bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations Relating to Non-Condensable Gasses in a Vapour Chamber: Phase B of the Dover Project
Authors: Aherne A. L. , Birrell G. E. 
Published: December 2007

Abstract
Non-Condensable Gasses (NCG) are gasses such as carbon dioxide, hydrogen sulphide, methane and nitrogen which can be present in a SAGD steam chamber but do not condense into the liquid phase to any large degree. Recent theoretical and laboratory work has shown that these gasses can enhance the thermal efficiency of SAGD without a significant reduction in productivity. In the laboratory, NCG has been shown to finger into the bitumen ahead of the main steam chamber, bringing with it heat and pressure.
This paper looks at temperature and pressure data from the world’s most mature SAGD pilot, Phase B of the Dover project, to determine whether naturally occurring NCG in the form of solution gas can be detected fingering ahead of the main steam front. The paper looks at the propagation of the steam chamber front by examining thermocouple data from observation wells drilled within and outside the SAGD pattern. The steam chamber propagation velocity, which also determines the velocity of the pressure front, is calculated. The pressure build-up profile is used to determine the pressure diffusivity constant, which in turn determines where the pressure front would be located without any NCG fingering.
The actual pressure front is compared to the predicted. In every case the actual pressure front travels between five and twelve meters ahead where one would expect it from the theory.
Integrated Optimization of Horizontal Well Performance
Authors: Tian Shubao , Zhao Gang , Zhang Qi 
Published: December 2007

ABSTRACT
It is crucial to accurately predict the horizontal well flow performance so that the optimum production can be achieved. The horizontal well flow performance has generally been conducted under the assumption of uniform-influx profile along the horizontal wellbore, which neglects the pressure loss in horizontal wellbore and can cause an unreasonable well design. This paper developed a model to optimize the horizontal well performance by integrating the fluid flow in reservoir, the flow in sand control zone near wellbore, the flow in horizontal wellbore and tubing into an integral hydraulic system. The variable mass multiphase flow characteristics in the horizontal wellbore and the fluid lifting behaviors in tubing are also taken into account. In addition, the effects of reservoir properties, fluid properties and wellbore characterisrics and different well completions, involving open hole, slotted linear, pre-packed linear and gravel pack, on well performance are analyzed. The optimum well design is determined accordingly following the criterion presented.
It has been shown that the integrated model enables not only the better understanding of the complexity of the interaction between reservoir and wellbore, but also the overall optimum and coordinated operation of the whole system. For example, in the case of accurate prediction of the liquid-gas flow characteristics in wellbore, it is necessary to build detailed flow pattern model because the liberation of a large amount of gas can significantly affect the overall pressure loss, tubing lifting and production. Another example is that most pressure in the whole hydraulic system is consumed in tubing lifting, therefore effective tubing lifting design also helps obtain the optimum production. Using our integrated model we have identified the different effects among different kinds of sand control well completion methods. We have also shown that the well length, wellbore diameter and producing gas-oil ratio are the major factors affecting the well production.
Laboratory Simulation Of A Two-Phase Geothermal Reservoir
Authors: Castanier Louis , Bories Serge 
Published: December 2007

Abstract
An experimental simulation of a two-phase flowing geothermal reservoir was conducted using a bench-scale model. Twenty runs were performed, using unconsolidated sand as the porous medium in the first step, and the data were verified using a lumped-parameter numerical model. The collection of thermodynamic data, including temperature, pressure, enthalpy, and liquid saturation, yielded interesting results for energy extraction efficiency in the process of in-situ vaporization and for the influence of the following physical parameters on the behavior of a two-phase geothermal parameters on the behavior of a two-phase geothermal reservoir:–porosity–speed of decompression–heat influx–initial liquid saturation

Introduction
This study deals with some aspects of fluid flow and energy transfer in porous media, with emphasis on the behavior of a geothermal reservoir in two-phase flow. Although much experimental work has been done on this subject during the last ten years, different approach in the design of experimental apparatus allowing simultaneous; knowledge of all the physical parameters of the porous media seemed indicated. parameters of the porous media seemed indicated.

