The Experts below are selected from a list of 8532 Experts worldwide ranked by ideXlab platform
Harry Verhoeven - One of the best experts on this subject based on the ideXlab platform.
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effect of dgps failures on dynamic positioning of mobile Drilling units in the north sea
Accident Analysis & Prevention, 2009Co-Authors: Haibo Chen, Torgeir Moan, Harry VerhoevenAbstract:Basic features of differential global positioning system (DGPS), and its operational configuration on dynamically positioned (DP) mobile Offshore Drilling units in the North Sea are described. Generic failure modes of DGPS are discussed, and a critical DGPS failure which has the potential to cause drive-off for mobile Drilling units is identified. It is the simultaneous erroneous position data from two DGPS's. Barrier method is used to analyze this critical DGPS failure. Barrier elements to prevent this failure are identified. Deficiencies of each barrier element are revealed based on the incidents and operational experiences in the North Sea. Recommendations to strengthen these barrier elements, i.e. to prevent erroneous position data from DGPS, are proposed. These recommendations contribute to the safety of DP operations of mobile Offshore Drilling units.
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safety of dynamic positioning operations on mobile Offshore Drilling units
Reliability Engineering & System Safety, 2008Co-Authors: Haibo Chen, Torgeir Moan, Harry VerhoevenAbstract:Dynamic positioning of mobile Offshore Drilling units for Drilling operation (termed as DP Drilling operation) is analyzed in this paper. A safety modeling approach based on the barrier concept is developed. Safety of DP Drilling operation is modeled in terms of three main barrier functions, i.e. barrier functions to prevent loss of position, to arrest vessel movement and to prevent loss of well integrity, respectively. Analyses of each barrier function are performed. The associated barrier elements are identified, their existing deficiencies are revealed based on operational experience on the Norwegian Continental Shelf (NCS), and recommendations to strengthen each barrier element are proposed. These recommendations could improve safety of DP Drilling operation on the NCS. They are also valid to DP Drilling operations worldwide.
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safety of dynamic positioning operation on mobile Offshore Drilling units
ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering, 2004Co-Authors: Haibo Chen, Torgeir Moan, Harry VerhoevenAbstract:Safety of dynamic positioning operation on mobile Offshore Drilling units is characterized by two key parameters, namely, the resistance to loss of position, and the robustness of recovery. Both parameters should be evaluated in order to identify effective ways to further improve the safety. The failure modes, applicable frequencies, and probabilistic modeling for both loss of position and recovery are discussed in this paper. Influencing factors to the resistance and robustness parameters are identified respectively. The results contribute to the further development of the safety assessment methodology for DP operation on Drilling units. Areas that need further development of modeling approach and analyses are pointed out.Copyright © 2004 by ASME
Alexey Pavlov - One of the best experts on this subject based on the ideXlab platform.
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suppressing pressure oscillations in Offshore Drilling control design and experimental results
IEEE Transactions on Control Systems and Technology, 2015Co-Authors: Anders Albert, Ole Morten Aamo, Johnmorten Godhavn, Alexey PavlovAbstract:As oil exploration and development costs rise, the oil industry increases its efforts to improve oil recovery (IOR) from existing fields. IOR is achieved mainly by Drilling more wells, but Drilling in partially depleted reservoirs is challenging due to narrow pressure margins. Offshore Drilling in harsh environments, such as the North Sea, presents additional challenges, since the heaving motion from a floating rig induces large surge and swab pressures in the well. This brief suggests a remedy for this problem using automatic control of well pressure. Taking advantage of an experimental lab facility recently completed at NTNU, a model of the Drilling system is developed using subspace identification methods. The model serves as a basis for state estimation and controller design using model predictive control. Applying the controller to the lab facility, pressure oscillations are suppressed by 70%–90% compared with the open-loop case, depending on the period of the heave motion.
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attenuation of heave induced pressure oscillations in Offshore Drilling systems
Advances in Computing and Communications, 2012Co-Authors: Hessam Mahdianfar, Ole Morten Aamo, Alexey PavlovAbstract: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 simple oscillator 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 Rie-mann 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 simple, 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.
Jan Erik Vinnem - One of the best experts on this subject based on the ideXlab platform.
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quantitative risk analysis of oil and gas Drilling using deepwater horizon as case study
Reliability Engineering & System Safety, 2012Co-Authors: Jon Espen Skogdalen, Jan Erik VinnemAbstract:According to the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, the Macondo blowout requires a reassessment of the risks associated with Offshore Drilling. The Commission recommends a proactive, risk-based performance approach specific to individual facilities, operations and environments, similar to the safety case/Quantitative Risk Analysis (QRA) approach in the North Sea. A review of a 15 QRAs from the North Sea reveals that the analyses to a large extent only to calculate the frequency of blowout based on the number of Drilling operations. None of the reviewed analyses were initiated based on Risk Influence Factors (RIFs) uncovered in the conceptual phase of well planning. The QRAs do not include Human and Organisational Factors (HOFs). As seen in the Macondo blowout, most of the findings were related to HOFs, e.g. working practice, competence, communication, procedures and management. The narrow Drilling window related to deepwater Drilling has to be controlled by safety barriers that are dependent on HOFs. There is some research relating to the incorporation of HOFs in QRAs. Further improvements in methodology and datasets are necessary to ensure that the QRAs are valid for the individual facilities, operations and environments.
Haibo Chen - One of the best experts on this subject based on the ideXlab platform.
