bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Model Tests in the Design of Single Point Mooring Terminals
Authors: Pinkster J.A. , Remery G.F.M. 
Published: October 2008

ABSTRACT
This paper gives a broad outline of model tests with single point mooring systems. This includes the purpose of the model tests, the information necessary to set up test programs, the scope of tests, the characteristics simulated, measurements carried out, possible sources of errors and the analysis of results. Furthermore, examples of test results are given which show phenomena characteristic of s.p.m. terminals. Finally, some of the phenomena observed during tests and a source of uncertainty in existing methods to calculate the behaviour of s.p.m. ship systems are discussed.

INTRODUCTION
Single point mooring terminals are, as the name implies, facilities of small horizontal dimensions, to which large vessels are moored by means of a bow hawser or by any other means which allows the vessel to rotate 3600 around the mooring point. Generally, the single point mooring terminal can have two functions. Primarily, it affords a safe mooring to the vessels in question. Secondly, it can form a link in the chain for the transport of oil.
The single point mooring terminal can assume many forms as is shown in Fig. 1. The most common is the Catenary Anchor Leg Mooring system (CALM) consisting of a flat cylindrical shaped buoy which is anchored to the sea floor by means of up to 8 chains. This system employs the properties of the catenary to supply the elasticity required when holding large tankers in open seas. The Single Anchor Leg Mooring system (SALM) consisting of a cylindrical buoy attached to a heavy base on the sea floor by means of a single pre-tensioned anchor chain, obtains its elasticity from the angle between the single anchor leg and the vertical. Enlarged version of the single point mooring terminal are the Exposed Location Single Buoy mooring (ELSBM) and the SPAR. The second of these does not only fulfill the function of mooring point and link in the oil transport chain, but is also used as a storage unit.
The types of mooring system described here, are excepting the ELSBM and the SPAR primarily used in water depths of up to approximately 150 ft. Some of the systems can with modifications be used for even greater water depths, however.
Rigid spar buoys connected to the sea floor by means of a universal joint are at present being designed. These consist of a buoy at the surface rigidly connected to a frame work which extends down to the base. This type of mooring is intended for water depths of 300 ft. or more. Finally, there are the mooring towers which consist of a slender open frame work fixed to the sea floor. Unlike all other systems, this type of mooring terminal does not contribute to the total elasticity of the system.
Generally, the tankers are connected to the mooring terminal by means of large circumference synthetic ropes which are part of the operating equipment of the terminal itself. In one case where the vessel is permanently moored to serve as storage space, the connection consists of a rigid arm.
Bas in Oscillations In an Offshore Harbor
Authors: Ho Rong Tai , Bomze Herman Tai 
Published: October 2008

ABSTRACT
A numerical method using an integral equation approach derived from Green's theorem has been developed for calculating the steady-state, wave-induced oscillations inside an offshore harbor of arbitrary shape surrounded by the open sea. It solves the outside diffracted wave field as well as the radiating wave field due to the interaction between the harbor and the ocean waves through the harbor entrances. The method was verified by checking against known solutions. It was then used to study the water surface oscillations inside a breakwater enclosure protecting a proposed floating nuclear power plant in the Atlantic Ocean. Results of the investigation are presented in this paper.

INTRODUCTION
Due to the rapid growth of energy demand and considerations of environmental impact, among others, a new concept has been developed for locating nuclear power plants offshore in the coastal zone. Public Service Electric and Gas Co. (PSE&G) of New Jersey has proposed to install two 1,150-mw nuclear power plants (FNP's on moored floating platforms of a standardized design. The plants Will be protected by a semicircular rubble-mound main breakwater facing the ocean and a straight closure breakwater facing the coast, located about 3 miles offshore slightly north of Atlantic City. The proposed project has been named the Atlantic Generating Station (AGS).
When a basin is connected to the open sea, the water surface inside the basin is subjected to the excitation of the incident waves propagating from the ocean into the basin entrance. A basin can be considered as a multiple-degree-of-freedom mechanical system with its appropriate inertial, dissipative, and restoring characteristics. The responding oscillation inside the basin is dependent upon the period of the incident wave and the basin and entrance configurations. This response may result in an amplification of wave heights inside the basin at certain incident wave frequencies, i.e., at the resonant frequencies of the basin system. It is essential to understand the characteristics of basin oscillations in order to determine the motions of the floating platforms and the required strength of their moorings.
Most existing numerical methods for basin oscillation analysis are developed for ordinary harbors inland of straight coastlines, so that the solution for the diffracted wave field outside the harbor is available immediately. Such harbors have only one entrance. In such a case, the problem reduces to a solution of the radiating wave due to the interaction between the harbor and the ocean wave. The AGS harbor presents a different problem since it lies offshore, requiring solution for the diffracted wave field, and since it has two openings to the sea.

