Downhole Float Valve Retainer for Self-Filling Drill Strings
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Solution Overview
Problem
Current downhole drilling operations face challenges with check or float valves that prevent self-filling of the drill string, requiring top-filling to prevent collapse due to hydrostatic pressure, and existing solutions either require activation devices or do not effectively manage fluid flow during drilling operations.
Innovation Solution
A downhole apparatus with a float valve retainer that maintains the float valve in an inoperable configuration until exposed to a selected absolute pressure, allowing the string to self-fill and then reconfigures to prevent reverse flow, utilizing a flow restriction and activating device to create a pressure differential for valve operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a check valve is provided in the drill string to prevent reverse flow, then reverse flow prevention is improved, but self-filling capability deteriorates
Solution Approach 1:
The float valve is designed to be dynamically controllable, transitioning between inactive (held open) and active (closed) states. The retainer mechanism allows the valve to be held in an open position during self-filling operations, then activated to close and prevent reverse flow when drilling fluid is pumped through the string.
Solution Approach 2:
The float valve is preliminarily held in an open configuration by the retainer mechanism before drilling operations begin. This preliminary state allows the drill string to self-fill with drilling fluid as it is tripped into the borehole. The valve is then activated to close, preparing the system for reverse flow prevention during subsequent drilling operations.
2Ease of operation
If the float valve is initially held open to allow self-filling, then self-filling capability is improved, but reverse flow prevention deteriorates
Solution Approach 1:
The system dynamically transitions the float valve from an open state during self-filling to a closed state during drilling operations. The retainer mechanism enables this dynamic control, holding the valve open initially, then allowing it to close when drilling fluid is pumped through the string, thereby providing reverse flow prevention when needed.
3Adaptability or versatility
If a retainer mechanism is added to control the float valve, then valve control flexibility is improved, but device complexity increases
Solution Approach 1:
The retainer mechanism utilizes hydraulic pressure from drilling fluid pumped through the string to actuate the float valve closure. The hydraulic pressure differential created during pumping operations provides the force needed to move the retainer and close the valve, eliminating the need for complex mechanical actuation systems.
Solution Approach 2:
The float valve retainer mechanism is designed to be self-actuating through the natural hydraulic pressure generated during drilling fluid circulation. When drilling fluid is pumped through the string, the pressure differential automatically triggers the valve closure without requiring external activation devices or complex control systems.
4Strength
If hydrostatic pressure is used to prevent string collapse, then structural integrity is improved, but top-filling requirement increases
Solution Approach 1:
The drill string is designed to self-fill with drilling fluid as it is tripped into the borehole. The float valve remains held open during this process, allowing fluid to flow into the string through the jetting nozzles in the drill bit, eliminating the need for external top-filling operations while maintaining structural integrity through hydrostatic pressure.
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
Enables self-filling of the drill string without the need for top-filling, allowing for efficient fluid management during drilling and reducing the requirement for activation devices, while maintaining control over fluid flow to prevent collapse and ensure safe operation.
Implementation Method 1
a float valve retainer maintaining the float valve in an inoperable configuration and permitting flow up through the tubular body until the retainer is exposed to a selected absolute pressure
Implementation Method 2
The float valve retainer may comprise a flow restriction to permit creation of a pressure differential across the restriction and reconfiguring of the retainer to permit operation of the float valve
Data Source
AI summary
Downhole apparatus (30) comprises: a tubular body (42) for incorporation in a tubing string (24); a float valve (30) mounted in the body (42) and operable to prevent flow up though the body; and a float valve retainer (38) maintaining the float valve (30) in an inoperable configuration and permitting flow up through the body (42), the retainer (38) comprising a flow restriction (80) to permit creation of a pressure differential across the restriction (80) and reconfiguring of the retainer (38) to permit operation of the float valve (30). The flow restriction (80) has a retracted configuration and an extended configuration to permit creation of the pressure differential, the flow restriction (80) maintaining the retracted configuration until exposed to a selected absolute pressure.