bluuebunny/crossref_metadata_2025_split huggingface dataset:
Innovative Concepts for Marginal Fields (Advanced Monotower Developments)
Authors: Smith M.T. , Marks V.E. 
Published: October 2008

ABSTRACT
The braced mono tower provides a safe, functional and cost effective solutionfor topsides up to 500 tonnes, with up to 8 wells and standing in water depthsof up to 70 metres. It is both simple in concept and structurally efficient. The superstructure is supported by a single column which is stayed by threesymmetrically orientated legs. A broad mudline base is also provided to limitpile loads. The final concept offers complete protection to the risers andconductors from ship impact, as all appurtenances are housed within the centralcolumn.
The basic design philosophy of the low intervention platform is to minimise theonboard equipment to that vitally needed to produce hydrocarbon. The concepteliminates the life support functions that on a normal North Sea platform cancontribute up to 50% of the topside dry weight. A system of Zero BasedEngineeringis used that ensures each item of equipment contributes more to theNPV of the platform than the fully built-upthrough life cost. This effectivelyeliminates the operator preference factor and the "culture" cost.

1. INTRODUCTION

1.1 General
The design of offshore platforms for hydrocarbon production from the North Seahas recently gone through a period of rapid change. This process has occurredas a response to the increasingly difficult economic conditions over the lasttwo years. The increased competitiveness in design proposals has been matchedby a willingness on the part of Operators to accept more economic solutions tooperational requirements.
Amongst the areas where developments have shown major improvements is in thedesign of shallow water lightweight platforms. This paper traces the designdevelopment of one group of lightweight platforms for usein the NorthSea.

1.2 North Sea Environment
Figure 1 shows the UK sector of the North Sea. Two areas are of specialinterest - the Southern North Sea area which is a gas basin covered by shallowwater less than 50m in depth, and the southern edge of the Central North Seabasin, which contains oil, condensate and gas fields at water depths up to100m.
This paper refers to developments primarily in the Southern Basin area.
These areas are of special importance, as they are mature basins with a largepopulation of marginally economic small fields awaiting low cost developmentschemes before production can be justified.

2. ECONOMIC BACKGROUND

2.1 Gas Demand
The Western European gas market has shown strong growth over the last 15 yearsand is expected to continue to grow at the current rate for some time to come. The development of new high efficiency combined cycle technology andenvironmental concerns have resulted in very strong growth of gas demand forthe power generation industry. This is currently the fastest growing sector ofthe European gas industry.
In the UK, the liberalisation of gas supply from the original British Gasmonopoly position has given a very sharp increase in the proportion of gasfired power generation, as shown in Figure 2.
The Changing Role of the Remotely Operated Vehicle in Offshore Operations
Authors: Mair J. , White J. 
Published: October 2008

ABSTRACT
The ROV's role in satisfying the requirements of the offshore production industry has been one of constant change over the years.
As technical, operational and commercial experience has been gained, new and more demanding challenges have been identified.
This paper demonstrates the capabilities of ROVs and their associated technology in meeting these new demands dictated by deepwater operations, increased safety requirements and low oil prices.

INTRODUCTION
ROVs and their associated intervention tools have been gradually eroding the well established role of the diver.
This is clearly evident by the reduction in the number of divers to date supporting the industry compared with the increase in the number of ROV's and their associated personnel.
Historically a large quantity of equipment and numerous personnel were required to support a simple diving system whose duties on a drilling rig for example were establishing wellhead guide wires and the occasional operation of valves. The introduction of the ROV however was in itself a traumatic period and most divers have their own ROV recovery tale to tell.
These early machines had not been designed for the rigours of offshore use and were therefore generally unreliable.
The ROV's potential was recognised, however, which encouraged companies to invest in these machines and improve their performance to acceptable levels.
In addition to the machines themselves, their launch and recovery systems were also improved. Early launch systems such as articulated cranes. (commonly fitted to trucks) have been replaced with purpose designed "A" frames and towers etc. to cater for the general increased weights of the modern ROV, its tether management system and to provide a contingency for intervention equipment etc.
In addition, systems are now generally designed to comply with offshore lifting regUlations e.g. "DnV Code of Practice for Offshore Lifting Appliances' which ensures their ability to cope with the dynamics associated with their intended use.

