Arctic Offshore Engineering—An Overview

1983 ◽  
Vol 20 (04) ◽  
pp. 323-331
Author(s):  
Peter G. Noble

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.

Author(s):  
V.N. Melikhov ◽  
N.A. Krylov ◽  
I.V. Shevchenko ◽  
V.L. Shuster

Regarding the South Caspian oil and gas province, it is concluded that the Pliocene productivity prevails in the western part of the province, and that the gas and oil prospects of the eastern land side in the Mesozoic are prioritized. A retrospective analytical review of geological and geophysical data and publications on the Mesozoic of Southwestern Turkmenistan was carried out, which showed the low efficiency of the performed seismic and drilling operations in the exploration and evaluation of very complex Mesozoic objects. A massive resumption of state-of-the-art seismic exploration and appraisal drilling in priority areas and facilities performed by leading Russian companies is proposed. For some areas, a new, increased estimate of the projected gas resources is given. An example of modern high-efficiency additional exploration of the East Cheleken, a small Pliocene gas and oil field, which turned this field into a large one in terms of reserves, is given.


Author(s):  
Xavier Castello ◽  
José Luis Párraga Quispe ◽  
Segen F. Estefen ◽  
Marcelo Igor Lourenço de Souza ◽  
Nilo de Moura Jorge

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.


SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Zhi Zhang ◽  
Baojiang Sun ◽  
Zhiyuan Wang ◽  
Shikun Tong ◽  
Bing Guo ◽  
...  

Summary Offshore oil and gas has effectively alleviated the global shortage of oil and gas resources, and drilling operations are becoming increasingly frequent. However, the cuttings discharged during surface drilling are transported and deposited to form cuttings piles, which pose a serious threat to the marine ecological environment. In this study, we consider the randomness and uncertainty of cuttings movement to divide the transport process into parabola and collision motion between the moving particles and slope particles after falling on the slope surface of cuttings piles. Through specific analysis of the stress state of a single particle in the transport process and changes in momentum distribution of the particle swarm, the evolution model of the morphological distribution of cuttings piles and the nearby flow field is established. This model can quantitatively analyze the evolution law of the morphological distribution of cuttings piles under the action of ocean current and the disturbance law of the flow field near the cuttings piles caused by the invasion of cuttings particles. Comparing the measured data at an offshore drilling field and prediction results of the model of Sun et al. (2020), the relative error of the model amounts to less than 15%, which demonstrates its rationality. The simulation results show that the morphological distribution of cuttings piles and the nearby flow field change significantly under the action of ocean current, and the intensity of evolution is related to the current velocity and cuttings size, which is of great significance for the quantitative analysis of the evolution of cuttings piles under the action of ocean currents and accurate prediction of their morphological distribution.


Neft i gaz ◽  
2020 ◽  
Vol 3-4 (117-1118) ◽  
pp. 93-108
Author(s):  
Valentin-Paul TUDORACHE1 ◽  
◽  
Mihail MINESCU ◽  
Nicolae ILIAS ◽  
◽  
...  

The article presents an analysis of the realities faced by the operators in the oil industry, but especially the operators in the exploitation of the risers. Oil industry operators are focusing on drilling offshore wells to very deep water depths, as there are significant oil and gas resources that ensure high production. This analysis refers to the establishment of limit conditions that occur during drilling operations. We call this complex of factors the mechanics of riser. The article also refers to establishing the way of working in accordance with the API recommendations in force and obtaining theoretical results for offshore drilling in deep water. *Автор для переписки. E-mail: [email protected] 94 НЕФТЬ И ГАЗ 2020. 3–4 (117–118) БУРЕНИЕ These results are the starting point for simulation with the help of specialized software and obtaining results useful for the exploitation of risers in drilling wells in deep water. Drilling activity in deep water can only be done with dynamically positioned platforms, such as semisubmersibles platforms and drillship.


