Surge Reduction System for MPD Liner Casing Operations
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Solution Overview
Problem
Managed Pressure Drilling (MPD) systems face challenges in reducing surge pressure when running liner casing strings, which can lead to formation fracturing and mud losses, as existing surge reduction tools are inadequate in maintaining control of surface pressure and cleanliness during casing operations.
Innovation Solution
A system comprising auto-fill float equipment, drillpipe diverters, and flow restrictors is used to control surge pressure by allowing displaced fluid to flow through the auto-fill float equipment and diverters into the annulus, while the flow restrictor blocks fluid flow up the drillpipe, maintaining well control and rig cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If casing string is lowered into wellbore with close fit between OD of casing and ID of wellbore, then casing can be run to bottom of wellbore, but surge pressure increases causing formation fracturing
Solution Approach 1:
The patent introduces a drill pipe diverter as an intermediary device that provides an alternate flow path for drilling fluid. The diverter redirects fluid from the restricted annular space between the casing and wellbore into the drill pipe, thereby mediating the surge pressure problem and enabling safe casing running to bottom
2Object-affected harmful factors
If drill pipe diverter is used to redirect fluid flow, then surge pressure is reduced, but fluid flows into annulus compromising well control and rig cleanliness
Solution Approach 1:
The patent employs dynamically controllable flow paths through actuated valves and adjustable diverters. The system can switch between different flow configurations - redirecting fluid during casing running to reduce surge pressure, then closing the diverter and opening the RCD to restore normal MPD operations and maintain well control
Solution Approach 2:
The system temporarily discards normal well control procedures during casing running by allowing fluid to diverter into annulus, then recovers well control by closing the diverter and reopening the RCD to restore the closed-loop MPD system
3Object-affected harmful factors
If conventional surge reduction tools are used alone, then surge pressure is reduced, but control of surface pressure is lost
Solution Approach 1:
The patent merges conventional surge reduction tools (drill pipe diverter) with MPD system components (RCD, surface backpressure line) into an integrated system. This combination allows simultaneous surge pressure reduction through the diverter and surface pressure control through the RCD, achieving both objectives together
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 system effectively reduces surge pressure, prevents formation fracturing, and maintains well control and cleanliness during liner casing operations, allowing for successful running of liner casing strings to the bottom of the wellbore without fracturing the formation.
Implementation Method 1
auto-fill float equipment coupled to a lower end of the liner casing string and configured to allow fluid flow from the wellbore into the liner casing string
Implementation Method 2
drillpipe diverter attached to the drill pipe landing string and comprising ports that, when open, provide a fluid flow path between an interior of the drillpipe string and an annulus defined between the drillpipe landing string and the wellbore
Implementation Method 3
drillpipe flow restrictor attached to the drill pipe landing string above the diverter and configured to selectively block the flow path from the top of the drill pipe landing string
Data Source
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AI summary
A system for controlling surge pressure and deployed into a wellbore drilled using a managed pressure drilling technique includes auto-fill float equipment (14) allowing flow into a liner casing string, a drillpipe diverter (18) providing a flow path between a drillpipe landing string (11) and an annulus, and a drillpipe flow restrictor (21) selectively blocking the flow path from the top of the drillpipe landing string (11) while allowing fluid to be displaced up the liner casing string (13) and into the annulus. The drillpipe flow restrictor (21) and the drillpipe diverter (18) are convertible to provide a flow path from the wellbore through the auto-fill float equipment (14) to a top surface while blocking flow through the diverter into the annulus. The auto-fill float equipment (14) is convertible to block the flow path from the wellbore into the liner casing string, while allowing fluid to flow from the liner casing string into the wellbore.