New slug control strategies, tuning rules and experimental results

Godhavn, John–Morten; Fard, Mehrdad P.; Fuchs, Per H.

doi:10.1016/j.jprocont.2004.10.003

Cited by 97 publications

(47 citation statements)

References 1 publication

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“…The oscillatory flow condition in offshore multi-phase pipelines is undesirable and an effective solution is needed to suppress it [1]. Active control of the topside choke valve is a recommended solution to maintain a non-oscillatory flow regime together with the maximum possible production rate [2], and the control system used for this purpose is called anti-slug control.…”

Section: Introductionmentioning

confidence: 99%

Anti-slug control experiments using nonlinear observers

Jahanshahi

Skogestad

Grøtli

2013

2013 American Control Conference

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Abstract-To prevent slug-flow on offshore oil production units, controlling a subsea pressure is the recommended solution. However, the subsea pressure is not often available as a measurement. The top-side pressure is usually measured but it is difficult to use for stabilizing control, because of its Right Half-Plane zero dynamics combined with nonlinearity. We have used the top-side pressure as measurement for different observers to estimate state variables of the system, and then used the estimated states for control. This scheme was tested in experiments using three types of observers. A simple Luenberger observer with a large gain was found to be more robust than the standard Unscented Kalman Filter (UKF). We modified the UKF to a Fast UKF for time-scale separation of the closed-loop system. The resulting observer was robust, also less sensitive to measurement noise compared to the simple Luenberger observer when measuring the top-side pressure. Surprisingly, the nonlinear observers were not able to work in closed-loop when the subsea pressure was used as the measurement. On the other hand, a linear observer worked very well for this case with a larger operating range compared to that of the top-side pressure.

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Section: Introductionmentioning

confidence: 99%

Anti-slug control experiments using nonlinear observers

Jahanshahi

Skogestad

Grøtli

2013

2013 American Control Conference

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“…8. Cascade control using measurements P 2 and F w have proved theoretically that this works for another case of riser slugging and it has also been shown that it is possible to stabilize the flow this way on larger test facilities (Godhavn et al, 2005b). However, so far we have not been able to verify this experimentally with the Miniloop.…”

Section: Cascade Controllermentioning

confidence: 97%

Cascade Control Experiments of Riser Slug Flow Using Topside Measurements

Sivertsen

Skogestad

2005

IFAC Proceedings Volumes

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Anti-slug control applied to two-phase flow provides a very challenging and important application for feedback control. It is important because it allows for operation that would otherwise be impossible, and challenging because of the presence of both RHP-poles and RHP-zeros.To conduct experiments on pipeline-riser anti-slug control, a small-scale slug-loop has been build. The loop has been modelled and analyzed using the simplified riser-slug model by Storkaas. The aim has been to find ways to control the flow using only topside measurements, as subsea measurements can be unavailable offshore. The results from this analysis and experimental results using a cascade controller are presented in this paper.

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“…• Cascade control strategies of a well-subsea-riser, controlling riser base pressure with topside-and subsea choke, in Godhavn et al (2005) In this paper we will not use any models developed from mechanistic rules, actually, since the controlling results presented in this paper evolve only from a collection of data we may refer to this solution as ModelFree Control (MFC), a concept contained in Di Ruscio (2012). The previous mentioned paper demonstrates MFC on a lab-scale quadruple tank process using an LQR optimal controller.…”

Section: Introductionmentioning

confidence: 99%

Model-free optimal anti-slug control of a well-pipeline-riser in the K-Spice/LedaFlow simulator

Dalen¹,

Ruscio²,

Nilsen³

2015

MIC

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Simplified models are developed for a 3-phase well-pipeline-riser and tested together with a high fidelity dynamic model built in K-Spice and LedaFlow. These models are developed from a subspace algorithm, i.e. Deterministic and Stochastic system identification and Realization (DSR), and implemented in a Linear Quadratic optimal Regulator (LQR) for stabilizing the slugging regime. We are comparing LQR with PI controller using different performance measures.

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New slug control strategies, tuning rules and experimental results

Cited by 97 publications

References 1 publication

Anti-slug control experiments using nonlinear observers

Anti-slug control experiments using nonlinear observers

Cascade Control Experiments of Riser Slug Flow Using Topside Measurements

Model-free optimal anti-slug control of a well-pipeline-riser in the K-Spice/LedaFlow simulator

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