Downhole Drill String Valve System for Rapid Pressure Recovery
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Solution Overview
Problem
The time required to build up operating pressure in a drill string after adding a drill pipe is prolonged due to increased internal volume, fluid leakage, and increased frictional losses, especially at greater depths, affecting drilling efficiency and productivity.
Innovation Solution
A valve system that selectively opens and closes the fluid flow path in a drill string to retain pressure, using a combination of check valves and an actuator controlled by sensors and an accumulator to maintain pressure during pipe additions, allowing rapid recompression when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the drill string internal volume is increased to reach greater depths, then the drilling depth is improved, but the time required to build up operating pressure increases
Solution Approach 1:
The drill string is segmented into multiple sections with check valves positioned at intervals. When a section is isolated by closing check valves, the compressed fluid is retained in that segment, allowing pressure to be maintained without requiring the entire drill string volume to be pressurized from scratch. This segmentation enables faster pressure recovery after pipe additions.
Solution Approach 2:
Check valves are pre-positioned throughout the drill string before drilling begins. These valves are designed to automatically close when pressure differential exceeds a threshold, preemptively creating pressure-retaining segments. This preliminary arrangement ensures that when pipe additions occur, the pressure retention mechanism is already in place, eliminating delays associated with pressure rebuild.
2Ease of operation
If compressed gas is vented or drains through the drilling tool during pipe addition, then the supply valve can be reopened, but the fluid pressure reduces to ambient pressure
Solution Approach 1:
The check valve mechanism extracts the harmful effect of pressure loss by selectively isolating segments of the drill string. When the supply valve is closed during pipe addition, check valves prevent compressed gas from draining through the drilling tool, effectively removing the pressure loss pathway and retaining pressure in the isolated segment.
Solution Approach 2:
Check valves act as intermediary devices between the compressed gas supply and the drilling tool. These valves automatically close when pressure differential exceeds a threshold, mediating the pressure transmission and preventing direct drainage of compressed gas through the tool, thus maintaining pressure in the upstream segment.
3Length of stationary object
If the hole depth increases, then the drilling capability is improved, but the efficient operating pressure of the drilling tools increases due to frictional losses and hydrostatic head
Solution Approach 1:
The drill string is divided into pressure-retaining segments using check valves positioned at intervals. Each segment can maintain its own pressure independently, reducing the cumulative effect of frictional losses and hydrostatic head that would otherwise require increasingly high supply pressures at greater depths. This segmentation allows deeper drilling without proportionally increasing the required operating pressure.
4Adaptability or versatility
If the supply valve is closed during pipe addition, then the drill string can be extended, but the time taken for pressure to build to operating pressure increases
Solution Approach 1:
Check valves are pre-installed throughout the drill string and designed to automatically close when pressure differential exceeds a threshold. This preliminary arrangement ensures that when the supply valve is closed for pipe addition, the check valves are already in position to retain pressure in isolated segments, eliminating the time delay associated with pressure rebuild after valve reopening.
Solution Approach 2:
The check valves provide dynamic pressure retention by automatically closing when pressure differential exceeds a threshold and opening when pressure equalizes. This dynamic behavior allows the system to adapt to changing conditions during pipe addition, automatically maintaining pressure in segments without requiring manual intervention or complex control systems.
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
Reduces the time and energy required to reach operating pressure, enhancing drilling efficiency, reducing costs, and minimizing greenhouse gas emissions by optimizing fluid pressure management.
Implementation Method 1
The valve system is designed such that it can selectively open and close the fluid flow path to prevent the operating fluid from flowing to and out of the down hole tool... the time taken to build-up operational pressure within the drill string is reduced because the fluid does not now flow through the drilling tool
Implementation Method 2
This forms a pressure retention arrangement that is able to retain an above ambient pressure of the compressed fluid within a length of the fluid flow path after the flow of the operating fluid into the path has been turned OFF
Data Source
AI summary
A compressed fluid driven downhole system 12 comprises a drill string 16 forming a fluid flow path 20. The drill string 16 has an up hole end and a down hole end. A downhole tool 14, which is driven by compressed fluid is coupled to the downhole end of the drill string 16. A valve system 10 is coupled to the tubular at a location up hole of the downhole tool 14. The valve system 10 is operable to selectively: open the fluid flow path 20 allowing compressed fluid to flow to drive the downhole tool 14; and, close the fluid flow path 20 preventing compressed fluid from flowing to and out of the downhole tool 14. Therefore, when re pressurizing the drill string following the connection of a new drill pipe compressed fluid delivered down the dill pipe is prevented from flowing to through downhole tool and into hole until the valve system is opened. The valve system 10 may be controlled to open when the pressure of the compressed gas in the drill string up hole of the valve system reaches a threshold pressure. The threshold pressure may be greater than ambient downhole pressure and less than or equal to an operating pressure of the downhole tool.