Subsea Deintensifier for Pressure Reduction
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Solution Overview
Problem
Conventional subsea accumulators become inefficient at deeper water depths due to increased hydrostatic pressure and lower temperatures, leading to larger and heavier equipment requirements, which increases the size and weight of subsea drilling equipment and reduces the efficiency of hydraulic fluid pressure for operating subsea equipment.
Innovation Solution
The implementation of a deintensifier that reduces pressure in one or more chambers of a hydraulic device, thereby reducing the fluid pressure required to operate the device, allowing for a corresponding reduction in the size and weight of accumulators needed, and optimizing the use of high-pressure fluid for actual work rather than movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If accumulators are precharged to higher pressures to compensate for hydrostatic pressure at greater depths, then the differential pressure required to operate subsea equipment is maintained, but the accumulator size and weight must be increased to contain the higher precharge pressure
Solution Approach 1:
The system divides the pressure management function into two separate components: surface accumulators that store hydraulic fluid at moderate pressure, and a subsurface intensifier that boosts the pressure locally where needed. This segmentation allows the accumulators to be smaller and lighter while still achieving the required operating pressure at depth.
Solution Approach 2:
A hydraulic intensifier acts as an intermediary device between the surface accumulators and the subsea equipment. It takes the moderate pressure from the accumulators and intensifies it to the high pressure required for operation, eliminating the need to precharge accumulators at excessively high pressures.
2Stress or pressure
If accumulators are precharged to higher pressures to maintain differential pressure at depth, then equipment operation is enabled, but the volume of hydraulic fluid that can be stored is reduced due to compression
Solution Approach 1:
The system separates the storage function (performed by accumulators at surface with moderate pressure) from the pressure boosting function (performed by intensifier at depth). This allows maximum volume of hydraulic fluid to be stored at safe pressures, then intensified when needed.
Solution Approach 2:
The intensifier dynamically changes the pressure parameter of the hydraulic fluid, converting it from the moderate storage pressure in the accumulators to the high operating pressure required at depth, thereby maximizing the usable volume of stored fluid.
3Quantity of substance
If larger accumulators are used to provide sufficient fluid volume at high pressure, then the hydraulic fluid volume required for operation is sufficient, but the size and weight of subsea equipment increases
Solution Approach 1:
The system divides the volume requirement between surface accumulators (which can be larger without affecting subsea equipment size) and compact subsurface intensifier components. This allows sufficient hydraulic fluid volume to be provided without increasing the size of subsea equipment.
Solution Approach 2:
The solution moves the bulk storage volume to the surface dimension, separating it from the subsea equipment volume. Large accumulators can be positioned on the rig floor while the intensifier and associated high-pressure components occupy minimal subspace on the BOP stack.
4Reliability
If more and larger accumulators are installed to meet pressure and volume requirements at depth, then operational performance is maintained, but the complexity of rig equipment for transport and handling increases
Solution Approach 1:
The system combines the functions of multiple large accumulators and a pressure boosting mechanism into a single integrated intensifier unit that can be transported and installed as one package, reducing the complexity of rig equipment requirements.
Solution Approach 2:
The intensifier serves as an intermediary that simplifies the overall system by replacing the need for multiple large accumulators with a single compact device that performs both storage and pressure boosting functions.
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 deintensifier reduces the pressure and force required to operate subsea equipment, alleviating the need for larger accumulators and allowing for more efficient use of hydraulic fluid, thereby minimizing equipment size and weight while maintaining operational performance.
Implementation Method 1
a deintensifier, which reduces pressure in one or more chambers of a hydraulic device
Implementation Method 2
The gas section is precharged with a gas at a pressure equal to or slightly below the anticipated minimum pressure required to operate the subsea equipment. As working fluid is added to the accumulator in the separate hydraulic fluid section, the volume of that section increases. In turn, the volume of the gas section is reduced, thus increasing the pressure of the gas and the hydraulic fluid.
Implementation Method 3
Accumulators operate on a common principle: The gas section is precharged with a gas at a pressure equal to or slightly below the anticipated minimum pressure required to operate the subsea equipment. As working fluid is added to the accumulator in the separate hydraulic fluid section, the volume of that section increases. In turn, the volume of the gas section is reduced, thus increasing the pressure of the gas and the hydraulic fluid.
Implementation Method 4
the efficiency of conventional accumulators decreases in deeper waters because hydrostatic pressure and lower temperatures can cause the non ideal gas to compress, leaving a progressively smaller amount of useable volume of hydraulic fluid to power the subsea equipment's functions
Data Source
AI summary
A system for reducing pressure in a subsea operator. In one embodiment, a subsea system includes an operator and a deintensifier. The operator includes a housing and a piston. The piston is movably disposed within the operator housing and divides an inner volume of the operator housing into a closing chamber and a second chamber. The deintensifier is fluidically coupled to the operator. The deintensifier includes a housing and a piston. The piston includes a closing surface and an opening surface. The closing surface is fluidically coupled to the second chamber of the operator housing. The opening surface is fluidically coupled to ambient pressure. The area of the closing surface is greater than an area of the opening surface so as to increase the pressure differential between the closing chamber and the second chamber and assist in moving the operator piston to the closed position.