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effect of dgps failures on dynamic positioning of mobile Drilling units in the north sea
Accident Analysis & Prevention, 2009Co-Authors: Haibo Chen, Torgeir Moan, Harry VerhoevenAbstract:Basic features of differential global positioning system (DGPS), and its operational configuration on dynamically positioned (DP) mobile Offshore Drilling units in the North Sea are described. Generic failure modes of DGPS are discussed, and a critical DGPS failure which has the potential to cause drive-off for mobile Drilling units is identified. It is the simultaneous erroneous position data from two DGPS's. Barrier method is used to analyze this critical DGPS failure. Barrier elements to prevent this failure are identified. Deficiencies of each barrier element are revealed based on the incidents and operational experiences in the North Sea. Recommendations to strengthen these barrier elements, i.e. to prevent erroneous position data from DGPS, are proposed. These recommendations contribute to the safety of DP operations of mobile Offshore Drilling units.
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safety of dynamic positioning operations on mobile Offshore Drilling units
Reliability Engineering & System Safety, 2008Co-Authors: Haibo Chen, Torgeir Moan, Harry VerhoevenAbstract:Dynamic positioning of mobile Offshore Drilling units for Drilling operation (termed as DP Drilling operation) is analyzed in this paper. A safety modeling approach based on the barrier concept is developed. Safety of DP Drilling operation is modeled in terms of three main barrier functions, i.e. barrier functions to prevent loss of position, to arrest vessel movement and to prevent loss of well integrity, respectively. Analyses of each barrier function are performed. The associated barrier elements are identified, their existing deficiencies are revealed based on operational experience on the Norwegian Continental Shelf (NCS), and recommendations to strengthen each barrier element are proposed. These recommendations could improve safety of DP Drilling operation on the NCS. They are also valid to DP Drilling operations worldwide.
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safety of dynamic positioning operation on mobile Offshore Drilling units
ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering, 2004Co-Authors: Haibo Chen, Torgeir Moan, Harry VerhoevenAbstract:Safety of dynamic positioning operation on mobile Offshore Drilling units is characterized by two key parameters, namely, the resistance to loss of position, and the robustness of recovery. Both parameters should be evaluated in order to identify effective ways to further improve the safety. The failure modes, applicable frequencies, and probabilistic modeling for both loss of position and recovery are discussed in this paper. Influencing factors to the resistance and robustness parameters are identified respectively. The results contribute to the further development of the safety assessment methodology for DP operation on Drilling units. Areas that need further development of modeling approach and analyses are pointed out.Copyright © 2004 by ASME
Bente E. Moen - One of the best experts on this subject based on the ideXlab platform.
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Modeling of Oil Mist and Oil Vapor Concentration in the Shale Shaker Area on Offshore Drilling Installations
Journal of Occupational and Environmental Hygiene, 2009Co-Authors: Magne Bråtveit, Kjersti Steinsvåg, Stein Atle Lie, Bente E. MoenAbstract:The objective of this study was to develop regression models to predict concentrations of oil mist and oil vapor in the workplace atmosphere in the shale shaker area of Offshore Drilling installations. Collection of monitoring reports of oil mist and oil vapor in the mud handling areas of Offshore Drilling installations was done during visits to eight oil companies and five Drilling contractors. A questionnaire was sent to the rig owners requesting information about technical design of the shaker area. Linear mixed-effects models were developed using concentration of oil mist or oil vapor measured by stationary sampling as dependent variables, Drilling installation as random effect, and potential determinants related to process technical parameters and technical design of the shale shaker area as fixed effects. The dataset comprised stationary measurements of oil mist (n = 464) and oil vapor (n = 462) from the period 1998 to 2004. The arithmetic mean concentrations of oil mist and oil vapor were 3.89 mg/m...
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exposure to oil mist and oil vapour during Offshore Drilling in norway 1979 2004
Annals of Occupational Hygiene, 2006Co-Authors: Kjersti Steinsvåg, Magne Bråtveit, Bente E. MoenAbstract:Objectives: To describe personal exposure to airborne hydrocarbon contaminants (oil mist and oil vapour) from 1979 to 2004 in the mud-handling areas of Offshore Drilling facilities operating on the Norwegian continental shelf when Drilling with oil-based muds. Methods: Qualitative and quantitative information was gathered during visits to companies involved in Offshore oil and gas production in Norway. Monitoring reports on oil mist and oil vapour exposure covered 37 Drilling facilities. Exposure data were analysed using descriptive statistics and by constructing linear mixed-effects models. Results: Samples had been taken during the use of three generations of hydrocarbon base oils, namely diesel oils (1979–1984), low-aromatic mineral oils (1985–1997) and non-aromatic mineral oils (1998–2004). Sampling done before 1984 showed high exposure to diesel vapour (arithmetic mean, AM = 1217 mg m 3 ). When low-aromatic mineral oils were used, the exposure to oil mist and oil vapour was 4.3 and 36 mg m 3 , and the respective AMs for non-aromatic mineral oils were reduced to 0.54 and 16 mg m 3 . Downward time trends were indicated for both oil mist (6% per year) and oil vapour (8% per year) when the year of monitoring was introduced as a fixed effect in a linear mixed-effects model analysis. Rig type, technical control measures and mud temperature significantly determined exposure to oil mist. Rig type, type of base oil, viscosity of the base oil, work area, mud temperature and season significantly determined exposure to oil vapour. Major decreases in variability were found for the between-rig components. Conclusions: Exposure to oil mist and oil vapour declined over time in the mud-handling areas of Offshore Drilling facilities. Exposure levels were associated with rig type, mud temperature, technical control measures, base oil, viscosity of the base oil, work area and season.
