Bladder Mud Pump Backpressure Control
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Solution Overview
Problem
Subsea drilling systems face delays in well control responses due to the reliance on fluid column pressure in the riser, which can be slow to react to anomalies like well kicks, as traditional mud discharge systems do not effectively manage backpressure.
Innovation Solution
A system comprising a mud pump with a bladder and pressure control circuit that maintains backpressure in the working fluid space to resist mud flow surges, using a series of pumps and a pressure control circuit to equalize pressure and manage mud flow, with optional control valves and flow meters for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional mud discharge systems are used, then the system structure is simple, but the well control response time is slow
Solution Approach 1:
The system pre-positions mud pumps and working fluid supply lines ready for immediate operation. The bladder pump is pre-configured with the chamber, bladder, and sealing arrangement so that when well control action is needed, the system can rapidly transition to pressurizing mud flow without delay. This preliminary preparation eliminates the need for slow sequential assembly or activation of components during emergency well control scenarios.
Solution Approach 2:
The patent introduces a working fluid (seawater or other fluid) as an intermediary medium to transmit pressure from the pump chamber to the mud flow. This working fluid acts as a mediator that enables rapid pressure transmission and control, allowing the system to respond quickly to well control needs without direct mechanical connection delays. The pressure control circuit uses this intermediary fluid to regulate and transmit force efficiently.
2Reliability
If the bladder pump chamber is sealed, then the mud space and working fluid space are isolated, but pressure equalization across valves becomes difficult
Solution Approach 1:
The pressure control circuit introduces a working fluid as an intermediary that bridges the isolated mud space and working fluid space. This intermediary fluid allows pressure to be equalized across valves while maintaining the physical seal integrity of the bladder pump chamber. The working fluid flows through the pressure control circuit to balance pressures without compromising the sealing arrangement.
Solution Approach 2:
The patent replaces direct mechanical pressure equalization mechanisms with a hydraulic/fluid-based pressure control circuit. Instead of using mechanical linkages or direct physical connections to equalize pressure, the system uses fluid flow through the pressure control circuit to achieve pressure balance. This substitution maintains the sealed chamber configuration while enabling effective pressure equalization.
3Productivity
If working fluid is supplied continuously, then the mud lifting operation is continuous, but backpressure control becomes unstable
Solution Approach 1:
The pressure control circuit incorporates feedback mechanisms to monitor and regulate backpressure in real-time. When backpressure deviates from the desired level, the system automatically adjusts the working fluid supply or discharge to restore stable backpressure. This feedback control allows continuous mud lifting operation while maintaining stable backpressure conditions through dynamic adjustment.
Solution Approach 2:
The system uses dynamic control of the working fluid supply and discharge to adapt to changing operational conditions. The pressure control circuit can dynamically adjust flow rates, valve positions, and pump operations to maintain stable backpressure despite variations in mud flow conditions. This dynamic approach enables continuous operation with stable backpressure control.
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 enables faster and more controlled mud lifting and pressurization, reducing the risk of uncontrolled influxes and enhancing well control response times by maintaining backpressure and equalizing pressures across valves.
Implementation Method 1
a bladder mounted in the housing having a side in contact with the water space and an opposing side in contact with the mud space. Where the bladder defines a flow barrier between the water and mud space
Implementation Method 2
the pressure control circuit selectively equalizes pressure in portions of the lead line on opposite sides of the inlet valve
Implementation Method 3
a mud pump in fluid communication with a flow of mud from the subsea wellbore, a working fluid supply line in communication with the mud pump
Implementation Method 4
selectively communicating the downstream end of the pressure control circuit with the working fluid discharge line maintains a back pressure in the working fluid space to resist a surge of mud flow into the mud space
Data Source
AI summary
A method and system for lifting drilling mud from subsea to a drilling vessel includes a pump having a body with a chamber, and a bladder in the chamber. The bladder spans the chamber to define water and mud sides in the chamber. A mud inlet valve allows mud into the mud side of the chamber; which moves the bladder into the water side and urges water from the water side of the chamber through a water exit valve. Pressurized water enters the chamber through a water inlet valve, which in turn pushes the bladder and mud from the chamber through a mud exit valve. The bladder separates the mud and water as it reciprocates in the chamber. A pressure control circuit equalizes pressure across the water valves, and a control valve provides a back pressure in a discharge of the pressure control circuit.