Managed Pressure Drilling Back Pressure Vessel for Pump Failure
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Solution Overview
Problem
During managed pressure drilling (MPD) operations, sudden mud pump failure or loss of power can lead to a reduction or loss of equivalent circulating density (ECD), potentially causing borehole failure and well collapse due to unstable wellbore pressure.
Innovation Solution
A system and method that maintains constant bottom hole pressure and wellbore pressure profile by utilizing a pressure vessel with a compressed gas system to divert mud into the primary flowline, ensuring back pressure is maintained even in the event of mud pump failure or power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mud pump failure or power loss occurs during MPD operations, then the system loses the ability to maintain equivalent circulating density (ECD), but the borehole remains vulnerable to collapse and failure
Solution Approach 1:
The patent introduces an auxiliary back pressure pump as an intermediary device that can independently maintain back pressure when the primary mud pump fails. This auxiliary pump acts as a mediator between the drilling system and the wellbore, ensuring continuous pressure support and preventing borehole collapse during pump failures or power losses.
Solution Approach 2:
The system implements prior cushioning by having standby auxiliary pumps and power sources ready before failures occur. The auxiliary back pressure pumps are pre-positioned and can be activated immediately upon detecting primary pump failure, providing immediate pressure support to prevent borehole instability before damage occurs.
2Loss of energy
If fully automated MPD chokes close as fast as possible to trap residual pressure, then some pressure is retained, but the pressure is insufficient to prevent borehole failure
Solution Approach 1:
The patent merges the function of MPD chokes with auxiliary back pressure pumps to create a combined pressure maintenance system. The chokes provide initial rapid pressure retention while the auxiliary pumps provide sustained pressure support, creating a synergistic system that maintains adequate wellbore pressure strength that neither component could achieve alone.
Solution Approach 2:
The pressure maintenance system functions as a composite system combining mechanical choke devices with powered pump systems. This composite approach integrates passive pressure trapping (chokes) with active pressure generation (pumps) to achieve the full pressure levels needed to prevent borehole failure.
3Duration of action of stationary object
If a pressure vessel with compressed gas system is used to maintain back pressure, then constant pressure is maintained for a temporary period, but the system requires additional equipment and complexity
Solution Approach 1:
The patent employs pneumatic principles using compressed gas in a pressure vessel to maintain back pressure. The compressed gas acts as a energy storage medium that can be rapidly deployed to maintain pressure for a temporary period, providing extended operational capability during pump failures without requiring continuous external power sources.
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 prevents wellbore instability and potential collapse by maintaining a constant wellbore pressure profile for a temporary period, providing time to restore power or activate alternative pressure maintenance methods.
Implementation Method 1
a compressed gas system to pressurize the pressure vessel and divert the mud into the primary flowline
Data Source
AI summary
This system maintains bottom hole pressure and constant well bore pressure profile for a period of time in event of loss of power to rig pumps, rig pump failure or other loss of pressure to the primary flowline. The back pressure system diverts mud into the primary flowline to maintain pressure. The system provides time to get the diesel powered cement unit on line to maintain pressure or get the power reinstated to the rig pumps. The mud discharged into the primary flowline can be recovered back into the housing via the housing inlet line and the housing can be recharged via the N2 high pressure bottle rack. The back pressure system installs upstream of the MPD chokes with interfaces to the primary flow line to divert the drilling mud to the primary flowline.