DEEPWATER DRILLING AND PRODUCTION SYSTEMS OVERVIEW

1979 ◽  
Vol 19 (1) ◽  
pp. 166
Author(s):  
J. M. McKinney

The petroleum industry is now involved in a highly significant exploration program to define the hydrocarbon potential of deepwater sedimentary basins. Within the last year, the ability to drill in waters deeper than 1300m has been demonstrated, and exploration plans for water depths down to 1600m have been announced. This paper reviews the industry's deepwater drilling experience and describes some of the unique technology required for a successful deepwater drilling venture. Drilling in over 1000m of water calls for more sophisticated, higher strength system components than are needed in shallower waters. Some of the differences between deepwater drilling procedures and more conventional shallow water techniques involve vessel carrying capacity, the use of a dynamic positioning system for staying on location, riser buoyancy materials, improved riser components and a multiplex electrohydraulic blowout preventer control system.Progress has also been made in developing production systems for use in water depths greater than 300m. The guyed tower concept, a product of Exxon's developmental work, has been demonstrated to be a cost-effective alternative to fixed-bottom platforms. The caisson vessel, designed to accommodate both drilling and production activities and to minimize motion caused by rough sea conditions, is an attractive option for operations in deep water. In addition, experience with a prototype of Exxon's subsea production system has demonstrated that this system is also ready for commercial use.

2021 ◽  
Author(s):  
Prabir Kumar Chatterjee

Abstract The present paper proposes an alternative to small offshore platforms with tripods and four-legged jackets by a single-pile structure for shallow water depths. The pile will be driven into seabed without a jacket and stability of the structure against environmental loads will be ensured by a few tie members connected to seabed with the help of specially-designed small concrete foundations. Tie members will be bolted to both the pile and the foundation. Four different cases of single-pile structures in three different water depths (20.0m, 31.5m and 15.0m) are presented. Omnidirectional waves of 10.0m height along with wind and current are considered in the study. Analytical method is suggested to simulate interaction of concrete foundations with soil that can be easily implemented in structural analysis. Structural design is performed as per API RP 2A working stress design method. The results indicate that the proposed single-pile structures have considerable reserve strength against failure due to extreme environmental loads and impact from medium sized boats.


1992 ◽  
Vol 29 (01) ◽  
pp. 25-35
Author(s):  
Richard D'Souza ◽  
Peter G. S. Dove ◽  
Donald G. Hervey ◽  
Donald J. Hardin

Industry interest in floating production systems in the Gulf of Mexico and elsewhere is increasingly pointing toward deeper water depths ranging to 10000 ft. In these waters, the moorings are an increasingly significant factor in the overall system cost. This paper presents important design considerations for deepwater mooring systems for permanently moored floating platforms. The engineering of feasible and cost-effective deepwater moorings requires substantive departures from conventional design and installation techniques. These include rethinking commonly accepted design criteria, the use of synthetic materials, alternatives to conventional catenary systems, increasing use of deeply submerged buoys, and innovative ideas for system installation. Issues addressed include: design criteria; the use of lightweight, high-strength materials such as aramid fiber rope in lieu of wire rope; analysis methods and procedures indicating the importance of quasistatic, dynamic, fatigue and probabilistic analyses; installation options and the benefits of maximizing deployment vessel options; the use of alternatives to a conventional chain/ wire catenary system; and design considerations and construction options of large-buoyancy, deeply submerged buoys.


2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.


Alloy Digest ◽  
1980 ◽  
Vol 29 (11) ◽  

Abstract JS777 is a high-alloy, fully austenitic stainless steel developed for applications where corrosive conditions are too severe for the standard grades of stainless steel. It also provides a cost-effective alternative to more expensive nickel-base and titanium-base alloys. It has relatively high resistance to stress-corrosion cracking and to intergranular corrosion. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-377. Producer or source: Jessop Steel Company.


Alloy Digest ◽  
2009 ◽  
Vol 58 (11) ◽  

Abstract Ancorsteel 4300 alloy ferrous powder simulates wrought steel compositions and is a cost-effective alternative to alloys requiring secondary processing. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on heat treating and powder metal forms. Filing Code: SA-611. Producer or source: Hoeganaes Corporation.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 119-120
Author(s):  
N. Østerås ◽  
E. Aas ◽  
T. Moseng ◽  
L. Van Bodegom-Vos ◽  
K. Dziedzic ◽  
...  

