engineered components rather than temporary fluid barriers that may cause permanent damage.
Solution Approach 2:
The system changes the physical state and position of the ported shifting sleeve to control sealing. By moving the sleeve to different positions (open port vs. sealed port), the system transitions between containment and flow states without requiring well killing. This parameter change approach allows reliable, reversible containment that does not damage the well or prevent restoration.
4Ease of repair
If seal rings are disengaged to remove the pump, then the pump can be accessed, but pressurized fluids and gases are released to the surface
Solution Approach 1:
The seal sub with its lower and upper circumferential seals is nested within the pump assembly structure. The ported shifting sleeve is nested within the seal sub. This nested arrangement allows multiple sealing functions to be packed into a compact configuration, enabling pump removal while maintaining containment through the coordinated sealing action of these nested elements.
Solution Approach 2:
The ported shifting sleeve is designed to be movable, transitioning dynamically between an open position (allowing fluid flow during pump operation) and a sealed position (preventing fluid escape during pump removal). This dynamic positioning allows the system to adapt its sealing behavior based on the operational state, maintaining containment when needed while allowing pump access when required.
Data Source
AI summary
A pump assembly for recovering hydrocarbons from downhole wells. The pump assembly comprising a seating surface adapted to sealingly engage an interior surface of a first circumferential seal means situated within production tubing when said pump assembly is in a downhole operative position. A downhole ported sleeve is further provided and comprises a first port means and a second port means. The ported sleeve is adapted to move within a seal sub comprising a lower seal means and an upper seal means. The first port means is positioned between the lower seal means and the upper seal means when the pump assembly is removed from the well, thereby preventing pressurized fluids and/or gases from reaching surface. A method for sealing a well upon removal of a pump is further disclosed.