Subsea Compact Separation: Control System Design

Li, Z.; Olson, Michael; Rayachoti, V.; Gupte, P.; Pierre, Fritz; Gul, K.

doi:10.4043/25299-ms

Cited by 6 publications

(3 citation statements)

References 3 publications

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“…Although the pipe separator used in this study is different from those used in [7][8][9][10][11], it is the authors' belief that the results are transferable and that the results presented here can serve as a basis for future control design of pipe separators.…”

Section: Introductionmentioning

confidence: 92%

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Controller Design and Control Structure Analysis for a Novel Oil–Water Multi-Pipe Separator

et al. 2019

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To enable more efficient production of hydrocarbons on the seabed in waters where traditional separator equipment is infeasible, the offshore oil and gas industry is leaning towards more compact separation equipment. A novel multi-pipe separator concept, designed to meet the challenges of subsea separation, has been developed at the Department of Geoscience and Petroleum at the Norwegian University of Science and Technology. In this initial study, a control structure analysis for the novel separator concept, based on step-response experiments, is presented. Proportional-integral controllers and model reference adaptive controllers are designed for the different control loops. The proportional-integral controllers are tuned based on the well-established simple internal model control tuning rules. Both control methods are implemented and tested on a prototype of the separator concept. Different measurements are controlled, and results show that the performance of the separator under varying inlet conditions can be improved with proper selection of control inputs and measurements.

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Section: Introductionmentioning

confidence: 92%

“…The same is true for the work presented in [8]. Here, PID controllers, tuned by trial and error, was used to achieve the desired performance.…”

Section: Introductionmentioning

confidence: 99%

Controller Design and Control Structure Analysis for a Novel Oil–Water Multi-Pipe Separator

et al. 2019

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“…As of today, subsea separation is used on several projects [1] with water depths in the range of 210 m to 2438 m. Primary use of separation technology has been for gas-liquid separation. This type of solution can enable transportation of main liquids and gas separately thus reduce hydrate formation risks.…”

Section: Subsea Boosting and Flow Assurancementioning

confidence: 99%

Flow Assurance as a Show Stopper for Subsea Factory - Use of Subsea Separation for Mitigation and Elimination of Risks

Tienhaara

2015

Day 2 Wed, October 28, 2015

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Field developments, from greenfield to mature field rejuvenation are challenging and there are various possible options. Attention to production risks and flow assurance issues are key in determining what type of production concept that is optimal for any field in question.Sand production issues can have a severe impact on any field architecture but this can be remediated by the use of sand removal technologies. With the advances in separation technology and the feasibility of using subsea separation solutions, there can be many benefits in terms of reducing erosion and clogging risks as well as enabling prevention of gas hydrates. Subsea separation can be an important enabler for field development decisions.Some key technologies for subsea separation solutions, such as gas/liquid separators, desanders and hydrocyclones have been qualified for subsea applications and have been proven topsides. Gas/Liquid separation can be part of subsea solutions aimed to minimize formation risks of gas hydrate in the risers. Ongoing development work can contribute to reduce complexity and total project costs for field developments.Adequate technology qualification for new technology should be done utilizing a large-scale realistic conditions flow loop.

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Performance Testing of a Two-stage Produced Water De-oiling System for Subsea Applications

Gul

Grave

Wingaarden³

et al. 2014

SPE Annual Technical Conference and Exhibition

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ExxonMobil Upstream Research Company (EMURC) conducted a comprehensive laboratory testing program of a produced water de-oiling system primarily targeted for subsea applications. The test program included performance evaluation as well as durability testing of a two-stage mixed-flow de-oiling hydrocyclone technology. The objectives of the test program were to evaluate the separation performance of two system configurations i.e. decoupled and integrated hydrocyclones stages, to understand the overall system integration effects on the performance, and to determine system sustainability to sand loading. Subsea produced water treatment in deeper water applications requires robust, reliable and compact separation equipment. The performance testing confirmed the feasibility of a multi-stage mixed-flow hydrocyclone system for subsea applications and demonstrated that, within a given operating envelope, the system can treat challenging produced water streams with high oil-in-water (OIW) content of up to 5%, reducing it to a few hundred ppm level. In addition, the issue of turndown can be addressed by designing the de-oiling system with multiple parallel banks of liners. The de-oiling system testing was conducted with light and heavy crude oils, of gravities of 36 °API and 19 °API respectively, to map performance characteristics of a two-stage system with the first hydrocyclone stage of bulk oil removal and the second stage of water polishing. Variations in test conditions such as the flow rate, temperature, inlet oil concentration and the reject ratios were introduced to establish optimal operating ranges for each stage as well as for the system. The performance of the decoupled and the integrated system was evaluated by determining separation efficiency break-points at different operating conditions. Accelerated sand erosion tests were performed on a dedicated sand erosion test loop to evaluate different erosion resistant coatings for hydrocyclone liners. The erosion tests helped identify a promising coating solution that can withstand continuous sand loads for long-term operations. The test program demonstrated that a two-stage mixed-flow hydrocyclone de-oiling system can meet challenging subsea produced water treatment and reinjection requirements over a wide range of operating conditions. The paper presents the key results of the overall performance tests as well as the results of sand erosion testing of the hydrocylone liners with different coatings.

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Subsea Compact Separation: Control System Design

Cited by 6 publications

References 3 publications

Controller Design and Control Structure Analysis for a Novel Oil–Water Multi-Pipe Separator

Controller Design and Control Structure Analysis for a Novel Oil–Water Multi-Pipe Separator

Flow Assurance as a Show Stopper for Subsea Factory - Use of Subsea Separation for Mitigation and Elimination of Risks

Performance Testing of a Two-stage Produced Water De-oiling System for Subsea Applications

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