LITERATURE REVIEW
Miles and Munk1 investigated the case for a rectangular basin connected directly to the open sea and obtained a balance at the harbor mouth between the ocean wave entering the basin and the wave radiating from the harbor mouth back into the open sea by means of an integral equation in terms of a Green's function.
A Probabilistic Investigation of Foundation Design for Offshore Gravity structures
Authors: Kraft Leland M. , Murff James D. 
Published: October 2008

INTRODUCTION
Gravity structures play a prominent role today in North Sea oil development. These structures are not supported by piles as are most ocean structures but rather sit directly on the ocean bottom, and depend on their foundation geometries and large weights to resist severe environmental loadings. A number of structural and foundation configurations have been proposed; however, attention will be restricted in this discussion to a general configuration typical of the most prominent structures being constructed at present (1975). An example of a gravity structure is illustrated in Fig. 1. The structure foundation consists of a large caisson placed directly on the unprepared seabed surface. The deck is supported by large columns extending from the caisson. Various combinations of steel and reinforced concrete have been proposed, but the majority of structures are being constructed almost entirely of reinforced and pre-stressed concrete.
One of the primary engineering concerns with these structures is foundation design. Because of the variability associated with the environmental forces as well as the basic soil properties, this problem lends itself well to modern probabilistic procedures. Such procedures provide a rational, quantitative means for evaluating uncertainties affecting appropriate design, even though a of subjectivity will always remain in any such evaluation. The probabilistic method requires the engineer to formally and consistently recognize the variability of many of the important design parameters. The method gives management and others responsible for setting design criteria an opportunity to appraise cost-benefits of design levels required for given reliability safety levels. It also quantifies reliability to permit direct camparison with other options.
This paper presents a method for analyzing the reliability of gravity structure foundations in terms of simple loading and resistance models. The sources of variability in estimating resistance to loads are discussed with particular emphasis placed on the nature of soil property variability and uncertainty. These concepts are illustrated through an analysis of a typical gravity structure foundation.

THE RELIABILITY MODEL
Reliability as defined in this paper is a measure of the probability of survival. For example a perfectly reliable foundation corresponds to a zero probability of failure. Because of uncertainties in environmental loads and soil properties plus the ever present uncertainties due to simplifying assumptions in the analytical methods, the chance of failure is always present although acceptably small for proper designs.
Characterizing the structure's resistance as a function R and the load acting on a structure as a function L then the failure probability Pf is simply the probability that L is greater than R. For structures of the type presented in Fig. 1 we can reasonably consider the load and resistance to be statistically independent so that(Available In Full Paper)
Cathodic Protection Experience In Cook Inlet, Alaska
Authors: Barrett S.L. , Taylor J.M. 
Published: October 2008

Abstract:
Amoco Production Company operates four of fourteen platforms in the Cook Inlet of Alaska. Amoco's ten years of underwater corrosion and cathodic protection experience in the Cook Inlet environment are reviewed. Tests show that 90-100 ma/sq.ft. are necessary to polarize the Cook Inlet structures where high tidal velocities are prevalent. Further, impressed current densities of 60 ma/sq.ft. maintain the cathodic protection as evidenced by the presence of a cathodic scale in the lower portions of the splash zone of the structure legs. An underwater corrosion coupon program was run to verify underwater protection and effects of structure shielding are described. Field data on protection are also confirmed by laboratory data.

Introduction:
The Cook Inlet is a marine estuary near Anchorage, Alaska. Amoco Production Company operates four of the fourteen offshore drilling and production platforms located in Cook Inlet. These four structures are jointly owned by Amoco, Atlantic Richfield, Phillips, Skelly and Standard of California. Platform Baker was installed in 1965, while Platforms Anna, Bruce and Dillon were installed in 1966. At the Amoco-operated platforms, water depths range from 65' to 110' (mean low water) with tidal ranges as high as 30' (-5' to +25' MLLW). Peak tidal currents are 10 FPS (7 MPH). The Cook Inlet is characterized in winter months by large floating pans of ice generally l' to 2' thick and as much as ½ mile across.
Seasonal variation in fresh water run-off dramatically affects the estuary turbidity and salinity. Glacial silt concentrations as high as 440 ppm usually make the water opaque. Salinity varies as much as 22% between summer and winter. Recognizing further that the water temperature varies from 28° F in the winter to 55° F in late summer, the observed resistivity of the Cook Inlet waters is from 0.43 ohm-meters at 28° Fin the winter to 0.29 ohm-meters at 55° F during periods of peak run-off in the summer. The waters of Cook Inlet are also oxygen-saturated to the ocean floor year-round.

