Downhole Float Tool With Wiper Plug Rupture Disk
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Solution Overview
Problem
The cementing process in well casing is challenged by cement displacement and prevention of backflow ('U-tubing') due to erosion of one-way valves in float tools, leading to potential leaks and remediation issues.
Innovation Solution
A downhole assembly with one or more one-way valves and wiper plugs, where the wiper plugs include a valve element to prevent uphole fluid flow and a rupture disk to allow downhole flow, ensuring effective cement displacement and prevention of backflow without valve erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one-way valves are used in float tools to prevent cement backflow, then cement displacement and backflow prevention are improved, but valve erosion occurs leading to potential leaks
Solution Approach 1:
The invention divides the float tool into separate functional components: a float collar with one-way valves for backflow prevention, and a float shoe with a valve element for cement displacement. This segmentation allows each component to perform its specific function optimally without the erosion issues affecting the entire system.
Solution Approach 2:
The invention extracts the valve element from the float shoe, making it a separate, removable component. This allows the valve element to be taken out and replaced when eroded, preventing leaks and maintaining system reliability without affecting the float collar's one-way valves.
2Adaptability or versatility
If float collar and float shoe are separated by lengths of casing, then assembly flexibility is improved, but shoe track remains causing lost well sections
Solution Approach 1:
The invention merges the float collar and float shoe into a close-coupled assembly with minimal separation. This eliminates the shoe track between them, ensuring that cement is fully displaced from the casing string through the float shoe without leaving unused sections in the well.
3Reliability
If valves in float collar and float shoe are used to prevent cement backflow, then backflow prevention is achieved, but cement flow through valves causes erosion and potential leaks
Solution Approach 1:
The invention treats the valve element in the float shoe as a disposable or easily replaceable component. When the valve element becomes eroded, it can be replaced rather than requiring remediation of the entire float tool, extending the overall service life of the system while maintaining reliable backflow prevention.
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
The solution effectively displaces cement from the casing string into the annulus, prevents backflow, and reduces the risk of valve erosion, thereby minimizing lost time and expense associated with remediation efforts.
Implementation Method 1
a float tool configured to be connected to a casing string and including one or more one-way valves configured to permit fluid flow in a downhole direction and to prevent fluid flow in an uphole direction
Implementation Method 2
The first wiper plug comprises a valve element that is configured to prevent fluid flow through the first wiper plug at least in the uphole direction
Implementation Method 3
deploying a first wiper plug through the casing string down to the float tool so as to displace at least some of the cement from the casing string into an annulus between the casing string and the well
Implementation Method 4
a second wiper plug that is configured to land on the first wiper plug, the second wiper plug including a rupture disk configured to block fluid flow through the second wiper plug. Upon rupturing the rupture disk, the second wiper plug permits fluid flow therethrough at least in a downhole direction
Data Source
AI summary
A downhole assembly includes a float tool configured to be connected to a casing string and including one or more one-way valves configured to permit fluid flow in a downhole direction and to prevent fluid flow in an uphole direction, and a first wiper plug configured to be deployed into a well via the casing string and engage the float tool. The first wiper plug comprises a valve element that is configured to prevent fluid flow through the first wiper plug at least in the uphole direction.