Authors: Sui, Dan; Nybø, Roar; Hovland, Svein; Johansen, Tor Arne

Abstract: To ensure safe and stable drilling operation, bottomhole pressure(BHP) should be kept within some region. However measurement of the BHP is sometimes not available or reliable, especially when the circulation is low, e.g., during pipe connection procedures. This paper presents the application of a moving horizon estimation (MHE) method for online estimation of the BHP during petroleum drilling. In the proposed MHE formulation the states are estimated by a forward simulation with a pre-estimating observer. Moreover, it considers the constraints of states/outputs in the MHE problem. Application of the observer to a real data set from a North Sea oil well illustrates potential benefits.

Keywords: Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00024

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 145-150

Authors: Akhmetzyanov, Atlas; Ermolaev, Alexander; Grebennik, Oleg

Abstract: In this paper we consider problems of optimization and selection of development systems (technologies) of oil/gas fields, consisting of some disjoint oil/gas pools (in terms of hydrodynamics), tied by resource constraints or general oil/gas production plan. In order to solve these problems, formulated as MILP models, we have developed approximate algorithm using Lagrangian relaxation. Initially we consider the problem for oil fields and then for gas fields. Contrary to another models and techniques, used for solving the similar problems, our models and algorithms allow us to coordinate allocation of production volumes and reserves among the pools with selection of optimal development system, as well as optimization of technological parameters for each pool. We have also examined the perspective approaches, using both multilevel decomposition of oil reservoirs, and hierarchical splitting, and parallel computing on supercomputer for developing effective problem-solving procedures.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00028

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 151-156

Authors: Elgsæter, Steinar M.; Kittilsen, Pål; Hauger, Svein Olav

Abstract: Model-based online applications such as soft-sensing, fault detection or model predictive control require representative online models. Basing models on physics has the advantage of naturally describing nonlinear processes and potentially describing a wide range of operating conditions. Implementing adaptivity is essential for online use to avoid model performance degradation over time and to compensate for model imperfection. Requirements for identifiability and observability, numerical robustness and computational speed place an upper limit on model complexity. These considerations motivate the design of balanced-complexity physical models with adaptivity for online use. Techniques used in the design of balanced complexity models are given with examples from oshore oil and gas production. Despite potential benefits, the effort required to implement balanced-complexity models,particularly at large scales, may deter their use. This paper presents a Modelica-based approach to reduce implementation effort by interfacing exported Modelica models with application code by means of a generic interface. The suggested approach is demonstrated by parameter estimation for a subsea well-manifold-pipeline system.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system; Subsea Production

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00011

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 157-162

Authors: Trivedi, Japan; Nejadi, Siavash; Leung, Juliana

Abstract: The Ensemble Kalman Filter (EnKF) is a Monte-Carlo based technique for assisted history matching and real time updating of reservoir models. However, it often fails to detect facies boundaries and proportions as the facies distributions are non-Gaussian, while geologic data for reservoir modeling is usually insufficient. It is convenient to represent distinct facies with non-Gaussian categorical indicators; we implemented discrete cosine transform (DCT) to parameterize the facies indicators into coefficients of the retained cosine basis functions that are Gaussian. For highly complex and heterogeneous models, though observed data were matched, it failed to reproduce realistic facies distribution corresponding to reference variogram and facies proportion. In this paper we propose a new ensemble filtering method in-between of EnKF and PF, where EnKF as predictor combines the advantages of accurate large updates with small ensembles and corrector for non-Gaussian distributions followed by EnKF again for analysis step. Correction is performed by regenerating new realizations using a new pilot point method. The ensemble members that are more consistent with the early production history and the available geological information are considered as high weight particles and used for the applications. Combination of DCT-EnKF and regenerating new realizations using the new pilot point method demonstrates reasonable improvement and reduction of uncertainty in facies detection. Incorporating the new step in the procedure assists the filter to honor the reference distribution and experimental variogram during the history matching process and presents an important potential in improved characterization of complex reservoirs.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00023

