Modified Liner Tie-Back for High-Pressure Well Control
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Solution Overview
Problem
Uncontrolled wells with high-pressure fluid leaks pose challenges in hydrocarbon production, as existing methods like bullheading and dynamic killing may not effectively stop fluid flow, especially in cases of cross-flow between high and low pressure zones, leading to environmental damage and reduced production.
Innovation Solution
A wellbore tool with a modified liner tie-back stem and unidirectional valve system is used to divert fluid flow away from leaks by providing a weight greater than the fluid force, allowing metal-to-metal contact and subsequent pumping of kill fluid to stop the flow, and then removing the tool for repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods like bullheading or dynamic killing are used to control uncontrolled wells, then fluid flow may be temporarily reduced, but they fail to effectively stop high-velocity cross-flow between high and low pressure zones
Solution Approach 1:
The patent introduces a mechanical intermediary device (the well control system with packer, bridge plug, and valve assembly) that physically separates and controls the cross-flow path between high and low pressure zones. This intermediary mechanism provides reliable flow control that direct pressure application methods cannot achieve.
Solution Approach 2:
The well control system segments the wellbore into isolated zones using a packer and bridge plug, creating distinct pressure zones that can be independently controlled. This segmentation allows the high-velocity cross-flow to be stopped by establishing a mechanical barrier that divides the continuous flow path.
2Object-affected harmful factors
If conventional well control methods are applied, then some fluid flow reduction may occur, but they cause environmental damage and reduce production due to inability to effectively stop cross-flow
Solution Approach 1:
The patent employs disposable plugging devices (bridge plug and packer) that are installed to stop cross-flow and then removed after serving their purpose. These temporary, sacrificial components effectively seal the leak and prevent environmental damage, allowing the well to be repaired and production restored without long-term impairment.
Solution Approach 2:
The system converts the harmful high-velocity cross-flow into a controlled situation by using the flowing fluid itself to help set and seal the plugging devices, then channels any remaining flow through controlled paths that can be managed and directed to appropriate disposal or reinjection points, preventing environmental damage.
3Reliability
If a mechanical downhole plug is placed to control the well, then fluid flow can be stopped, but the complexity of installation and retrieval increases
Solution Approach 1:
The well control system is divided into separate, independently deployable components (packer, bridge plug, valve assembly) that can be installed in sequence through standard wellbore access. This segmentation allows each component to be handled and installed separately using conventional equipment, reducing overall installation complexity compared to a single complex plug device.
Solution Approach 2:
Instead of installing a complex plug from the surface that requires sophisticated deployment mechanisms, the system uses a simpler approach where the packer and bridge plug are set in reverse sequence (packer first, then bridge plug) and can be retrieved by simply pulling the conduit, inverting the conventional wisdom of complex deployment mechanisms.
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
Effectively stops fluid flow between high and low pressure zones, preventing environmental damage and allowing for safe repair of leaks, even in high-velocity cross-flow scenarios, by using the wellbore tool's weight and design to create a seal and divert fluid flow.
Implementation Method 1
an open downhole end of a wellbore tool having a weight at least equal to a second force greater than the first force on an uphole end of a second telescoping casing section
Implementation Method 2
The wellbore tool includes a unidirectional valve uphole of the open downhole end of the wellbore tool, the unidirectional valve prevents upward flow of the fluid towards the surface
Implementation Method 3
A kill fluid is pumped from the surface through an uphole end of the wellbore tool. The kill fluid provides a hydrostatic head sufficient to prevent the fluid from flowing in the uphole direction
Implementation Method 4
The wellbore tool further includes one or more O-rings attached to an outer surface of the modified liner tie-back stem. The method further includes additionally sealing the open downhole end of the wellbore tool against the uphole end of the second telescoping casing section using the one or more O-rings
Data Source
AI summary
One example of a wellbore control tool and a method of use is described. A leak is detected in a cased wellbore (102) comprising a multiple telescoping casing sections (104). A fluid flows in an uphole direction through the cased wellbore. A flow of the fluid in the uphole direction results in a first force in the uphole direction. The leak is in a first telescoping casing section (212). An open downhole end (206) of a wellbore tool (106) having a weight at least equal to a second force greater than the first force on an uphole end of a second telescoping casing section that is downhole from a location of the leak in the first telescoping casing section is seated. The open downhole end of the wellbore tool provides metal to metal contact against the uphole end (204) of the second telescoping casing section (208) and restricts fluid flow into the leak.