Background:To improve quality of care for patients with hip and knee osteoarthritis (OA), a structured model for integrated OA care was developed based on international treatment recommendations. A previous analysis of a cluster RCT (cRCT) showed that compared to usual care, the intervention group reported higher quality of care and greater satisfaction with care. Also, more patients were treated according to international guidelines and fulfilled recommendations for physical activity at the 6-month follow-up.Objectives:To assess the cost-utility of a structured model for hip or knee OA care.Methods:A cRCT with stepped-wedge cohort design was conducted in 6 Norwegian municipalities (clusters) in 2015-17. The OA care model was implemented in one cluster at the time by switching from “usual care” to the structured model. The implementation of the model was facilitated by interactive workshops for general practitioners (GPs) and physiotherapists (PTs) with an update on OA treatment recommendations. The GPs explained the OA diagnosis and treatment alternatives, provided pharmacological treatment when appropriate, and suggested referral to physiotherapy. The PT-led patient OA education programme was group-based and lasted 3 hours followed by an 8–12-week individually tailored resistance exercise programme with twice weekly 1-hour supervised group sessions (5–10 patients per PT). An optional 10-hours Healthy Eating Program was available. Participants were ≥45 years with symptomatic hip or knee OA.Costs were measured from the healthcare perspective and collected from several sources. Patients self-reported visits in primary healthcare at 3, 6, 9 and 12 months. Secondary healthcare visits and joint surgery data were extracted from the Norwegian Patient Register. The health outcome, quality-adjusted life-year (QALY), was estimated based on the EQ-5D-5L scores at baseline, 3, 6, 9 and 12 months. The result of the cost-utility analysis was reported using the incremental cost-effectiveness ratio (ICER), defined as the incremental costs relative to incremental QALYs (QALYs gained). Based on Norwegian guidelines, the threshold is €27500. Sensitivity analyses were performed using bootstrapping to assess the robustness of reported results and presented in a cost-effectiveness plane (Figure 1).Results:The 393 patients’ mean age was 63 years (SD 9.6) and 74% were women. 109 patients were recruited during control periods (control group), and 284 patients were recruited during interventions periods (intervention group). Only the intervention group had a significant increase in EQ-5D-5L utility scores from baseline to 12 months follow-up (mean change 0.03; 95% CI 0.01, 0.05) with QALYs gained: 0.02 (95% CI -0.08, 0.12). The structured OA model cost approx. €301 p.p. with an additional €50 for the Healthy Eating Program. Total 12 months healthcare cost p.p. was €1281 in the intervention and €3147 in the control group, resulting in an incremental cost of -€1866 (95% CI -3147, -584) p.p. Costs related to surgical procedures had the largest impact on total healthcare costs in both groups. During the 12-months follow-up period, 5% (n=14) in the intervention compared to 12% (n=13) in the control group underwent joint surgery; resulting in a mean surgical procedure cost of €553 p.p. in the intervention as compared to €1624 p.p. in the control group. The ICER was -€93300, indicating that the OA care model resulted in QALYs gained and cost-savings. At a threshold of €27500, it is 99% likely that the OA care model is a cost-effective alternative.Conclusion:The results of the cost-utility analysis show that implementing a structured model for OA care in primary healthcare based on international guidelines is highly likely a cost-effective alternative compared to usual care for people with hip and knee OA. More studies are needed to confirm this finding, but this study results indicate that implementing structured OA care models in primary healthcare may be beneficial for the individual as well as for the society.Disclosure of Interests:None declared


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Muhammad Ashar Naveed ◽  
Muhammad Afnan Ansari ◽  
Inki Kim ◽  
Trevon Badloe ◽  
Joohoon Kim ◽  
...  

AbstractHelicity-multiplexed metasurfaces based on symmetric spin–orbit interactions (SOIs) have practical limits because they cannot provide central-symmetric holographic imaging. Asymmetric SOIs can effectively address such limitations, with several exciting applications in various fields ranging from asymmetric data inscription in communications to dual side displays in smart mobile devices. Low-loss dielectric materials provide an excellent platform for realizing such exotic phenomena efficiently. In this paper, we demonstrate an asymmetric SOI-dependent transmission-type metasurface in the visible domain using hydrogenated amorphous silicon (a-Si:H) nanoresonators. The proposed design approach is equipped with an additional degree of freedom in designing bi-directional helicity-multiplexed metasurfaces by breaking the conventional limit imposed by the symmetric SOI in half employment of metasurfaces for one circular handedness. Two on-axis, distinct wavefronts are produced with high transmission efficiencies, demonstrating the concept of asymmetric wavefront generation in two antiparallel directions. Additionally, the CMOS compatibility of a-Si:H makes it a cost-effective alternative to gallium nitride (GaN) and titanium dioxide (TiO2) for visible light. The cost-effective fabrication and simplicity of the proposed design technique provide an excellent candidate for high-efficiency, multifunctional, and chip-integrated demonstration of various phenomena.


HPB ◽  
2020 ◽  
Vol 22 ◽  
pp. S186-S187
Author(s):  
J. Hawksworth ◽  
N.P. Llore ◽  
M.L. Holzner ◽  
P. Radkani ◽  
E. Mesler ◽  
...  

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 879
Author(s):  
Giuseppe Timpanaro ◽  
Ferdinando Branca ◽  
Mariarita Cammarata ◽  
Giacomo Falcone ◽  
Alessandro Scuderi

Climate change, food security, and the protection of the planet’s resources require the adoption of sustainable production models. Achieving sustainable development in the agri-food sector enables the creation of new opportunities for operators, guiding farmers towards more environmentally friendly practices and offering cost-effective results. Organic farming paradigms are promoted by the transformation of some harmful practices of conventional agriculture, such as the wide use of chemical products of synthesis, the deep workings that favor the erosive processes, the excessive use of nitrogenous fertilizers. There are still gaps in the knowledge of the real performance of some products that strongly support the local economic system of Sicily (Italy). The research aims to highlight the differences in environmental impact caused by the cultivation of organic early potatoes compared to the conventional regime and the same per kg of product obtained. To this end, the widely used methodology for comparing the environmental impacts of agricultural production systems is the Life Cycle Assessment, which allows us to highlight the phases in which environmental criticalities are most concentrated. An interesting agroecological picture of knowledge emerges, since organic farming is by definition an ecological model that supports the principles of the Green Deal, it often requires interventions to improve the yields obtained in order to achieve a positive result both in terms of cultivated surface and kg of product obtained.


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