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 163-170

Authors: Benetazzo, Flavia; Ippoliti, Gianluca; Longhi, Sauro; Raspa, Paolo

Abstract: This paper presents a Discrete-Time Variable-Structure Control (DTVSC) for the dynamic positioning system of a marine supply vessel. The DTVSC guarantees robustness with respect to disturbances and parametric variations. Two wave-filtering approaches are employed: the Extended Kalman filter (EKF) and the multi-rate Kalman filter (MREKF) . The proposed solution is compared with a PID-based control and a passive non-linear wave filter. The reported simulations show that the proposed solution produces better performances and it is robust in the presence of input disturbances and model uncertainties.

Keywords: Autonomous systems/robotics

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00041

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 171-176

Authors: Hassani, Vahid; Soerensen, Asgeir; Pascoal, Antonio M.

Abstract: This paper describes a procedure to design robust controllers for Dynamic Positioning (DP) of ships and offshore rigs subjected to the influence of sea waves, currents, and wind loads using H∞ and mixed-μ techniques. To this effect, practical assumptions are exploited in order to obtain a linear design model with parametric uncertainties describing the dynamics of the vessel. Appropriate frequency weighting functions are selected to capture the required performance specifications at the controller design phase. The proposed model and weighting functions are then used to design robust controllers. The problem of wave filtering is also addressed during the process of modeling and controller design. The key contribution of the paper is twofold: i) it affords system designers a new method to efficiently obtain linearized design models that fit naturally in the framework of H∞ control theory, and ii) it describes, in a systematic manner, the different steps involved in the controller design process. Part II in a companion paper contains the details of simulations and results of experimental model tests in a towing tank equipped with a hydraulic wave maker.

Keywords: Subsea Production; Autonomous systems/robotics; Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00042

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 177-182

Authors: Hassani, Vahid; Soerensen, Asgeir; Pascoal, Antonio M.

Abstract: This paper is a follow-up of a companion paper by Hassani et al. (2012b) on a control design methodology for Dynamic Positioning (DP) of marine vessels and offshore rigs subjected to the influence of sea waves, currents, and wind loads using mixed-μ synthesis. The present paper describes the results of a design exercise in which robust controllers were designed for a representative vessel. Its main focus is on the discussion of the results of numerical simulations and experimental model-testing of a set of robust DP controllers operating under different sea conditions: calm, moderate, high, and extreme seas. The robust DP controllers were first evaluated in a high fidelity nonlinear DP simulator, illustrating the efficiency of the design. To bridge the gap between theory and practice, the results were experimentally verified by model testing of a DP operated ship, the Cybership III, under different simulated sea conditions in a towing tank equipped with a hydraulic wave maker.

Keywords: Subsea Production; Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.; Autonomous systems/robotics

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00043

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 183-188

Authors: Van den Hof, Paul M.J.; Jansen, Jan Dirk; Heemink, Arnold

Abstract: The past ten years have seen an increasing application of systems and control theory to porous media flow. This involves in particular the use of optimization, parameter identification, and model reduction techniques in attempts to increase the amount of oil or gas that can be recovered from subsurface hydrocarbon reservoirs. Other applications involve the control of ground water flow for drinking water or pollution control, and the subsurface storage of CO2. The dynamic behavior of subsurface multi-phase porous media flow is typically simulated with large-scale nonlinear numerical models, containing up to millions of state variables and parameters. Moreover, a typical characteristic of these models is a very large uncertainty in the parameter values, reflecting the very large geological uncertainty of the subsurface. Traditionally they are primarily used for ’field development’, i.e. the engineering of well configurations and production strategies, but an emerging use is in the ’real-time’ optimization and control of oil production, known as ’closed-loop reservoir management (CLRM)’. In this paper we describe some recent contributions of our group to the use of systems and control theory for CLRM. This concerns sequential and multi-level production optimization, identifiability of model parameters, and ’control-relevant’ upscaling.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system; Subsea Production