2021 ◽  
Vol 73 (10) ◽  
pp. 49-50
Author(s):  
Chris Carpenter

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202290, “Digital Documentation and Data Management for Offshore Drilling,” by Zhong Cheng, SPE, Xi’an Shiyou University and CNOOC, and Rongqiang Xu and Xiaolong Yu, CNOOC, et al., prepared for the 2020 SPE Asia Pacific Oil and Gas Conference and Exhibition, originally scheduled to be held in Perth, Australia, 20–22 October. The paper has not been peer reviewed. The industry is expending significant effort into using instrumentation and software to optimize operations in all domains for exploration and production to move toward the digital oil field. The complete paper describes an integrated geological-engineering data-management project covering all aspects of well-engineering work flows, with the objective of providing a continuous improvement platform to users. Introduction CNOOC has spent more than 20 years on the progression of information construction. A private cloud platform was completed in 2018, and the characteristics of oil and gas data and critical storage-management technologies were studied systematically. At the same time, nearly 20 kinds of drilling- operation analysis software have been developed independently. From the perspective of engineering technology, these provide real-time monitoring, remote decision-making, technical training, and other information resource services and support for offshore drilling operations. However, the following problems restrict the efficient operation of such projects: - Because of the lack of a unified data-integration-application platform, data sharing has not yet been realized. - In the process of real-time monitoring and remote decision-making, more engineering information based on drilling operations lacks the support of geomechanical data. - The knowledge base and case library to guide the prevention and handling of drilling-operation accidents have not been established. System-Target Analysis The design goals of the platform are embodied in three aspects: function, safety, and operability, while system performance requirements are summarized as adaptability, response speed, scalability, maintainability, and the effective-ness of failure-handling mechanisms. According to the functional requirements of different users for offshore-drilling cloud technical services, users generally are divided into three categories: headquarters decision-making managers, drilling-operation project teams, and system-operation and maintenance-service providers. System Construction Goals and Architecture Construction Goals - Chief among these was to build a geological-engineering integrated data-management platform. Another important goal was to build a case-management platform. An intelligent search engine is established to retrieve the corresponding disposal knowledge through a comprehensive information model. A knowledge-management subsystem is established, and users are linked with internal knowledge-management processes with the help of the cloud. The specific operation process is carried out in the private cloud, and the results are fed back to the user through the human/computer interface.


1973 ◽  
Vol 11 (3) ◽  
pp. 480
Author(s):  
J. M. Killey

As onshore oil and gas deposits are becoming more difficult to locate, and as the world demands for energy continue to increase at an alarming rate, oil companies are channeling much of their exploration activities towards offshore operations, and in particular, towards operations centered off Canada's coast lines. Because of the environment, offshore drilling presents problems which are novel to the onshore-geared oil industry. J. M. Killey discusses in detail many of the considerations involved in drafting the offshore drilling contract, concentrating on problems such as the liability of the various parties; costs; scheduling; pollution; conflict of laws; etc. Similarly, he discusses service contracts (such as supply boat charters; towing services; helicopter services; etc.^ which are necessity to the operation of an offshore drilling rig. To complement his paper, the author has included number of appendices which list the various considerations lawyer must keep in mind when drafting contracts for offshore operations.


2021 ◽  
Vol 9 (4) ◽  
pp. 399
Author(s):  
Mohamad Alremeihi ◽  
Rosemary Norman ◽  
Kayvan Pazouki ◽  
Arun Dev ◽  
Musa Bashir

Oil drilling and extraction platforms are currently being used in many offshore areas around the world. Whilst those operating in shallow seas are secured to the seabed, for deeper water operations, Dynamic Positioning (DP) is essential for the platforms to maintain their position within a safe zone. Operating DP requires intelligent and reliable control systems. Nearly all DP accidents have been caused by a combination of technical and human failures; however, according to the International Marine Contractors Association (IMCA) DP Incidents Analysis, DP control and thruster system failures have been the leading causes of incidents over the last ten years. This paper will investigate potential operational improvements for DP system accuracy by adding a Predictive Neural Network (PNN) control algorithm in the thruster allocation along with a nonlinear Proportional Integral derivative (PID) motion control system. A DP system’s performance on a drilling platform in oil and gas deep-water fields and subject to real weather conditions is simulated with these advanced control methods. The techniques are developed for enhancing the safety and reliability of DP operations to improve the positioning accuracy, which may allow faster response to a critical situation during DP drilling operations. The semisubmersible drilling platform’s simulation results using the PNN strategy show improved control of the platform’s positioning.


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