Subsea Production Control System Research Articles

Combinatorial reasoning-based abnormal sensor recognition method for subsea production control system

The subsea production system is a vital equipment for offshore oil and gas production. The control system is one of the most important parts of it. Collecting and processing the signals of subsea sensors is the only way to judge whether the subsea production control system is normal. However, subsea sensors degrade rapidly due to harsh working environments and long service time. This leads to frequent false alarm incidents. A combinatorial reasoning-based abnormal sensor recognition method for subsea production control system is proposed. A combinatorial algorithm is proposed to group sensors. The long short-term memory network (LSTM) is used to establish a single inference model. A counting-based judging method is proposed to identify abnormal sensors. Field data from an offshore platform in the South China Sea is used to demonstrate the effect of the proposed method. The results show that the proposed method can identify the abnormal sensors effectively.

Optimization of subsea production control system layout considering hydraulic fluid pressure loss

Historically, layout optimization of the Subsea Production Control System (SPCS) has primarily emphasized equipment construction costs, frequently overlooking the influence of the seabed's three-dimensional terrain on hydraulic pressure loss during power distribution. Such neglect can escalate maintenance costs throughout the oil and gas field's lifespan. This article presents an advanced SPCS layout optimization approach that addresses hydraulic pressure loss. A multi-objective optimization model, accounting for the intricate seabed three-dimensional terrain and obstacles, was developed for the multi-level Star-Tree structured SPCS. This model integrates parameters such as construction costs, pressure loss, and pipeline routes. By merging the strengths of NSGA-II (Non-dominated Sorting Genetic Algorithm II) and Lazy Theta*, a novel hybrid algorithm has been proposed. This algorithm is adapted at determining the optimal position for the Subsea Distribution Unit (SDU), refining the pipeline connectivity topology, and minimizing pressure loss, thereby identifying superior laying paths. In a case study featuring an SPCS with 20 Subsea Control Modules (SCM) and one Floating Production Storage and Offloading (FPSO) unit, the method's efficacy in reducing hydraulic pressure loss was demonstrated in simulation results. The findings of this research hold promise as a pivotal decision-making instrument during the SPCS design phase, providing profound theoretical insights for layout design.

Cross-validation enhanced digital twin driven fault diagnosis methodology for minor faults of subsea production control system

A subsea production system is essential for the subsea production of oil and gas. Real-time monitoring can ensure safe production. A subsea production control system is the core of the subsea production system and the top priority to be monitored. Minor faults refer to faults with weak characteristics and are difficult to be found. They are common and pose significant risks in subsea production system. Safe operation of the system can be guaranteed to the greatest extent with a timely detection and handling of minor faults. Digital Twin driven fault diagnosis is an effective method to monitor the subsea production control system. However, the combination of digital twin and fault diagnosis is not comprehensive, especially in data interaction. It leads to the fact that digital twin cannot improve fault diagnosis accuracy significantly, mainly when a minor fault occurs. A cross-validation enhanced digital twin-driven fault diagnosis methodology for minor faults of the subsea production control system is proposed to achieve high accuracy. Control, loss and fault parameters are presented and used for building a digital twin model. Bayesian Networks are used to construct a fault diagnosis model. Single and cumulative errors are used to measure the difference between digital twin models and physical systems. A verification feedback method is used to check the diagnosis results. Data of four days of a subsea production system in the South Sea of China is used to demonstrate the proposed methodology. The results show that the method can improve the diagnosis accuracy for minor faults effectively.

