bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of Multipurpose Port and Multiport Offshore Facilities
Authors: Frankel E.G. , Wilmes P.G. , Chelst K.G. 
Published: October 2008

Abstract
The choice between multipurpose and multiple specialized offshore port facilities requires many decisions which may be more effectively made using system analysis and simulation methods recently developed and discussed in this paper. Optimization of investment and other costs by allocating resources and developing utilization strategies are also presented.

Introduction
Decisions on offshore port location, type, and investment are a function of many economic, operational, technological, ecological, and environmental factors. Many of the questions relating to these decisions concern the relative advantage of one or more facilities to serve a projected commodity flow from assumed origins to defined destinations. These facilities may be of various types and capacities, as well as established in different alternative locations. Each type, capacity and location combination of an offshore facility system influences costs and transportation effectiveness. Other questions concern the advantages of single versus multipurpose offshore port facilities, where purpose is defined by the type and or form of commodities handled through it. A number of analytical and simulation methods or models have recently been developed which address these problems from a total transportation systems point of view.
The purpose of this paper is to summarize a description of these methods and discuss their potential application. The discussion is divided into:Methods for determining effects of number, location, capacity, use, investment and other costs of offshore port facilities to meet a given demand, andMethods for analyzing or simulating port design, use and policy decision as they effect multi versus single purpose ports.
It is recognized that these two types of decision problems are interrelated and both types of analysis are usually required to converge on an effective set of decisions.

1.0 Multiple Offshore Port Systems Analysis
The multiple offshore port problem consists of determining the number, location, capacity, use, investment and cost of a system of one or more offshore ports to meet the demand for commodity flow from other origin ports to inland destinations or vice versa. This problem, discussed in Ref. 1, can be presented as a transportation network or a linear programming model. Various solution techniques recently developed at M.I.T. (Ref. 3-6) are presented.

Approximate Algorithm for Selection of Optimum Offshore Ports
The basic problem of offshore port selection can also be formulated as a mixed integer programming problem in which we minimize an objective function such as:(Mathematical equation available in full paper)
Aj = quantity required at inlandpoint j (per unit time) N = the number of trade routes of interest to offshore port development.
The second constraint guarantees that if port i is closed all trade routes to the port are closed and if port i is open that at least one trade route to the port is open.
A North Atlantic Deep-Water Terminal
Authors: Soros Paul , Hakman Peter A. 
Published: October 2008

Abstract
OTC Number 1828 Paper "A North Atlantic Deep-Water Terminal.
Reference is made to a Study on "Offshore Terminal System Concepts" completed in September 1972 for the U.S. Maritime Commission. General conclusions are briefly presented. The Northeast U.S.is identified as the area most urgently requiring a deep-water marine terminal to handle crude oil to meet the energy crisis. A conceptual design is presented of a terminal located off the Delaware Bay for trans-shipping crude oil and later solid bulks.

Background
The U.S. Maritime Administration authorized a study to be performed by Soros Associates in 1971 entitled, "Offshore Terminal System Concepts", the results of which were released in September 1972.
One of the first conclusions reached was that VLCC's cannot be accommodated at any of the existing ports on the East and Gulf Coasts. Another general conclusion was that foreign crude oil imports in VLCC's to the North Atlantic Region represent the primary national need, with similar but somewhat less critical needs existing for the Gulf and West Coast areas. The technical, environmental and political conditions at the Gulf and West Coast locations are generally favorable and indications are that the type of facilities envisioned will soon be realized. Unfortunately, the problems on the East Coast are more complex and difficult to solve.
The existing oil refinery capacity in the North Atlantic region is about 75 million tons per year. The crude oil for these refineries is supplied primarily by tanker, partly from the Gulf region with the remainder from foreign sources. As crude oil production declines while demand increases in the Gulf Region, coastwise shipments will gradually diminish and eventually stop, leaving the North Atlantic refinery feed entirely to foreign imports. The East Coast demand by the late seventies is estimated at about 200 million tons per year increasing by the mid eighties to over 300 million tons per year. The capacities of the existing refineries in the East could be expanded to 200million tons, but the 300 million ton level would require major new grass- roots refinery development. In recent years, no firm has been successful 'in the East in obtaining the necessary approvals to develop such new refineries.