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00047

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 189-200

Authors: Downton, Geoff

Abstract: To fully model every aspect of the process of drilling a borehole is still in the realms of research. Great strides are being made to develop high-fidelity models of well-defined domains such as the rig systems, drillstring, rock-bit interaction, fluid control systems and the Earth. Bringing all these models together in any unified manner and proposing a unified control solution to fully automate the whole process is still an exploratory venture. The uncertainty prevailing over the magnitude and spatiotemporal distribution of disturbances to be controlled or rejected by systems best described by non-linear partial differential equations rather than linear approximations, makes for a very challenging control problem. This uncertainty also raises interesting questions on how detailed the models need to be and how this might change our approach to modeling in the future. However technology is never static and certain developments are currently in play that will dramatically improve our capacity to model and control processes which are currently considered too complex to control.

Keywords: Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00054

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 201-210

Authors: Stamnes, Øyvind Nistad; Mjaavatten, Erlend; Falk, Kristin

Abstract: Dual gradient drilling (DGD) is a method for drilling deep water offshore wells safely, efficiently, and to a reduced cost. The dual gradient effect is enforced by using a heavy fluid fitting the drilling window, and a subsea pump to lift the returns up to the rig. Automatic control of this pump is fundamental to ensure a safe and efficient dual gradient drilling operation. In this paper we extend existing work on modelling for DGD in two ways. Firstly, we present a simplified model for operational scenarios where there are multiple fluids in the well, e.g. when changing drilling fluids. Secondly, we make the model more realistic by including a model of the centrifugal subsea pump. The resulting model is then used to simulate a scenario with changing of drilling fluid, and where a PI controller is used to maintain a constant downhole pressure. The simulation confirms that the model is reasonable, and that the PI controller is able to maintain a near constant downhole pressure throughout the operation.

Keywords: Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00010

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 211-216

Authors: Carlsen, Liv Almås; Nygaard, Gerhard; Time, Rune W.

Abstract: This paper introduces a method to enable automatic updates of the density, compressibility and frictional effects of the drilling fluid during a drilling operation. By placing pressure sensors along the circulation path from the mud pump to the connection to the drillstring, the fluid dynamics can be examined more thoroughly at various flow rates and pressures. This will help filling the gap of reliable data on drilling fluid properties, which is of great importance in automated drilling operations.

Keywords: Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00033

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 217-222

Authors: Reitsma, Donald; Couturier, Yawan

Abstract: Managed Pressure Drilling (MPD) is performed in offshore and onshore oil and gas areas to reduce the risks that may be associated with using conventional drilling hydraulic methods. The aim of MPD is to reliably and precisely control the pressure at the bottom of well within what is known as the ‘pressure window’. Manual control of the choke valve was adapted from manual well control methods developed for circulating out an oil or gas influx. There have also been attempts dating back more than 40 years to automate the choke controller for influx circulation, though as of today there is still not a reliable automated system available for this purpose. Over the last ten years, MPD systems with various levels of automation have been developed. The current automated MPD system has been successfully used worldwide to drill hundreds of wells with narrow pressure windows. This paper discusses the development history and the newest developments in automated choke control with a forward-looking view of automated processes to precisely manage well pressure.