Wave Energy Converters Hold Key to Using Renewables for Subsea Power

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 210910, “Innovative Industry Lead Project for Renewables for Subsea Power,” by Ian R. Crossland, SPE, Mocean Energy; Paul Slorach, Verlume; and Andrea Caio, Mocean Energy, et al. The paper has not been peer reviewed. _ The levels of power required to operate an offshore oil and gas field with 100% renewable energy are such that even offshore wind is unlikely to cost-effectively provide the levels of uptime needed to maintain reliable production without some form of energy storage. Providing a combination of technologies to maintain a balanced renewable energy supply system is key. In the complete paper, the authors focus on the use of wave energy converters (WECs), in combination with energy storage, to deliver benefits when powering offshore assets in situ, especially when continuous power requirements are in the 10–100 kW range. Introduction In 2020, a UK industry collaborative project, Renewables for Subsea Power (RSP), was launched and co-funded by the Net Zero Technology Centre. RSP is a phased demonstration project involving three technology developers (Mocean Energy, Verlume, and Modus), a first-tier international services company (Baker Hughes), and a major North Sea operator (Harbour Energy). Given the focus on ramping up the energy transition, in 2022 another major North Sea operator (Serica Energy) and an autonomous resident vehicle supplier (Transmark Subsea), who replaced Modus, also joined the project as part of the final phase (Phase 3) of activities. RSP aims to develop a complete, fully integrated system for the provision of the following: - Low-carbon remote power and communications using a WEC as the effective power source - A subsea energy-storage system for power conditioning - Smooth and uninterruptable power delivery to subsea production control systems - Residential underwater vehicles for a variety of monitoring or maintenance activities Throughout the three phases of RSP, project partners will design, build, and test all elements of the combined system. Phase 1 consisted of a front-end engineering design (FEED) successfully completed in 2021. Phase 2 involved the building and onshore commissioning of various subsystems. Phase 3 is planned to culminate in offshore full-system deployment and trials during 2023. Benefits of Wave Energy At a macro level, ocean waves are a highly abundant source of energy. Technically extractable wave energy resources amounted to 5–23% of 2017 global electricity demand, for instance, and approximately seven times that of available tidal resources worldwide. With approximately 40% of the world’s population inhabiting coastal regions, waves also provide a relatively local source of power for many coastal communities and densely populated areas. As well as being energy-dense and abundant, wave resource is predictable, often days in advance compared with solar and wind. In addition, its daily and seasonal complementarity with other renewables is crucial to achieving a more-balanced grid.

An All-Electric Gate Valve Actuator for Subsea Production Control Systems, Part A: Prototype and Test

To bridge the gap that exists in the key equipment of the new subsea production control system, the all-electric subsea gate valve actuator, and exploit subsea oil and gas resources with high reliability and safety while saving energy, this paper proposes a novel concept prototype of an all-electric subsea gate valve actuator which has the key functions of a redundant drive, failsafe closing, auxiliary override, position indication, and low-power position holding. It satisfied the electrically-driven requirements of the subsea gate valves and achieved Safety Integrity Level 3. The prototype was developed and tested successfully. The all-electric subsea gate valve actuator is suitable for controlling subsea gate valves with various sizes and rated working pressures to minimize the power consumption for the purpose of keeping the valves open and safely closing them in the event of the electrical failure. An override and position-indicating mechanism is equipped for emergency operation and the visual indication of the status of subsea gate valves.

Digital twin-driven fault diagnosis method for composite faults by combining virtual and real data

The subsea production system is essential for the subsea production of oil and gas. Real-time monitoring can ensure safe production. The subsea production control system is the core of the subsea production system and the top priority to be monitored. Troubleshooting the subsea production system involves lifting the component to the platform to repair it. And then send it back subsea. There is no doubt that it is expensive. In this case, some faults will not be handled temporarily if they do not affect the system operation seriously. This leads to multiple faults existing simultaneously, resulting in mixed signals. That makes it difficult to distinguish the state of the subsea production system. Thus, a fault diagnosis method for composite faults is needed. A digital twin-driven fault diagnosis method for composite faults is proposed by combining virtual and real data. Bernoulli Equation combines loss, control, and state parameters to build a digital twin model. A cross-validation enhanced fault diagnosis method is applied to single faults. A Bayesian network-based fault diagnosis model combining virtual and real data is built for composite faults. Field data from an offshore platform in the South Sea of China is used to demonstrate the effect of the proposed method. The results indicate that the method is extremely effective for composite faults of the subsea production control system.

Integral Layout Optimization of Subsea Production Control System Considering Three-Dimensional Space Constraint

The subsea production control system, characterized by a complex and diverse structure and high cost, is one of the essential parts of a subsea production system. The rational layout of the subsea production control system is essential to reduce development costs and ensure safe production in offshore fields. Most previous studies on layout design in offshore fields have focused on the oil- and gas-gathering system. However, the layout of the subsea production control system has not thoroughly been researched to date and the seabed terrain and integral optimization have rarely been discussed. This paper focuses on the multi-layer star structure and multi-layer star-tree structure, two common layout structures of subsea production control systems, and establishes the corresponding model with obstacle and seabed terrain conditions. Obtaining the lowest possible total cost was the aim of the model. A hybrid algorithm combining the adaptive mutation particle swarm algorithm and the A-star algorithm was applied to integrally optimize the subsea distribution unit and umbilical touch down point positions, the pipe connection topology and pipe routes. The practicality of this approach is demonstrated by designing a layout with one FPSO and 22 subsea control modules. The results indicate that the multi-layer star-tree layout structure has a lower total cost compared to that of the multi-layer star layout structure. In addition, the results were compared with a case that ignores the seabed terrain, indicating differences in the total construction cost. This method provides engineers with quantitative references and reliable cost estimates to make decisions regarding the layout of the subsea production control system.