Risks w1th the Existing Conditions
Importing crude at the 200 million tons per year level represents a more than800 percent increase in throughput compared to 1970 imports. A great number of 40,000 DWT to 60,000 DWT tankers navigating long distances in busy and restricted channels through congested harbor traffic all the way to Philadelphia or up the Kill Van Ku11 in New York would pose a serious environmental risk.
The use of these relatively small tankers under these circumstances combines maximum risk with maximum potential environmental damage.
Determination of Dynamic Characteristics of Offshore Platforms from Random Vibrations
Authors: Earle E.N. , Mandery W.L. 
Published: October 2008

ABSTRACT
The dynamic response characteristics of three offshore production platforms have been determined. The technique used involves curve fitting to match a theoretical spectral density function to the spectral density function computed from measured random vibration. Results in the form of natural frequencies and damping are presented for the three structures. These results show that the damping in offshore platforms is about 3.5 percent of critical.

INTRODUCTION
Structures of all sizes and shapes are usually subjected to time varying loads. These loads can be created by Wind, waves, earthquakes, and/or machinery. The effect on the structure, its dynamic response, is of utmost importance to the design engineer since the dynamic response of a structure can exceed the static response by a significant factor. If a structure were to be loaded such that the frequency of the load was approximately equal to the natural frequency of the structure, the stresses in the members caused by the dynamic load would far exceed the stresses caused by the static load applied to the structure. The size of the dynamic stresses within the structure is dependent upon not only the size of the external load, but also by the amount of damping of the structure.
Theoretical methods are available for computing the natural frequencies and the dynamic response of various types of structures. These methods usually require that an estimate of the amount of damping be made to complete computations. For the typical deepwater offshore drilling platform, which is anchored to the ocean floor by piling, it would be desirable to know the actual damping in the structure and the structure's natural frequencies, to compare with theoretical predictions and/or estimates.
Acquiring random vibrations data from an offshore platform and developing a method to analyze these data were the approach used to determine the actual damping and natural frequencies of an offshore platform.

Data Acquisition
The data gathering system is shown in - Figure 1. Three 3-dimensional geophones sense the vibrations. The signals from these are sent to an amplifier which -amplifies or attenuates the signals. These are then fed to a tape recorder. The signals are monitored on an oscilloscope before, during, and after recording. Each of these elements will be discussed in more detail below.

Geophones
The geophones used are Geospace Corporation Model No. HS-10-1 LP-3D units. These each contain three separate one-dimensional units mounted along three mutually orthogonal axes inside a pressure tight case which keeps out moisture. Each individual unit consists of a coil which is attached to the case through springs in such a way that the coil can move relative to the case.
Analysis of Drilling Ship Performance
Authors: Turrentine Robert E. , Huff Gene W. , Oglesby Glen F. 
Published: October 2008

ABSTRACT
Rising costs and the increasingly complex nature of the offshore drilling industry have created a need for more technical methods of evaluating operating performance. Analytical procedures have been established to integrate theoretical data, drilling rates, environmental information and vessel motion and mooring data to produce operating efficiency indices. These methods may be employed for making cost studies of actual past operations or for forecasting results of projected operations.

INTRODUCTION
The operation of offshore drilling units which normally operate-in a floating mode, while anchored on location, is a relatively new, but rapidly expanding and evolving industry. Initial work dates back almost twenty years, but the business as we know it today is about ten years old. The successful development of this method of drilling and exploring the submerged land areas of the world has come about, to a great extent, through certain departures from conventional oil well drilling equipment and techniques. As a result, floating drilling has achieved clear identity as a distinctive segment of the offshore business, and as such, requires specific, though, somewhat sophisticated standards for measurement of performance.
In general, the procedure for measuring performance is scaled into three steps:prediction of behaviour, which covers advance testing of vessel design, as well as forecasting of actual environmental conditions and the resultant effects on the unit;definition of parameters, measurement and recording of actual data;analysis of the use of time and costs to measure productivity.

THE OCEAN ENVIRONMENT
The single outside factor which bears most heavily on all offshore operations is the effect of ocean or sea conditions on performance efficiency. This is usually translated broadly into percentage of "Waiting on Weather," as a percentage of total time. As we will discuss later, this subject is substantially more complex than the term may indicate initially.
Several important developments have enabled us to both understand the ocean environment better, and to be able to operate more efficiently in it:
More frequent and more reliable weather forecasting, resulting from better data and improved data gathering procedures; satellite information, for example.Better definition, standardization and understanding of terms, so that operating people can better anticipate severe conditions and prepare for the effects of winds, rough seas and other elements.Improved ability to describe actual conditions through:–New Equipment (wave buoys)–Better technical knowledge and Understanding–Experience in a wider variety of the world's oceans
The reliability of weather forecasting has improved appreciably during the past few years, particularly in the Gulf of Mexico and in The North Sea, but not without considerable effort on the part of the oil industry.
An Acoustic-Mechanical Method for Re-establishing Communications with Subsea Systems
Authors: Sheffield J.R. , Masoriheimer R.A. 
Published: October 2008