Keywords: Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00049

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 223-230

Authors: Cayeux, Eric

Abstract: For complex drilling operations with narrow geo-pressure windows, it is not uncommon to have problems with formation fracturing, due to erroneous mud pump management. To assist the driller in managing the circulation, it is possible to limit both the acceleration of the mud pumps whilst changing the flow-rate as well as the actual flow-rate, to avoid generating downhole pressure above the fracturing pressure gradient of the open hole section. Such mud pump operating limits are dependent on the operational parameters (e.g. drill-string axial and rotational velocities), and the in situ conditions downhole. The in situ conditions evolve with time due to the changes of bit and bottom hole depths as well as the variations in temperature, mud properties and cutting concentrations. When starting to condition mud after a long period of time without circulation, the changes in temperature can be very large. Furthermore, in the eventuality of barite sag, lifting up drilling fluids containing a large concentration of high gravity solid can cause much increase of the downhole pressure. This paper presents a methodology that is used in an automatic drilling control system to account for all those factors in order to have a safe mud pump management including circumstances where mud is being conditioned.

Keywords: Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00018

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 231-238

Authors: Mahdianfar, Hessam; Aamo, Ole Morten; Pavlov, Alexey

Abstract: A model describing the flow and pressure fluctuations in the bore-hole due to drill-string movement has been presented. It consists of a pair of coupled nonlinear partial differential equations modelling the distributed pressure and flow in the well, and a superposition of multiple sine waves for the disturbance. Considering only top-side flow and pressure as measurements, it is shown that the model can be represented by a linear time invariant finite-dimensional system with output delay. This result is achieved by linearization and de-coupling using Riemann invariants. An infinite-dimensional observer is designed that estimates the disturbance, and the estimate is used in a controller that rejects the effect of the disturbance on the down-hole pressure. A model reduction technique based on the Laguerre series representation of the transfer function is used to derive a finite-dimensional, rational transfer function for the controller. The performance of the full-order and reduced-order controllers are compared in simulations, which show satisfactory attenuation of the heave disturbance for both controllers.

Keywords: Automated Drilling: Managed pressure drilling, Dualgradient systems, Directional drilling, etc.

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00013

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 239-244

Authors: Miyoshi, Simone; Zyngier, Danielle; Souza Jr., Maurício; Secchi, Argimiro R.; Teixeira, Alex; Campos, Mário; Lima, Enrique

Abstract: In this work a hybrid methodology based on statistical approach and phenomenological modeling was developed aiming the monitoring of the performance of compression equipment in an offshore oil platform. A rigorous model was employed in order to estimate thermodynamic based values of the performance of the compression system, given by the polytropic efficiency and head. Residuals were generated by comparing the model values with the ones which were calculated from manufacturer’s curves using process data (suction and discharge pressures and temperatures, turbine rotation and suction flow). Even though the monitoring technique developed is essentially multivariable and dynamic, the results are displayed using typical univariate process control charts, providing a friendly interface for the operator and allowing the clear detection of process faults.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00019

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 245-250

Authors: Cortinovis, Andrea; Pareschi, Diego; Mercangöz, Mehmet; Besselmann, Thomas

Abstract: In this article torque assisted anti-surge control (TASC), a compressor anti-surge control system based on model predictive control (MPC) is presented. TASC is implemented on an embedded system for the control of compressor stations with electrical variable-speed drives (VSD) which are used in applications such as natural gas transportation via pipelines. The manipulated variables of the proposed advanced controller are the electric motor torque and the position of a recycle valve, whereas the measured quantities are the same as those of a typical compressor control application including the pressure ratio and the gas flow. The TASC scheme uses the linear approximation of a nonlinear dynamic model to predict the behavior of the compression system. The information contained in the compressor map is incorporated into the nonlinear model as a 3rd order polynomial approximation. The surge line is taken into account as a constraint in the MPC formulation. Control action is calculated by solving an optimization problem in real-time at the control unit level with cycle times as low as 20 ms. The potential benefits of the proposed control strategy are evaluated in a simulation scenario corresponding to a potential deep surge event typically used in anti-surge control validation exercises. The simulations are carried out in a hardware-in-the-loop setting. In the evaluation, the performance of TASC is compared to a conventional anti-surge control approach. Due to the predictive capability and the manipulation of the motor torque, TASC is observed to achieve a safer and more efficient operation of the compressor station.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00052