Platform Construction:
Jackets of the four Amoco-operated platforms are of similar construction. As depicted in Figure 1, the structures are four-legged with cross-bracing located well below the water surface to minimize ice loading. The jackets are constructed of three types of material including Kaisaloy 50 MV® high strength steel in the submerged high stress areas and Sheffield Lo-Temp® steel in the high stress areas exposed to the atmosphere. Finally, the legs were provided with a ½" thick sacrificial corrosion wrap of A-36 steel in the tidal splash zone. This material is external to the structural portion of the leg. Average submerged unpitted structure surface areas vary-from 23,000 sq.ft. on Platform Bruce to over 50,000 sq.ft. on Platform Baker. All calculated current densities have been based upon unpitted surface areas although the actual surface areas can be expected to be significantly greater due to pitting.
Design and Construction of a Marine Terminal for North Sea Oil in Orkney, Scotland
Authors: Trainor Robert W. , Scott J.R. , Cairns W.J. 
Published: October 2008

ABSTRACT
In the U.K. North Sea, Occidental of Britain, Inc., a subsidiary of Occidental Petroleum Corporation, is operator for a group consisting of Occidental Petroleum, 36.5 per cent; Getty Oil International (England) Ltd., 23.5 per cent; Allied Chemical (North Sea) Ltd. 20.0 per cent; Thomson Scottish Petroleum Ltd., 20 per cent. In March 1972 the U.K Government granted to the Occidental Group a petroleum production license for six blocks covering approximately 316,000 acres of the North Sea and exploration drilling started immediately. In January 1973 the first discovery was made in Block 15/17, 100 miles east of Wick, Scotland by Odeco's "Ocean Victory" and subsequent delineation drilling confirmed the commercial viability of the Piper Field (see Figure 1). The decision was taken to develop the Piper Field by means of a fixed steel platform and a pipeline to a shore" terminal. This paper describes the search for a suitable terminal site, the environmental studies that were made to satisfy the requirements of national and local government and thus obtain the necessary planning consents as well as a review of the engineering design and construction of the terminal itself. The selection of the terminal site on the island of Flotta in Orkney was made in May 1973; formal application for planning approval was made in July 1973 and planning consent was received in late JanuarY1g74 when site construction started. The first phase of the terminal development i.e. to handle the production of the Piper Field at 250,000 BPOD will be completed in June 1976 at a total cost of $164 millions.

INTRODUCTION
The initial problem facing Occidental was to select a suitable site for the terminal; obviously a prime consideration in selecting a terminal site was its proximity to the Piper Field; with marine pipeline costs running at approx. $1.1 millions per mile for the 30 inch mainline from the Piper Field this consideration was the determinant for the initial selection of the trial terminal sites. Nine locations were selected for examination; these included sites in the Shetland Islands, Orkney and on the Scottish mainland. Studies were made using all available maps, charts and weather records and site visits were made to enable estimates to be made of development costs, probable berth occupancy and operating costs. An analysis of these variables coupled with the differential costs of the pipeline for each case enabled a further screening process to be carried out and as a result, three sites were selected for detailed study; two of these sites were located in Orkney and one on the Scottish mainland.
Further detailed study of each site was made and discussions were held with the Scottish Development Department, the Highlands and Islands Development Board and the Orkney Islands Council.
Economic Models of Subsea Pipeline Connectors
Authors: Daley Gregory C. 
Published: October 2008

ABSTRACT
Economic models analyze the sensitivity of some of the costs encountered in the eleven under sea pipeline connections on the 34" oil line from Ekofisk to Teesside for hydroball/ hydrocouples, hyperbaric chambers, and one-atmosphere chambers. The economic models are summarized by a graph showing the cost for eleven 34 inch connections as a function of the number of productive work days required per. connection. The results do not prove that one system is better than another, but do show the sensitivity to the day rates and productive work days required for each system.

