Subsea Barrier System for HPHT Well Pressure Isolation
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Solution Overview
Problem
Current subsea well systems are inadequate for high pressure high temperature (HPHT) wells, as they struggle to safely drill, complete, produce, and intervene on reservoirs with pressures exceeding 15,000 psi and temperatures above 350 degrees F, due to limitations in existing materials and equipment ratings.
Innovation Solution
A subsea system incorporating a controlled multiple barrier system, such as a high integrity pipeline protection system (HIPPS), which divides the system into sections rated for different pressure, temperature, and flow rate thresholds, allowing for enhanced development of HPHT reservoirs by isolating higher-rated components upstream and lower-rated components downstream of the barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional subsea well systems are used for HPHT wells, then the system structure remains simple and equipment is readily available, but the system cannot safely handle pressures exceeding 15,000 psi and temperatures above 350 degrees F
Solution Approach 1:
The subsea system is divided into multiple pressure-containing sections separated by barrier systems. The first section (upstream) is rated for high pressure/temperature HPHT conditions, while the second section (downstream) can be rated for lower pressures. This segmentation allows the overall system to handle HPHT conditions without requiring all components to be rated for maximum HPHT conditions, thus improving safety while managing complexity.
Solution Approach 2:
A barrier system acts as an intermediary between the high-pressure upstream section and the lower-pressure downstream section. This barrier isolates the high-pressure environment from downstream equipment, enabling the use of less complex, lower-rated materials in the flowline and riser while maintaining safety for HPHT operations.
2Reliability
If high pressure ratings are applied to all system components, then safety is improved, but cost and complexity increase significantly
Solution Approach 1:
Different sections of the system are assigned different pressure ratings based on their location and function. The upstream section near the wellhead uses high-pressure-rated components to contain HPHT conditions, while the downstream flowline and riser use lower-pressure-rated, less expensive materials. This local differentiation of quality allows cost-effective manufacturing while maintaining safety where it is most critical.
Solution Approach 2:
The system is segmented into pressure zones with different safety requirements. By isolating the high-pressure zone to only where necessary (upstream of the barrier), the patent reduces the total volume of expensive high-pressure-rated materials needed, thereby reducing overall cost while maintaining adequate safety margins.
3Object-affected harmful factors
If barrier systems are introduced to divide pressure zones, then downstream equipment is protected from HPHT conditions, but system complexity increases
Solution Approach 1:
A barrier system serves as an intermediary protective element between the HPHT environment and downstream equipment. This single barrier interface protects all downstream components from high pressure and temperature exposure, reducing the complexity of designing individual protection systems for each downstream component.
Data Source
AI summary
A subsea production system and method for installing the same are provided. The subsea production system includes a high pressure subsea wellhead, a tubing hanger landed proximate the wellhead, a production tree disposed above the wellhead downstream of the tubing hanger, a riser, a subsea flowline system coupled between the production tree and the riser, at least one barrier located downstream of the tubing hanger, and a secondary barrier valve disposed within the tubing hanger or in line with and upstream of the tubing hanger. The at least one barrier provides a pressure barrier that controls pressure of fluid flowing from components of the subsea production system located upstream of the barrier to components of the subsea production system located downstream of the barrier, and the secondary barrier valve is remotely actuable between a closed position and an open position.