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 251-256

Authors: Yang, Zhenyu; Soleiman, Kian; Løhndorf, Bo

Abstract: The energy efficient control of a pump system for an offshore oil processing system is investigated. The seawater is lifted up by a pump system which consists of three identical centrifugal pumps in parallel, and the lifted seawater is used to cool down the crude oil flowing out of a three-phase separator on one of the Danish north-sea platform. A hierarchical pump-speed control strategy is developed for the considered system by minimizing the pump power consumption subject to keeping a satisfactory system performance. The proposed control strategy consists of online estimation of some system operating parameters, optimization of pump configurations, and a real-time feedback control. Comparing with the current control strategy at the considered system, where the pump system is on/off controlled, and the seawater flows are controlled by a number of control valves, the proposed control strategy has showed significant energy savings without sacrificing the system performance.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00050

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 257-262

Authors: Uddin, Nur; Gravdahl, Jan Tommy

Abstract: A novel method for introducing a back-up system to an active compressor surge control system is presented in this paper. Active surge control is a promising method for extending the compressor map towards and into the unstable area at low mass flow by stabilizing the surge phenomenon. The method also has potential for allowing operation at higher efficiencies. However, a failure in the active surge control system may endanger the compressor by entering deep surge as the compressor is allowed to operate in the stabilized surge area. We propose the use of a back-up system applied to the active system to keep the compressor safe should the active system fail. This paper present an active compressor surge control system with piston actuation combined with a blow off system as the back-up. Performance of the combined system is evaluated by simulating the system in situations where the piston is saturated or jammed. The combination results in a system with increased performance by taking advantage of both systems.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00053

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 263-268

Authors: Boechat, Andre A.; Moreno, Ubirajara F.; Haramura, Decio, Jr.

Abstract: In the oilfield industry, data collected from well sensors plays an important role in performance and security applications. The quality of the measurements is directly related to the accuracy of the control actions and the optimisation of the production. On-line calibration monitoring systems can determine drifts in the sensors measurements and provide more reliable information to the user. In this paper, a robust on-line calibration monitoring system for drift correction/detection in well sensors is presented and evaluated for simulated and real data sets. Comparisons with a state-of-art monitoring system is also showed. The results indicate a promising applicability of the calibration monitoring system for the oilfield industry data.

Keywords: Smart Wells; Environmental and Safety Issues

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00037

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 269-274

Authors: Grimstad, Bjarne; Gunnerud, Vidar; Ljungquist, Dag; Ausen, Håvard; Lervik, Victoria

Abstract: In this paper we present an implementation of a partly Derivative-Free Optimization (DFO) algorithm for production optimization of a simulated multi-phase flow network. The network consists of well and pipeline simulators, considered to be black-box models without available gradients. The algorithm utilizes local approximations as surrogate models for the complex simulators. A Mixed Integer Nonlinear Programming (MINLP) problem is built from the surrogate models and the known structure of the flow network. The core of the algorithm is IBM's MINLP solver Bonmin, which is run iteratively to solve optimization problems cast in terms of surrogate models. At each iteration the surrogate models are updated to fit local data points from the simulators. The algorithm is tested on an artificial subsea network modeled in FlowManagerTM, a multi-phase flow simulator from FMC Technologies. The results for this special case show that the algorithm converges to a point where the surrogate models fit the simulator, and they both share the optimum.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system; Subsea Production

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00031

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 275-280

Authors: Akhmetzyanov, Atlas; Salnikov, Anton

Abstract: The need for solving the problem of identification of basic parameters (permeability coefficients, initial and boundary conditions) for hydrodynamic models of reservoirs on retrospective data arises from incompleteness and observational errors in source and current information about controlled object at all stages of reservoir engineering. Iterative methods for simultaneous solving of direct and inverse problems for original model equations on retrospective data are proposed to solve the problems of identification and adaptation of initial and boundary conditions and filtration parameters. Parallel computing technologies with optimal hierarchical (multilevel) embedding of algorithms into the architecture of supercomputers are offered for creation an integrated model of complex technological system.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00027