INTRODUCTION
Economic models analyze one time costs and day rate charges for three systems. The first model involves hydroball/ hydrocouples installed by a lay barge, by the Arctic Surveyor, and by a vessel larger than the Arctic Surveyor. The eleven Ekofisk installations were made from lay barges and the Arctic Surveyor. This experience is utilized by the models. Other costs relate to equipment costs, protective covers, and inspection programs.
Costs for installing eleven connections with a hyperbaric system are developed into the second economic model. Costs for burying the splice piece are included.
The eleven Ekofiskpipeline connections are assumed to be riser connections to evaluate the one atmosphere chamber system. The equipment costs and other costs of the Lockheed System are modelled. At the time of this writing, the system is not applicable for mid line connections and therefore could only have been used on five of the eleven Ekofisk connections. This lessens the accuracy of the Ekofisk - Lockheed model.

THE EKOFISK OIL .AND GAS PIPELINES
The huge reserves of oil and gas discovered in the Ekofisk field by the Phillips Norway group in 1969; and later increased by the discovery of six adjoining fields, could only be economically transported by pipeline. This decision has resulted in the construction of two of the largest and longest marine pipelines ever to be built as shown in Figure 1. The large capacity of each line has also required the construction of two intermediate booster platforms on each of the pipelines, believed to be the first ever constructed. Phillips Petroleum Company Norway, operators of the Phillips Norway Group, acting on behalf of the Norpipe A/S, has completed the oil pipeline and is entering the final stages of completion of the gas pipeline. During 1973 and oil and gas pipeline; of this amount, 464 miles were marine pipeline. The 34" o.d. 220 mile oil pipeline from Ekofisk to Teesside, England has a capacity of one million barrels per day and the 36" o.d. 275 mile gas pipeline from Ekofisk to Emden, Germany, has a capacity of 2.28 billion cubic feet per day. Both the oil and gas pipelines are owned by Norpipe A/S a 50-50 joint venture of the Phillips Norway Croup and Statoil, the Norwegian national oil company.
Deep Ocean Mining - Technology Transfer From And To The Offshore Drilling Industry
Authors: Williams D.W. , McBride C.M. , Kinnaman S.C. 
Published: October 2008

ABSTRACT
In late 1977, a dynamically stationed drillship, SEDCO 445, will be used in the North Pacific Ocean to deploy equipment for recovering 5000 short tons of manganese nodules. This pilot test will be conducted in 5300 meters of water for an international consortium and will utilize many proven designs and techniques of the offshore drilling industry. These proven techniques and some of the newly designed methods will be presented in this paper to emphasize the desirability of a continuation of technology transfer between this newly emerging mining industry and the existing offshore drilling industry.

INTRODUCTION
Deep ocean mining activity has taken a dramatic upward swing during the last 7 years. In 1970, Deepsea Ventures successfully conducted a manganese nodule mining test in 740 meters of water and became the first company to attract attention to the feasibility of hydraulically mining nodules. Increased metals prices, the need for potential stable metal sources, the talk of metal cartels, and improved technology have contributed to the formation of four active international consortiums. All companies are actively exploring the area between the Clarion and Clipperton fracture zones shown in Figure 1.
Ocean Management, Inc. located in Bellevue, Washington, is one of the four active. ocean mining groups. OMI represents and manages the activities of the four equal shareholders who are INCO (Canadian), DOMCO (Japanese), AMR (W. German), and SEDCO (U.S.)
During the last quarter of 1977, OMI will commence a pilot mining test using the dynamically stationed drillship, SEDCO 445 as illustrated in Figure 2. SEDCO is responsible for a major portion of the shipboard hardware design and operation during the planned 7 to 8 month test period. Many of the techniques to be used for operating the vessel and deploying equipment have been proven by the offshore drilling industry.
In contrast to the proven methods planned for this operation, some unique tools and procedures will be used. It is anticipated that some of the special mining equipment and procedures can be used by the offshore drilling industry in their search for fossil fuels in deep water.

CONTRIBUTION OF DRILLING INDUSTRY

Ship Design
With offshore operations extending into deeper water and more inhospitable environments, this decade has seen the development of the drillship progress from a tethered ship-shaped drilling platform into an efficiently designed, dynamically positioned mobile drilling vessel. Operational range and capability have been extended dramatically over the past decade. Similarly, the volume of engineering and operational experience necessary to produce these achievements has grown considerably. It is this wealth of knowledge of shipboard operations in a deep ocean environment that has provided the greatest of dividends to the newly emerging deep ocean mining industry.