Computational Simulation of the Drilling Vessel Motion and its Effects on the Riser/BOP Connection

2019 ◽  
Author(s):  
Xavier Castello ◽  
José Luis Párraga Quispe ◽  
Segen F. Estefen ◽  
Marcelo Igor Lourenço de Souza ◽  
Nilo de Moura Jorge
Keyword(s):  
Computational Simulation ◽  
Horizontal Displacement ◽  
Environmental Damage ◽  
Marine Riser ◽  
Offshore Drilling ◽  
Propagating Waves ◽  
Drilling Operations ◽  
Heave Motion ◽  
Vessel Motion ◽  
Typical Scenario

Abstract During subsea offshore drilling operations, the floating vessel is connected to the wellhead through a series of equipment assemblies. The riser is exposed to dynamic loads from currents, waves, and drilling platform motions. Therefore, a dynamic analysis of the riser system is required to obtain forces and moments in the wellhead. It is even more important in dynamic positioning (DP) operations, where the knowledge of boundary conditions for a safe emergency disconnection is highly relevant. The objective of this paper is to calculate the effects of changing the light and older BOP (typically with 4 rams) for newer and heavier BOPs (after Macondo accident, with 6 rams) on the Emergency Disconnect Sequence (EDS) time and on wellhead equipment strength. A typical scenario of drilling is proposed, in which the marine riser system considers the drilling string, the lower flex-joint, the marine riser, the kill and choke lines and the tensioners. Tensioners are used to top tension the marine riser and to compensate relative heave motion between the riser and the floating vessel. Riser systems were designed using the API RP 16Q and simulated using Orcaflex software. Vessel dynamic motions were calculated according to the response amplitude operator (RAO) data from a typical offshore drilling semi-submersible. The vessel motion is superimposed by a drift-off motion, which consists of a horizontal displacement along time in the direction of the propagating waves. It is employed to simulate the condition of vessel position loss due to thruster and or control system failure. Results indicate that the use of heavier BOPs reduces significantly the available time for initiating the EDS. Results are worse if older generation of wellhead equipment is used, where a smaller drift-off is necessary to safely disconnect the riser before potential equipment and environmental damage occurs.

Arctic Offshore Engineering—An Overview

1983 ◽  
Vol 20 (04) ◽  
pp. 323-331
Author(s):  
Peter G. Noble
Keyword(s):  
Oil And Gas ◽  
State Of The Art ◽  
Canadian Arctic ◽  
Marine Riser ◽  
Offshore Drilling ◽  
Engineering Technology ◽  
Offshore Engineering ◽  
New Concepts ◽  
Drilling Operations ◽  
Ice Forces

The paper examines the state of the art of offshore drilling operations in the ice-infested Beaufort Sea region of the Canadian Arctic. As exploration and drilling proceed farther and farther from the shoreline into deeper and more hostile waters, new concepts are evolving in Arctic engineering technology to permit the economical recovery of vast resources of oil and gas over an extended season. Several of these innovations, including a deep-hulled drillship designed to protect the marine riser and reduce ice forces, artificial islands of the caisson type, and the use of massive icebreaking dredges, are described and illustrated.

Effect of waste rock inclusions on the seismic stability of an upstream raised tailings impoundment: a numerical investigation

2015 ◽  
Vol 52 (12) ◽  
pp. 1930-1944 ◽  
Author(s):  
Behnam Ferdosi ◽  
Michael James ◽  
Michel Aubertin
Keyword(s):  
Ground Motions ◽  
Low Frequency ◽  
Horizontal Displacement ◽  
Waste Rock ◽  
Seismic Stability ◽  
Environmental Damage ◽  
Total Width ◽  
Tailings Impoundment ◽  
Downstream Slope ◽  
Potential Failure

Over the years, seismic activity has been a relatively common cause of tailings impoundment failure. The flow of liquefied tailings from such ruptures can result in very severe consequences, including loss of life and environmental damage. A co-disposal technique consisting of placing waste rock inclusions in tailings impoundments prior to and during tailings deposition was proposed by the authors. The waste rock is placed to create continuous inclusions within the impoundment, which provide a number of environmental and geotechnical benefits, particularly with respect to seismic stability. The results of numerical simulations previously performed have shown that the UBCSAND model can predict the seismic response of tailings. The UBCSAND constitutive model was used to conduct simulations to evaluate of the use of waste rock inclusions to improve the seismic stability of a tailings impoundment. The evaluation consists of numerical analyses of an actual tailings impoundment as constructed (without inclusions), and then assuming that it was constructed with inclusions, subjected to earthquake loads of various energy contents and with different predominant frequencies. The analyses were conducted in static, seismic, and post-shaking phases. The displacement of the surface of downstream slope of the tailings dyke was recorded during the analyses. The results indicate that the presence of waste rock inclusions can significantly improve the seismic behavior of the impoundment by reducing the displacements of the surface of the downstream slope and the extent of potential failure zones. Also, the results show that in most cases, the influence of a low-frequency earthquake on the displacement of the downstream slope of the tailings dyke is more important than that of a high-frequency earthquake. The performances of the tailings impoundment with different configurations of waste rock inclusions (varying width and center-to-center spacing) were classified based on the average normalized horizontal displacement of the downstream slope (ARx) for a range input ground motions. Charts were then developed to show how ARx is influenced by the total width of inclusions, their spacing, and the input ground motions.