REVIEW OF THE PARAMETERS THROUGH A MATHEMATICAL MODEL
This mathematical model is a classic adaptation of the work of Luikov. Its purpose is to determine the physical parameters which influence the heat and mass transfer during in-situ vaporization. The following assumptions were made:the porous medium is homogeneous and deformable,fluids and porous medium are supposed to be a fictitious equivalent continuous medium,friction is neglected, andcapillary effects are neglected, except as included in relative permeabilities.
The basic equations are:
Continuity:
Flow:
Enthalpy:
Equations of State:
For a definite fluid, heat and mass transfer will depend on:–porosity,–nature and grain size of the porous medium,–initial thermodynamic conditions,–liquid saturation, and–exploitation conditions.

EXPERIMENTAL APPARATUS
The apparatus was designed to check the influence of the physical conditions on the behavior of a piece of porous medium of simple geometrical shape, in which the heat and mass transfer during the self-vaporization process are monodirectional (see Figs. 1 and 2). A typical experiment can be described as follows:–The porous medium and the thermocouples were introduced into the cylindrical cell.–The ends of the cell were closed.
Description Of The UK Christchurch Bay Wave Force Project And Some Initial Results-Part 2
Authors: Bishop John R. , Holmes Patrick 
Published: December 2007

Abstract
Preliminary results of spectral and Preliminary results of spectral and probabilistic analysis of wave and wave-induced loads probabilistic analysis of wave and wave-induced loads on the main tower and wave staff of the Christchurch Bay experiments are presented. The results obtained to date show reasonable agreement with linear random-wave solutions and the influence of the non-linear drag element of the loading is apparent. The data needs to be expanded with particular reference to fluid kinematics in the presence of waves and currents, and their effect on wave loading.

Introduction
Part II of this paper discusses the results obtained to date from an analysis of the Christchurch Bay data in spectral and probabilistic terms.
Again, it is noted that the results presented here are interim in that further analysis and cross-checking of the data is continuing.

2. THEORETICAL BACKGROUND

2.1 The Wave Conditions
A method of predicting wave induced forces on offshore structures which has found increasing application to design problems in recent years is based on the concept of considering the wave motion as a stationary random process.
Incident wave conditions are expressed in terms of the surface-elevation spectrum, Sn(w), such as the Pierson-Moskowitz or Jonswap formulations. These Pierson-Moskowitz or Jonswap formulations. These can be related to the usual parametric descriptions of wave conditions in terms of the significant wave height, H1/3, and the zero-crossing period, Tz, and it is sometimes appropriate to use a 'spreading-function' giving a two-dimensional spectrum Sn(w, 0) representing a three-dimensional sea-state.
In parallel with the spectral formulation are the probabilistic properties of the surface-elevation which, under certain assumptions, can be considered as a Gaussian process with probability density function, (p.d.f):
(1)
It has been shown by several authors, notably Longuet-Higgins, that for certain conditions the p.d.f of wave-height is approximated by the Rayleigh density function which in cumulative form is given by:
(2)
Thus the wave condition can be described by the spectrum, the Gaussian p.d.f of surface-elevation and the Rayleigh p.d.f of wave height.

2.2 The Loading Model
Morison's equation for the in-line horizontal force per unit length on a vertical cylinder represents the total force as the sum of a non-linear drag component and a linear inertial component.
(3)
where
being the density of sea-water; Cd and Cm are the drag and inertia coefficients, u is the horizontal water particle velocity and u is the acceleration. particle velocity and u is the acceleration. There are obviously deficiencies in this representation, for example, transverse forces are not included and the coefficients Cd and Cm are considered to be constants. However, the wide-spread use of the Morison equation in design and, as yet, the absence of a reliable alternative justify its use as the 'core' of spectral and probabilistic extentions.
P. 187
Experience With Surface Controlled Sub-Surface Safety Valves
Authors: Medley Edward L. 
Published: December 2007

Medley, Edward L., Amoco (UK) Exploration Company

Abstract
There are 92 surface operated, wireline retrievable sub-surface safety valves installed in Amoco (UK) Exploration Company's portions of the Leman, Indefatigable and portions of the Leman, Indefatigable and Rough Fields. These valves are fail-safe in operation and offer a back-up shut-in safety system to all other safety shutdown devices on a platform. Therefore, each valve is function tested monthly.
There are three types of valves in use in these fields, the bypass type, the ball type and the flapper type. Records covering an eight year period were reviewed to provide data to determine a failure rate provide data to determine a failure rate for each type of valve. Individual graphs were prepared showing each time a valve was pulled, and these were reviewed and summaries given to show how failure rates were determined.
Based on the review, the following failure rates were determined:
Type No. of No. of Failure Valve Tests Failures Rate
Bypass 3472 28 0.8%
Ball(old 595 68 11.4%type)
(new 172 4 2.3%type)
Flapper 1651 26 1.5%

