Subsea Pressure Sensor Bias Determination via Isolated Fluid Conduit
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Solution Overview
Problem
Subsea pressure sensors, particularly quartz resonant sensors, suffer from drift due to aging and 'outgassing,' leading to inaccurate depth measurements in hydrocarbon reservoir monitoring, as they can misinterpret drift as real seafloor changes, necessitating regular calibration to ensure accurate data.
Innovation Solution
An in-situ pressure sensor bias determination apparatus comprising a measurement pressure sensor, a reference pressure sensor, and an electronically controllable pressure adjustment device, sealed within a fluid conduit network with an ambient access port, isolates ambient pressure to prevent oil and seawater ingress, allowing for precise bias determination without mechanical complexity or limited lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If in-situ calibration techniques using fluid conduits are employed, then measurement precision is improved, but reliability deteriorates due to oil and seawater ingress causing corrosion and fouling
Solution Approach 1:
The system is divided into two separate pressure sensing paths: one for measurement pressure sensors that remains isolated from the ambient environment, and another for reference pressure sensors that can be selectively exposed to ambient pressure through the fluid conduit network. This segmentation allows calibration without exposing the measurement sensors to corrosive environments.
Solution Approach 2:
A piston gauge calibrator serves as an intermediary device between the reference pressure sensors and the ambient environment. It transfers ambient pressure to the reference sensors through the fluid conduit network while maintaining a seal that prevents oil and seawater ingress into the housing, thus enabling calibration without direct exposure to corrosive elements.
2Measurement precision
If piston gauge calibrators are used for in-situ calibration, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The piston gauge calibrator is designed as a multi-functional device that can serve multiple pressure sensors simultaneously through the fluid conduit network. It can calibrate reference pressure sensors at different locations and depths without requiring separate calibration mechanisms for each sensor, thereby reducing overall system complexity.
Solution Approach 2:
The system replaces complex mechanical calibration mechanisms with a more simplified piston gauge design that uses hydraulic pressure transmission through the fluid conduit network. This substitution reduces mechanical complexity while maintaining calibration accuracy.
3Measurement precision
If reference pressure sensors are exposed to ambient pressure for calibration, then measurement precision is improved, but object-affected harmful factors increase due to corrosion and fouling
Solution Approach 1:
The fluid conduit network utilizes flexible sealing mechanisms and thin film barriers that allow pressure transmission while maintaining hermetic seals. These seals prevent seawater and oil from penetrating into the housing and contacting the reference pressure sensors, thus eliminating corrosion and fouling issues while enabling ambient pressure exposure for calibration.
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
This solution effectively reduces the bias error of measurement pressure sensors to match the accuracy of reference sensors, extending operational lifespan by preventing corrosion and fouling, and enabling accurate depth measurements beyond the reference sensor's range.
Implementation Method 1
a measurement pressure sensor; a reference pressure sensor
Implementation Method 2
The piston gauge calibrator is based upon a dead weight pressure principle of operation
Data Source
AI summary
An in-situ pressure sensor bias determination apparatus (300) comprises a measurement pressure sensor (400), a reference pressure sensor (402), an electronically controllable pressure adjustment device (406), and a fluid conduit network (410) having an ambient access port (412). The measurement pressure sensor (400) has a greater operating pressure range than the reference pressure sensor (402). The measurement pressure sensor (400), the reference pressure sensor (402) and the pressure adjustment device (406) are sealingly coupled to the fluid conduit network (410) so as to define a volume that is open only at the ambient access port (412). An ambient isolation device (420) is arranged to isolate selectively the ambient access port (412) from the measurement pressure sensor (400), the reference pressure sensor (402) and the pressure adjustment device (406), thereby closing the open volume.