A Study on the Main Parameters That Affects the Reliability of Fatigue Failure in a Marine Drilling Riser

2021 ◽  
Author(s):  
Bruno Luiz Barbosa das Chagas ◽  
Celso Kazuyuki Morooka
Keyword(s):  
Fatigue Damage ◽  
Fatigue Failure ◽  
Petroleum Reservoirs ◽  
Offshore Drilling ◽  
Deepwater Drilling ◽  
Sea Bottom ◽  
Reliability Method ◽  
Drilling Operations ◽  
Maritime Operations ◽  
Sea Currents

Abstract Advances in subsea exploration in the oceans to discover new petroleum reservoirs and sometimes different kind of minerals at the seabed in ultra deepwater, continuously introduce new challenges in offshore drilling operations. This motivates the development of increasingly safe maritime operations. In offshore petroleum, a marine drilling riser is the pipe that connects a wellhead at the sea bottom to a drillship at the sea surface, as an access to the wellbore. It serves as a guide for the drilling column with the drill bit and conductor to carry cuttings of rock coming from the wellbore drilling and its construction. Drilling riser is constantly exposed to adversity from the environment, such as waves, sea currents and platform motions induced by waves. These elements of the environment are prevailing factors that can cause a riser failure during deepwater drilling operations with undesirable consequences for the environment. In the present work, key parameters that influence the probability of fatigue failure in a marine drilling riser are identified, and a parametric evaluation with those parameters are carried out. Dynamic behavior of a riser is previously calculated and fatigue damage is estimated. Afterwards, the First Order Reliability Method (FORM) is applied to determine the probability of fatigue failure on the riser. Fundamentals of the procedure are described, and results are illustrated through the analysis for a typical riser in deepwater drilling operation. Parametric evaluations are done observing points considered as critical along the riser length, and looking to the sensitivity of key parameters in the process. For this study, the SN curve from API guidelines is applied and accumulated fatigue damage is estimated from simulations of the stress time series and applying the Palmgren-Miner’s rule. Finally, the influence of each parameter in the reliability of fatigue failure is verified and discussions given.

scholarly journals Speciation and ultra trace determination of mercury in produced waters from offshore drilling operations using portable instrumentation and matrix-matching calibration

2019 ◽  
Vol 146 ◽  
pp. 1072-1082 ◽  
Author(s):  
Jarol R. Miranda-Andrades ◽  
Sarzamin Khan ◽  
Carlos A.T. Toloza ◽  
Roberta M. Maciel ◽  
Rainério Escalfoni ◽  
...  
Keyword(s):  
Trace Determination ◽  
Offshore Drilling ◽  
Portable Instrumentation ◽  
Drilling Operations ◽  
Produced Waters ◽  
Ultra Trace

Hydrodynamic Forces on a Marine Riser: A Velocity-Potential Method

1982 ◽  
Vol 104 (1) ◽  
pp. 53-57 ◽  
Author(s):  
J. S. Chung
Keyword(s):  
Free Surface ◽  
Velocity Potential ◽  
Potential Method ◽  
Hydrodynamic Forces ◽  
Marine Riser ◽  
Morison Equation ◽  
Wave Damping ◽  
Drag Forces ◽  
Vessel Motion ◽  
Semi Empirical

A linear equation is mathematically derived for hydrodynamic forces on a marine riser under effects of free surface and floating-vessel motion using a velocity-potential method. It accounts for inertia and wave damping forces, including the force caused by riser motion, and empirically includes the drag force caused by viscosity. The equation, when reduced to a simpler form, is basically identical to the semi-empirical Morison equation for the inertia and drag forces. Theoretical validity of the simpler equation and the Morison equation is discussed. Previously, practical, semi-empirical force equations on the riser have been suggested, ignoring the effects of the free surface and the wave damping. The equations in current practice are compared with the present simpler equation.

Mechanical Property Analysis of Materials and Application of Buttress Thread Buckle Marine Conductor

2011 ◽  
Vol 233-235 ◽  
pp. 2043-2046
Author(s):  
Zhong Li ◽  
Lai Bin Zhang ◽  
Fan Luo ◽  
Bai Ling Zhang ◽  
Shu Ying Tan
Keyword(s):  
Electrical Resistance ◽  
Simulation Analysis ◽  
Offshore Drilling ◽  
Mechanical Experiment ◽  
Drilling Operations ◽  
Drilling Cost ◽  
Design Requirements ◽  
Resistance Weld ◽  
Offshore Oil ◽  
Working Efficiency

At present, offshore drilling operations often use buttress thread casing as surface casing. The design conception of buttress thread casing comes from the offshore drilling’s demands and this kind of casing is mainly used as surface casing. This paper has taken material mechanical experiment, numerical simulation analysis and field test, the research results show that the various parameters of buttress thread casing fully complies with the drilling design requirements and the offshore oilfield production demands. This product can reduce drilling cost effectively, improve working efficiency and safety, and realize manufacture domestically. Meanwhile, the development of this project will fill the blank of the ERW (Electrical Resistance Weld) casing in CNOOC (China National Offshore Oil Corporation), and have a broad prospect of application.

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