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 281-285

Authors: Capolei, Andrea; Völcker, Carsten; Frydendall, Jan; Jorgensen, John Bagterp

Abstract: Conventional recovery techniques enable recovery of 10-50% of the oil in an oil field. Advances in smart well technology and enhanced oil recovery techniques enable significant larger recovery. To realize this potential, feedback model-based optimal control technologies are needed to manipulate the injections and oil production such that flow is uniform in a given geological structure. Even in the case of conventional water flooding, feedback based optimal control technologies may enable higher oil recovery than with conventional operational strategies. The optimal control problems that must be solved are large-scale problems and require specialized numerical algorithms. In this paper, we combine a single shooting optimization algorithm based on sequential quadratic programming (SQP) with explicit singly diagonally implicit Runge-Kutta (ESDIRK) integration methods and the a continuous adjoint method for sensitivity computation. We demonstrate the procedure on a water flooding example with conventional injectors and producers.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system; Subsea Production; Smart Wells

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00030

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 286-291

Authors: Silva, Thiago L.; Codas, Andrés; Camponogara, Eduardo

Abstract: The lift-gas allocation problem with pressure-drop constraints and well-separator routing is a mixed-integer nonlinear program considerably hard to solve. To this end, a mixed-integer linear programming formulation was developed by multidimensional piecewise-linearization of pressure drop functions using standard (CC) and logarithmic (Log) aggregated models. These models were compared by means of a computational analysis, which indicates that the logarithmic model is faster than the standard one possibly because of the reduced number of variables and constraints.

Keywords: Production Optimisation: Coupling of production data and transmission systems with numerical modeling and optimization and decision support applications for the reservoir and production system

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00006

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 292-298

Authors: Kjelland, Magnus Berthelsen; Tyapin, Ilya; Hovland, Geir; Hansen, Michael Rygaard

Abstract: Abstract: In this paper, theoretical and experimental implementation of heave compensation on a redundant hydraulically actuated manipulator with 3-dof has been carried out. The redundancy is solved using the pseudo-inverse Jacobian method. Techniques for minimizing velocities and avoiding mechanical joint saturations is implemented in the null space joint motion. Model based feed-forward, combined with a PI-controller handles the velocity control of each joint.A time domain simulation model has been developed, experimentally veried, and used for controller parameter tuning. Model verication and experimental results are obtained while the manipulator is exposed to wave disturbances created in a dry environment by means of a Stewart platform.

Keywords: Autonomous systems/robotics

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00034

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 299-304

Authors: Fortaleza, Eugenio

Abstract: This article uses an active control dedicated to the positioning of subsea structures like flow lines. This kind of operation consists in connecting the bottom end of a very long pipeline to the wellhead, by dynamically modifying the pipeline top end position, which is linked to a Dynamically Positioned Vessel (DPV). Such long pipelines are usually called risers, because they are used to rise the drilling mud or the hydrocarbons from the wellhead to the platform. Nowadays this operation is often done manually. The use of an active control intends to reduce the operation time, and to make it possible even under bad weather conditions. The considered subsea structure can be aproximated as a cable submerged in a flow and modelled by the Bernoulli cable equation, completed with a damping factor, that linearly depends on the structure speed. This article tests previous works regarding the tracking system used to follow the reference trajectory of the motion planning considering the Euler-Bernoulli beam equation for large rotations, that is the most used model to define the dynamic behavior of this kind of structures.

Keywords: Autonomous systems/robotics; Subsea Production

Digital Object Identifier (DOI): 10.3182/20120531-2-NO-4020.00045

Conference: 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production

Location: Norwegian University of Science and Technology, Norway

Start Date: Thu May 31 2012 - End Date: Fri Jun 01 2012

Page Numbers: 305-309