INTRODUCTION
9 In bf'f'shore petroleum operations, it is essential to establish or re-establish physical communications with a subsea system. Divers accomplish this task in relatively shallow water. However, as oil operations move to deeper water and more adverse environmental conditions, diving in many instances has become very difficult. These conditions have led to the investigation of methods for remote establishment of communication and installation of equipment. One such operation involves installing guidelines on suspended exploration wells in the deep waters of the Santa Barbara Channel. This is considered a typical example of the requirements for establishing communication between a vessel and a subsea system. This paper is restricted to the acoustic instruments commercially available and the mechanical equipment designed to install the guidelines.
To establish communications between a vessel and a subsea system, whether operation is active or suspended, requires three steps:locating the general area by navigational techniqueslocating the exact point of entry andcompleting the process by mechanically establishing physical communications.
This discussion is limited to the details of Steps 2 and 3; however, an inaccurate navigating system could require long-range acoustic devices (Step 2) that are not commercially available and would have to be built.
The design and development of the required mechanical equipment will depend, to a certain extent, on the acoustic devices available. On the other hand, the job to be done and the hardware needed for the job may indicate a preferable acoustic device. Thus, a brief discussion of the over-all system will be presented first. A description of the available acoustic devices will be followed by a discussion of the mechanical equipment. Finally, the mating of both systems for testing will be discussed in detail.

GUIDELINE RE-ESTABLISHMENT
The 'guideline re-establishment system consists of a drill string assembly, lowered from a drilling vessel that is anchored in the near vicinity of the well, and an ocean-floor assembly consisting of a corrosion cap, guide tube, and reflector mounted on the wellhead within the guide structure (Fig. 1). The drill string assembly contains the acoustic device and all four guidelines to be installed. In practice, the vessel is positioned by moving in response to signals from an acoustic device so that the drill string assembly is directly over the ocean floor assembly and ready for stabbing. When stabbed, this drill string assembly will orient mechanically, install all four guidelines, then dog into the ocean floor assembly so that the' reflector, guide tube, and corrosion cap can be removed from the wellhead. Thus, when the string has been pulled and the guideline installation system laid down, the well will be clear and ready for running the BOP and riser. Before any of this can happen, however, the wellhead must be located.
Smoothbore Flexible Riser for Gas Export
Authors: Crome Tim , Binet Eric , Mjøen Stig 
Published: October 2008

Abstract
This paper describes the development of a novel design of smoothbore riser for dry gas applications. It has been developed for use on the Statoil operated Åsgard field located about 200 kilometres off mid Norway.
Shortly after start-up of gas export from, what was then the world's largest semi-sub, Statoil's Åsgard B platform, a serious noise and vibration phenomenon was identified in the gas export system. This system consists of a manifold on the platform topsides connected to parallel flexible risers linked to a subsea Export Riser Base which feeds the gas into the 42" export pipeline to Norway. The noise, essentially a high pitched whistling, and resulting vibration, caused two fatigue failures of small bore piping fittings on the topsides manifold, leading to gas leaks on the platform. There were also concerns related to the subsea piping. The source of the noise, in this dry gas system, was related to vortex shedding of the gas flow past the internal carcass in the flexible risers.
Initially two roughbore risers were installed; this was subsequently increased to a total of four including one spare. The increase to three operating export risers had been planned from the start of the project to reflect increased export volumes from Åsgard. However, while it was now possible to manage the gas flow such that the noise and vibration was controlled, this could not be achieved without unacceptable pressure losses along the length of the flexible risers. This problem was related to longer term operation of the Åsgard Transport System as the export volume through it, and hence the required operating pressure, increased with the inclusion of export from new fields, such as Kristin.
After comprehensive work with export system monitoring, dynamic simulations, and assessment of alternative export arrangements, Statoil invited Technip to validate the concept of a flexible smoothbore structure for the Åsgard B gas export riser system. This paper describes the background for, and special measures implemented in, the design of the world's first smoothbore flexible riser for gas export. This design is such that noise from the risers is eliminated while, at the same time, a smoother internal bore significantly reduces the pressure losses along the riser, allowing the full potential of the Åsgard Transport System to be achieved. The first smoothbore gas export riser was installed, in late Autumn 2006, as a replacement for one of the existing standard roughbore risers.
Hence, the new application of smoothbore riser technology to the novel gas export riser design for Åsgard, gives several benefits;noise and vibration issues are eliminated,pressure losses are reduced andenvironmental benefits are achieved from the subsequent reduction in need for compression.
Prediction of Pipelaying Equipment Performance In Hostile Environments
Authors: Pearce B.K. , Kishpaugh J.A. 
Published: October 2008