Design and Performance Analysis for the Low-Power Holding Mechanism of the All-Electric Subsea Gate Valve Actuator

The all-electric subsea gate valve actuator is one of the critical components of the all-electric subsea production control system. To bridge the gap of the low-power holding mechanism in the all-electric subsea gate valve actuator of the subsea production system, minimize the power consumption and cable number for control and improve the open-position keeping performance of all-electric subsea gate valve actuator, this paper proposed a novel low-power holding mechanism for the all-electric subsea gate valve actuator which can be applied to all-electric subsea gate valve actuators with various valve sizes and process pressure ratings. The proposed low-power holding mechanism uses an electromagnet as a driving element, combines the spiral transmission and the cam-like transmission, and only requires a holding force of approximately 2–7% of the maximum load of the closing spring to keep the valve open. The proposed low-power holding mechanism converts the axial force of the closing spring into the circumferential force, which substantially reduces the output force required for the driving element of the low-power holding mechanism and the number of the actuator’s control cables. Analytic models are created for the lockable maximum load of the closing spring and the permissible stroke of the locking tab with regard to the design variables. The parameter effects and the corresponding sensitivities are discussed by numerical analysis. The design parameters and the lockable maximum load of the closing spring of the low-power holding mechanism are obtained.

Merits of all-electric subsea production control system

Recently, researches on all-electric subsea system have been in progress. This paper describes a subsea tree using a lot of electrical signal and subsea control system. The way of subsea control is classified as all-electric systems or electro hydraulic systems. One of that has more merits in terms of cost, weight, power consumption, etc. because it uses electric signal instead of hydraulic signal. This paper describes the difference of each system’s power consumption and simulation. As the result, if each system applies the same number of sensors, actuators, etc. The power consumption of all-electric system’s load is less than at least 400kWh/day compared to the electro hydraulic system load.

Supporting the verification of compliance to safety standards via model-driven engineering: Approach, tool-support and empirical validation

ContextMany safety–critical systems are subject to safety certification as a way to provide assurance that these systems cannot unduly harm people, property or the environment. Creating the requisite evidence for certification can be a challenging task due to the sheer size of the textual standards based on which certification is performed and the amenability of these standards to subjective interpretation. ObjectiveThis paper proposes a novel approach to aid suppliers in creating the evidence necessary for certification according to standards. The approach is based on Model-Driven Engineering (MDE) and addresses the challenges of using certification standards while providing assistance with compliance. MethodGiven a safety standard, a conceptual model is built that provides a succinct and explicit interpretation of the standard. This model is then used to create a UML profile that helps system suppliers in relating the concepts of the safety standard to those of the application domain, in turn enabling the suppliers to demonstrate how their system development artifacts comply with the standard. ResultsWe provide a generalizable and tool-supported solution to support the verification of compliance to safety standards. Empirical validation of the work is presented via an industrial case study that shows how the concepts of a sub-sea production control system can be aligned with the evidence requirements of the IEC61508 standard. A subsequent survey examines the perceptions of practitioners about the solution. ConclusionThe case study indicates that the supplier company where the study was performed found the approach useful in helping them prepare for certification of their software. The survey indicates that practitioners found our approach easy to understand and that they would be willing to adopt it in practice. Since the IEC61508 standard applies to multiple domains, these results suggest wider applicability and usefulness of our work.

All-Electric Subsea Production Control System

All-Electric Subsea Production Control System, which has many advantages over conventional Multiple Electric-hydraulic control system, is the development tendency of subsea production control system. Being based on principle of all-electric control system, its advantages, working principle and key technologies were analyzed in this paper, which could be a reference for further study.

Design of Hydraulic System of Subsea X-Tree

Onshore hydraulic systems are not generally applied in subsea production control system,so how to design a special needed hydraulic system for subsea X-tree has been one of the hot research questions.Several specific hydraulic components were analyzed, such as hydraulic power unite,umbilical,subsea control model,hydraulic control valve and valve actuator, and then corresponding hydraulic schematic which can meet the requirements of subsea X-tree is presented.