CURRENT CAPABILITY
Today it is now widely recognised that the ROV is the primary support system on drilling rigs.
Recently, however. we have seen numerous instances where the ROV has been required to perform activities which may be considered beyond the ROV's commonly perceived capabilities.
Such projects highlight that ROVs can perform tasks that were previously considered unlikely and will encourage new tasks to be considered with confidence.
It also became evident that all work class ROVs do not have equal compatibility and that certain tasks will require the higher specification models to be used.
Sealability of API R, RX, & BX Ring Gaskets
Authors: Fowler Joe R. 
Published: October 2008

ABSTRACT
This report presents work done to determine the sealability limits of API R, RX, and 8X gaskets. The work included finite element modeling and full scale testing.
The research teaches that bolt stresses of 15 to 30 ksi are necessary to seat the gaskets. If these seating loads are not achieved, the gaskets will likely leak at design pressure, particularly for gas service. If the flanges are properly made up, the sealability limits in API Bulletins 6AF and 6AF2 are too conservative and can be eliminated for non cyclic service.

INTRODUCTION
API Spec. 6A (1)* give specifications for equipment with pressures to 20,000 psi and temperatures as high as 650º F. This equipment utilizes metal ring-type joints for all end connectors in the specification. These end seals are of three basic types, RX, R and BX. BX gaskets are generally used for the higher pressures.
Recently API has sponsored a considerable amount of research into the load capacity of the various end connectors in Spec. 6A. This research has resulted in Bulletins (7) which provide the users a prediction of the combined pressure, moment, and tension load capacity of the various connectors, All of this research has been done, however, with the assumption that the gaskets will leak when the applied loads relieve the initialpre-load on the gaskets. The calculations for this were necessarily crude and the assumption has not beenverified. Accordingly, it was desired to perform a general research study on metal gaskets in order to provide users the background of the design of these gaskets to enable one to intelligently assess the degree of safety againstleakage in the end connectors.
In practice, ail of these gasket types have apparently worked reasonably well. BX gaskets were explained in a 1964 paper (2) and were introduced to achieve the benefits of pressure energized gaskets in high-pressure flanges. R gaskets, which are not designed to be pressure energized, and RX gaskets, which are pressure energized, do not makeup with the flange faces face to face. The BX gaskets, however, do generally makeup face to face. Type R gaskets have been in service since the 1930's. (Reference 1, 13th Edition, 1981). ASME (3) publishes procedures for calculated gaskets seating and retaining codes for R type gaskets, but not for RX or BX gaskets.

RESEARCH OBJECTIVE
The objective of this research (13) was to develop general theories which could be used for design and prediction of gasket performance for R, RX, and BX gaskets. Fundamental to this is a prediction of leakage as a function of flange pre-load or flange face movement, Seating load prediction is also an important factor for designers.
The philosophy of this research project was to use the finite element method and full-scale testing to help confirm and validate general theories of behavior. The general theory of behavior which was evaluated was that leakage is likely to occur when the contact pressure between the seat and the seal is less than the applied internal pressure that is being sealed.
Load and Resistance Factor Design Case Histories
Authors: Brand P.R. , Whitney W.S. , Lewis D.B. 
Published: October 2008

ABSTRACT
Casing accounts for 10% to 30% of the total well cost. The oil and gas industry has historically used working stress design (WSD) methods in the design of casing strings, This method requires the load to be defined as an estimate of the maximum anticipated load, while the strength is defined as a lower bound of the materials strength. The designer must assure that the minimum allowable stress of the material is not exceeded, by separating the load and the strength by a safety factor that is fixed by company guidelines.
Load and Resistance Factor Design (LRFD) is a reliability based design philosophy, which explicitly takes into account the uncertainties that occur in the determination of loads and strengths. The LRFD format was first developed in the 1930's in USSR and Europe for use in the Civil Engineering industry. Its development and use has continued in Civil Engineering practices and is now widely accepted in many industry codes.
As a reliability based design philosophy, the engineer is allowed to select a probability of failure that is commensurate with the consequence of failure. This allows the engineer to accept a probability of failure that maximizes the utilization of the casing design, thus improving the economic indicators on the investment.
Beginning in the late 1980's and early 1990's, several efforts were undertaken to develop LRFD for casing design. This paper describes the basic LRFD philosophy and shows two examples of well designs developed using LRFD and compares them to the designs previously developed using WSD. The impact on the well cost and deliverability are discussed for each design. The issue of probability of failure and the impact on the well design are also discussed. The material selection criteria and the qualitysystem that were developed in concert with LRFD are also described

Working Stress Design
WSD is the traditional approach to design that ensures adequacy by computing elastic stresses under maximum anticipated load and comparing them with allowable stresses. The safety of the structure is assured by ensuring that for each element, elastically computed stresses do not exceed an allowable stress, that is a preset fraction of the yield strength of the material. The ratio of the yield strength to the actual stress is known as the safety factor.
The allowable safety factor, is set in an empirical manner and reflects the companies policies with respect to safety and risk. Dueto the uncertainty in the loads, there is not a consistent definition of design loads or minimum factors of safety throughout the industry, except where mandated by government regulations.
Although working stress is conceptually simple and has worked well in most cases, it is not without problems. Some examples of these problems are:it is overly conservative,it does not give the engineer any insight into the degree of risk or safety of the design,it has no risk balanced capabilities,it treats all wells the same,there is little justification in the safety factors.
The Business Impact and Value of 3-D Seismic
Authors: Aylor W.K. 
Published: October 2008