ABSTRACT
In order to predict the performance of pipelaying equipment in hostile offshore environments and to establish incentives for the development of new equipment and techniques, we have developed a computer model that simulates the pipelaying process. Use of this tool has shown quantitatively that semisubmersible laybarges should be cost effective in rough water areas such as the North Sea. Simulation results also quantify the advantages of using automatic welding and wide-truss stingers.
The computer simulation model is designed to predict probable installation costs and times for completing offshore pipeline construction projects, taking into account not only work interruptions due to weather, but also equipment failures, and other randomly occurring events such as pipe buckles and weld defects. The Monte Carlo simulation technique is used to model the occurrence of these uncertain events. By making a large number of simulations of a pipeline construction project, installation time and cost predictions can be made on a statistical basis; i.e., probability distributions of installation time and cost are developed for the project.
This paper describes the computer simulation program, shows how it, is used, and presents some equipment evaluations for the northern North Sea and the Grand Banks of Canada.

INTRODUCTION
Over the past few years a number of ideas for improving offshore lipelaying operations have been suggested including the use of laybarges with better motion characteristics, faster pipe joining methods, and improved stinger designs. However, the advantages of such proposed improvements have not previously been quantified in terms of potential savings in construction time and cost. It is difficult to do this because of the fact that it is simply hard to predict the performance of any particular piece of pipelaying equipment. This is true primarily because of the influence of weather on pipelaying operations and because there is not a one-to-one-correspondence between downtime and inclement weather. However, in addition to weather downtime, pipe abandonment and recovery times must also be accounted for, as well as downtime for mechanical failures and pipe damage.
In order to account for these uncertainties, we have developed a computer model that simulates the pipelaying process by using the Monte Carlo technique2, 3 This is a "probabilistic" estimating approach and provides not only a single-valued, best estimate of pipelaying performancebut also gives additional information, i.e., (1) a measure of how much better or worse results might be and (2) the risk associated with any particular estimate. Monte Carlo simulation is being widely used for analysis of problems involving uncertainty.
The pipe1aying simulation model provides a means of (1) estimating pipeline construction time and c8st (2) selecting pipe1aying equipment, (3) evaluating contractor bids3 and (4) quantifying the potential advantages of proposed improvements.
Subsea IOR: Keynote Introduction
Authors: Utseth Rolf H. , Strøm Steinar 
Published: October 2008

Abstract
Statoil, as a major offshore operator, has established demanding ambitions with respect to increased oil recovery from our subsea fields. We see a large gap, appr. 15%, in recovery from our fields produced from fixed platforms relative to the subsea developed fields, even though the quality of the reservoirs is basically the same. To a large extent this gap is related to the high cost in subsea operations in general and well operations in particular. This paper includes:A listing and brief introduction to the technologies being developed and implemented.A generic evaluation of how the technologies will influence on the recovery from Statoil's existing subsea fields
The paper will act as a bridging document between the other presentations and papers in the joint Statoil/FMC session at OTC 2007.

Background
Statoil envisages fulfilling the demanding requirements to significantly improve the oil recovery from subsea fields. Statoil's current average oil recovery from subsea fields is 45,1%, which is high compared to other operators. The recovery from our platform developed fields is close to 60%. The ambition is to increase the recovery from subsea fields to 55% by 2008, meaning that by 2008 the 55% ambition should be reflected in the resource plans for each individual asset summing up to 55% as an average within the company. Statoil has its current focus on the Norwegian Continental Shelf (NCS), the applicable technologies however are highly relevant also for other parts of the world, such as in deep waters and arctic areas.
The current cost level in subsea drilling and well operations is determined as probably the main obstacle to increase the oil recovery. Consequently, the efforts are to a large extent focused in this area. Statoil has incorporated Riser less Light Well Intervention (RLWI) as a corporate service across asset borders. We intend to do the same with Through Tubing Rotary Drilling (TTRD) in subsea wells, the operations will commence in 2007 utilising the dynamically positioned rig Stena Don.
The next step will be to develop the next generation of subsea wells (Subsea MMX) to significantly reduce the cost of a new well together with sufficient flexibility to tie in new wells over time. Along with the subsea system itself, it is essential to focus on the drilling and well solution and ultimately the rig solution (light unit).
Other technologies such as Subsea Processing and Wet Gas Compression are also very important technologies that are being developed.

The ambitions and deliveries

General
Based on experience from platform operations Statoil has established goals and ambitions within the subsea segment. The R&D focus areas are shown in figure 1.
Figure 1: Statoil R&D focus areas within the subsea segment(available in full paper)
There are ambitions linked to each of the focus area, these are:Identify drainage points and intervention needsLow cost drainage pointsLow cost well interventionIncreased fluid handlingReduced wellhead pressureIntegrated operations