Introduction
Amoco has been producing gas from the southern North Sea since April 1969 and until July 1977, 101 development wells had been completed in the Leman, Indefatigable and Rough Fields. The fields produce from the Rotliegendes Sandstone from depths ranging from 6600' to 8500'. In these fields two completion schemes are used, one with 4 1/2" tubing, the other with 5 1/2" tubing. The 4 1/2" tubing was used in 36 wells on the first three platforms in the Leman Field, but all later completions used 5 1/2" tubing.
As part of the completion equipment, a surface operated, wireline retrievable, subsurface safety valve is set in the tubing, approximately 100' below the sea bed. These valves are referred to as mudline safety valves (MLSV). These are fail safe, since hydraulic pressure from the surface must be maintained to keep them open. A concentric tubing/casing annulus is used to transmit this hydraulic control pressure. Due to the type of operation and the location of these valves, they provide a back-up to all other safety shut-in devices on a platform. They will automatically close if any of the surface hydraulic control equipment is damaged, or if the Christmas tree is damaged, and due to their location within the well, they should be immune from any damage above the sea bed.
Each MMSV is function tested once per month. This test is conducted in the following manner:With the well flowing, the hydraulic annulus pressure is bled off, causing the MLSV to close.
P. 257
Legislation And Its Application To The Control And Use Of Submarine Pipelines On The UK Continental Shelf
Authors: Paddock Kenneth F. 
Published: December 2007

Introduction
Prior to the introduction on 1 January 1976 of the Petroleum and Submarines Act 1975, there was no legislation under which the design and operation of submarine pipe-lines could be effectively controlled. There was however legislation which had to be complied with - as it still does with some modification to the application - and which wasCoast Protection Act 1949 - as extended by the Continental Shelf Act.Dumping at Sea Act 1974.
The Coast Protection Act 1949 is administered by the Department of Trade, (the Marine Division being those most involved), and is the department having the responsibility for the safety of navigation. The consent of the Secretary of State for Trade was originally required for the entire route of the pipe-line, but it has now been agreed with them that in waters deeper than 100 feet (33 metres) no hazard is offered to any vessel by a pipe-line and so no conditions are imposed by that department if the pipe-line is in water exceeding that depth.
The Dumping at Sea Act 1976 is administered by the Ministry of Agriculture, Fisheries and Food (MAPF) in English waters, and in Scottish waters, taken as north of latitude 56 °, it is administered by the Department of Agriculture and Fisheries for Scotland (DAFS). In the offshore context these offices have the interest of the fishing industries to consider.
The Petroleum and Submarine Pipelines Act 1975 now embraces for submarine pipe-line purposes the requirements of the Dumping at Sea Act 1974 but it is important to point out that only that which is to form a part of the pipe-line, including anything intended to give it protection or insuring stability, is covered by the Act. Anything disposed of over the side of a lay barge or other vessel engaged on pipe-line work is obviously not within the category of part of the pipe-line, and so such disposal would constitute an offence under the Act. On the other hand any chemically treated water - inhibited test water for example - is not part of the pipe-line and although a consent is required before it is ejected into the sea, the consent in this case is given under the Petroleum and Submarine Pipelines Act 1975. The view being taken that it is part of the integrity testing and so connected with the safety of the pipe-lines.
Monitoring And Structural Response Of Steel Offshore Structures
Authors: Brown David R. , Huckvale Stephen A. 
Published: December 2007

Abstract
There are many different levels at which the performance and response of a steel structure can be studied. This paper reviews various schemes and outlines the results of recent work in the North Sea.
The scope of the work includes a theoretical dynamic analysis of the structure, the design, installation and performance of a vibration monitoring system and the computer analysis of measured vibration spectra for the purpose of evaluating the technique as a means of monitoring the structural integrity of the installation.
The system described is an offshore platform inspection tool capable of utilizing the divers time more effectively by directing them to areas of structural concern.
Vibration spectral energy distributions for a N. Sea platform are presented as well as a more convenient form of presentation designed to aid the handling and interpretation of the data.