Abstract
3-D Seismic has had a profound and lasting impact on the hydrocarbon exploration and production industry. It is a technology which is often excellent at assessing the risk associated with trap definition, seal and reservoir distribution, the very parameters which are the most critical to optimizing the economics associated with E&P projects, This paperdiscusses Amoco Corporation's experience with 3-D Seismic when used for new field rate acceleration, older field extension, and wildcat exploration. Its emphasis is on assessing the value added by 3-D by reviewing recent E&P experiences in a post-appraisal mode and then in applying the lessons learned from these analyses and case histories to potential new projects.
This work is significant because it first assesses the impact 3-D has had on a large number of business situations at Amoco, that is, it is based on data collected on 159 3-D surveys acquired at Amoco between 1991-1994. Second, it uses the data collected from these surveys and applies the business improvements observed in the data to typical international business opportunities to quantify, in expected value $ terms, the value that the technology brings to an average project. Finally it looks at project economics not only from an oil company perspective, but from the standpoint of a host government, with a discussion of insights and implications of the data, economics and techniques utilized.
3-D can add significant value to exploration and production activity. The value added depends on expected cost, revenue, timing and risk changes, and generally is more valuable the earlier it is applied. If 3-D is appropriate for particular projects (that is if the underlying risk associated with a projeet can be significantly impacted by 3-D), host governments stand to realize much more from 3-D than do oil company partners. Delay in the use of 3-D can significantly erode the ultimate value 3-D can add to the project. Quantified economic examples are used to illustrate all of these conclusions.

Introduction
During the past 5 years, hardly an oil industry technical or business symposium has taken place, or a trade journaI has been published that has not either mentioned or explicitly illustrated the viability of 3-D seismic as a E&P tool. In spite of the enthusiastic claims however, most geoscientists have at one time or another experienced disappointing results with 3- D. Indeed, for some companies, 3-D remains a novelty, an exception to their way of doing business.
A very legitimate question remains then: to what degree has 3-D added value to the E&P situations where it has been utilized? Has value been added when prospects or areas have been condemned by 3-D? How often does 3-D return disappointing results, for example where dry holes are drilled even after 3-D has been used?
Axial capacity of offshore piles driven in dense sand
Authors: Jardine R.J. , Overy R.F. 
Published: October 2008

Abstract
The paper reports a previously unpublished tension load test to failure on a 38.lm long, 660mm diameter steel pipe conductor driven in predominantly dense sands at the Leman BD site in the Southern North Sea. The case history is used, with other pile test data, to evaluate and calibrate new design methods that have been developed from recent research. As an example, the findings are applied to a study into the axial capacity of piles driven at the nearby Leman AD H site.
The Lemon soil conditions are described, and the driving records and test result are presented. The new design methods are then summarised and applied to analyse the conductor's capacity. A comparison with other pile capacity prediction methods is made and the results are used, in conjunction with other data to demonstrate that a modified form of the new method can give accurate predictions for offshore pipe piles.
Applying these approaches the Leman AD 11 platform's foundations indicates axial capacities greater than expected previously. Increases in compressive and tensile capacities of at least 15 and 50Y0, respectively, are predicted. Research is continuing to fizrther refine the new methods for calculating axial capacity.

Introduction
Shell UK Exploration and Production operate groups of offshore jacket structures in the southern North Se% some of which were installed more than 25 years ago. To help assess the effects of a possible reconfiguration of loads applied to the Leman AD 1[ structure, a study was made of the axial capacity of its foundation piles.
Leman AD 11 has piles that were driven in predominantly dense sands, for which standard axial capacity calculation methods are unlikely to offer accurate predictions. Reviews such as those by Focht and O'Neill, Briaud and Tucke, Jardine and Christoulas, Tang, Randolph Chowb or Gavin and Lehane show that conventional design methods for piles driven in sand are relatively unreliable.
New approaches were considered necessary and the study was shaped to:. Interpret the ground conditions and operational soil parameters at Leman AD 11on the basis of existing site investigation data,Assess data from a conductor pull-out test performed at the nearby Leman BD site in 1969 and the recent field tests on driven open-ended pipe piles at Dunkirk described by ChowUse the above to test the reliability of a new Imperial College ([C) method for calculating the shaft resistance of open-ended driven piles in dense North Sea sands and. Apply the new methods, taking account of the recent research concerning base capacity described by Hight et alg and Chowb.
Mini 3D for shallow gas reconnaissance
Authors: des Vallieres T. , Enns D. , Kuhn H. , Parron D. , Lafet Y. , Van Hulle D. 
Published: October 2008