Benefits of All-Electric Subsea Production-Control Systems

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper OTC 17106, "Benefits of All-Electric Subsea Production-Control Systems," by M. Theobald and C. Lindsey-Curran, BP plc, prepared for the 2005 Offshore Technology Conference, Houston, 2-5 May. The oil and gas industry currently is using electrohydraulic subsea control systems as the standard to manage hydrocarbon production from subsea oil and gas fields. While these electrohydraulic controls will continue as the system of choice for the next 5 years, a desire to improve reliability and operational routines will increase the opportunity to use all-electric subsea production-control systems. The first offshore trial of an all-electric subsea production-control system and wellhead tree system was completed recently at the BP Magnus platform in the North Sea. Introduction To produce from greater water depths and harsher metocean conditions, the offshore industry has become technologically sophisticated. This applies both to the floating structures that support topside facilities in water depths greater than 200 m and the tieback technology to produce from long-distance remote step-out wells many tens of kilometers from the host facility. In the early days of subsea tiebacks, each of the hydraulic valves needed to control the flow of hydrocarbons from the wellhead systems was controlled individually by a direct hydraulic connection back to the host facility and a topside control panel. The panel consisted of hydraulic pumps, motors, valves, and accumulators. This was a very successful and reliable concept because of its simplicity and relatively low cost. However, the limitation of direct hydraulics resulted in slow subsea-to-host actuator response times, and this limited tieback distance to approximately 15 km. In addition, the size and weight of the connecting umbilical hoses in all but the simplest of systems resulted in difficulties with transportation and installation. These limitations, together with the increasing requirements to collect reservoir-pressure and -temperature data, prompted the industry to develop more-sophisticated technology, including subsea control systems.

Subsea Control and Data Acquisition

Optimising field performance: troll pilot control system - advanced control system for a subsea separator, C. Baggs et al implementation of control system for wells - an operator's view and experience, I. Polden smart controls - a subsea control system to smart field developments. Buoy-based systems: current experience and future applications for remote buoys, T. Pipe the universal buoy system (tubs), D. Bone, T. Cousins monitoring and control of marginal oilfields, M. Philips. Intervention: swimmer -subsea work, inspection, and maintenance with minimum environment ROV, P. Marty. Systems architecture and sensors: the development and testing of a downhole optical gauge system, J. Edwards what price reliability? P. Yates a new generation deepwater control system, J. Cattanach. Experience feedback: BP Amoco subsea control system lessons, R. Fleming corrosion control of subsea production control systems - 20 years of experience, T. Sydberger, T. Helgesen. Subsea communication: fibre optic technology for subsea control and monitoring systems, H. Nakstad cable-less remote monitoring (using a flowline as an electrical transmission line), G. Jones, S. Hudson acoustic BOP test tool, S. Jernov.

Corrosion Control of Subsea Production Control Systems: Twenty Years' Experience

Corrosion Control of Subsea Production Control Systems: Twenty Years' Experience

CONTROL SYSTEM FOR REMOTE SUBSEA COMPLETIONS

The Seahorse and Tarwhine subsea completions are among a number of recent developments in Bass Strait designed to exploit relatively small and remote fields. Both wells have been developed by re-entering and completing the original exploration wells and tying them back to the nearest existing platform, Barracouta, with an insulated production flowline, a gas lift supply line, and an electrohydraulic control umbilical. Seahorse is a little over 11 km north, and Tarwhine almost 18 km south-west of Barracouta, and it is these long offset distances which significantly influenced the decision to adopt an electrohydraulic control system. The advantages of an electrohydraulic system in this application, compared to the other control techniques available, are that it provides a faster response time to surface initiated commands, it has an overall lower cost, and it provides information back to the surface about conditions at the subsea well.Many of the components used in the subsea production control system are innovative and highly specialised, for example, the conductive electrical couplers and the temperature transducers. A significant amount of the equipment also has its origins in the aerospace industry and, like in that industry, demands a high commitment to quality assurance and quality control throughout the manufacturing and assembly phases of the project. Seahorse and Tarwhine have now been producing successfully since September and May 1990, respectively. The success of this project gives the joint venture partners, Esso and BHPP, confidence to use subsea technology to continue developing smaller fields, particularly as developments move into deeper water approaching and beyond the edge of the continental shelf.