Abstract
The Mini 3D project was undertaken by TOTAL and ELF with the support of CEPM (Comite d'Etudes Petrolieres et Marines) to define an economical method of obtaining 3D seismic HR data for shallow gas assessment.
An experimental 3D survey was carried out with classical site survey techniques in the North Sea. From these data 19 simulations, were produced to compare different acquisition geometries ranging from dual, 600 m long cables to a single receiver.
Results show that short offset, low fold and very simple streamer positioning are sufficient to give a reliable 3D image of gas charged bodies, The 3D data allow a much more accurate risk delineation than 2D HR data.
Moreover on financial grounds Mini-3D is comparable in cost to a classical HR 2D survey. In view of these results, such HR 3D should now be the standard for shallow gas surveying.

Introduction
Advantages of the 3D seismic method compared to classical 2D for oil and gas exploration are obvious, particularly in applications requiring high spatial resolution. However, exploration 3D puts heavy constraints on data acquisition and processing. Costs are consequently high.
High resolution 3D seismic investigation is not commonly used so for such purposes mainly because cost reasons in spite of the technical advantages.
The objective of the Mini 3D project was to investigate economic HR 3D seismic for shallow gas risk assessment. The strategy was to try to define the simplest data acquisition configuration capable of 3D visualization of hazardous shallow gas that is consistent with the equipment currently used in the site survey industry.
The work progressed as follows :
The first step was to acquire a full, state of the art HR 3D seismic and to process the data with full processing sequence. The subsequent 3D volume was by definition the reference.
Further steps were taken to simulate reduced acquisition geometries by means of successive decimations. The results were then compared to the reference volume

Data acquisition

Site selection
To be representative, to possess the following attributes:proven shallow gas occurrencesprevious sumying for shallow gaswell data in the immediate vicinity the experimental site hadlocation in an active oil and gas producing region Such a site was found in the British sector of the North sea, in block 22/7 operated by TOTAL.

Acquisition equipment and recording parameters
The objective was to acquire a HR 3D volume corresponding to a drilling site making use, to the greatest extent possible, of standard 2D HR equipment including : vessel, seismic source, and streamer. The desired highest HR geometry was a 6,25 × 12.5 m bin size to be acquired along lines 12.5 m apart.
Field and Laboratory Data from Pile Load Tests in Calcareous Soil
Authors: Randolph M.F. , Jeer H.A. , Khorshid M.S. , Hyden A.M. 
Published: October 2008

Abstract
Grouted piles are used extensively in offshore deposits of calcareous soils, because of the relatively low shaft capacity of driven piles. Two construction techniques may be used: drilled and grouted piles, where steel pipes are grouted into predrilled oversize holes; and grouted driven piles, where driven pipe piles are pressure-grouted through valves distributed along the pile shaft The paper describes the results of a comprehensive set of field and laboratory tests on grouted piles that were undertaken in calcarenite in Australia, to validate pile design for the calcareous deposits which predominate off the coast of Australia. The experimental results were used to validate and calibrate a numerical load transfer model, that simulates degradation and accumulation of permanent displacement under cyclic loading. The paper provides a recommended design approach for grouted piles in calcareous soil, with due account taken of construction technique, pile diameter and soil strength as indicated by the cone resistance.

Introduction
Drilled and grouted piles are commonly used for offshore foundations in the compressible calcareous soil deposits found off the coasts of countries such as Australia, India and Brazil. Despite their prevalence, design rules remain largely empirical, with a limited database of field and laboratory tests.
Over the last decade, an alternative construction method for grouted piles has emerged. Instead of grouting a steel tubular into an open-hole (a relatively costly and potentially unstable sequence), piles are first driven into the formation, and then pressure-grouted along their lengths through pre-installed valves. Rickman and Barthelemy have described this so called ‘grouted driven pile’ construction method, although the technique has still to be used for a major offshore structure.
EconomicalIy, there appear to be a number of advantagesfor grouted driven piles:The pile may be installed in one piece, using a single installation method (driving), compared with a driven primary pile, drilling out of the primary and hole for the insert pile, and installation of the insert pile.In principle, grouting may start from close to the seabed, rather than from below the primary pile.The pile diameter remains at the maximum that will fit the jacket sleeves throughout its length, with no step down from primary to secondary.
From a risk viewpoint, the potential danger of hole instability for the drilled and grouted pile must be weighed against the uncertainty of grout coverage for the grouted driven pile. From a technical viewpoint the pressurisation of the grout for the grouted driven pile is likely to entail higher shaft capacity than for a drilled and grouted pile. However, the difference may be of secondary importance compared with risk and eeonomic considerations.