The Need for Monitoring
For some time, it has been clear that it is very desirable to develop systems of remote monitoring to enhance diver inspection techniques: when the statistics are studied, it is evident that such schemes are really essential. There are 52 fixed steel jacket structures in the British sector alone in the North Sea, the great majority of which are in water depths greater than 50m. Within the certification requirements there is a demand for re-certification every fifth year and a programme of annual surveys. In practice this is often replaced by a fairly steady and systematic series of annual surveys by divers. There are three main causes of failure, corrosion, fatigue and accidents, and it is very difficult to select areas that are most likely to have suffered. Finding that 10% of the structural members are in good condition is only superficially reassuring.
The real point is to see if instrumentation can concentrate diver and other inspection activity on areas of greatest vulnerability. In the British sector of the North Sea, there are about 600 nodes on steel jackets that are below the 50 metre depth. This depth is generally recognized as the limit of air diving. With an average length of 23m of weld per node, this suggests about 14km of weld that requires inspection. The estimated cost of saturation diving, manned and unmanned vehicles used in the northern North Sea is about £50 million in 1977 and about 40% of this is concerned with inspection of members: the rest is concerned with items such as scour, anodes, cleaning of marine growth, etc. (statistics on maintenance requirements are taken from Ref. 1).
What Should Oil Managements' Goals Be To Satisfy Investors?
Authors: Fourton Leslie K. 
Published: December 2007

I am highly honored to have been asked to participate in your National SPE meeting and to have the opportunity of discussing with you some of the factors which we in Wall Street feel influence the attitudes of investors toward petroleum equities. The securities of your companies vie with those of companies in other industries and their investment appeal is influenced in many ways.
Your committee chose the title for this paper because it felt that a discussion of management goals with equity valuation as a basis of orientation might be particularly useful and timely. The fact that oil securities are selling at 12 to 15 times earnings compared with 19 times for the Dow Jones Industrial Average shows the decline in investor favor in recent years. I believe, nevertheless, that you represent an investment group which offers the same outstanding values and opportunities today as it has in the past. The question is what causes this undervaluation of your industry and what can be done about it.
I have asked many widely-recognized senior petroleum analysts both in Wall Street and in institutions such as mutual funds, insurance companies and banks how they would approach this subject of management goals to satisfy investors. It was almost amazing how similar were the replies. Everyone said: "They should pay higher dividends." These replies were not as facetious or superficial as some may think, although I don't believe higher dividends is the only or the most important way to look at this subject.
Now, irrespective of what final position we may take, there is a broad fertile area we may explore in attempting to more precisely satisfy investors. To do this, each of you must first determine what kind of stockholders you wish to attract and satisfy. There are decidedly different methods of appealing to institutional investors, the individual sophisticated investor and the small stockholder. Since there is insufficient time, however, to discuss the desires of each type of investor, it may be best to proceed in a general sense.
First, we should examine the aspects of the petroleum industry which are of particular concern to investors in general. Second, we could briefly examine the fundamental position and prospects of the industry itself. Third and lastly, knowing what is of concern and what there is to work with, we may be able to develop some constructive thinking on management goals which may satisfy investors.
I believe there are eight major areas of concern to investors and it may be helpful at this point to review them briefly.
Economic Benefits To The UK Of North Sea Oil
Authors: Ferguson Carol Cecilia 
Published: December 2007

Abstract
Economic study of the North Sea has applications for Government and Industry. For Government. quantification of North Sea benefits influences policy in diverse areas such as taxation levels. exchange control and economic management in general. Loosening of economic restraints may benefit industry by reducing taxation levels, restoring business confidence and stimulating investment.

INTRODUCTION
This paper identifies three important areas where the UK benefits from North Sea Oil production. These are:Balance of PaymentsUK Gross National ProductNew Offshore Oil Service Industry
The paper quantifies the contribution of oil to the UK economy where possible and evaluates the impact of changes in the exchange rate and the oil price. The likely effect of Government refinery policy and depletion policy are also reviewed.
The main conclusions are positive - that the UK economy will enjoy a higher rate of growth in the medium term. Economic management will be less constrained by Balance of Payments and exchange rate considerations. Energy self-sufficiency will also have important political implications. The UK will develop expertise in oil exploration. production and related services to enable it to compete effectively overseas, particularly in the more hostile offshore areas. There are also some dangers to the UK economy, with the possibility of sterling becoming overvalued, thus accelerating the decline of the UK's traditional industries.

RESERVES AND PRODUCTION
It is a little over a decade since the first commercial North Sea oil discovery was made. Production is now being obtained from nine UK fields and a further eight are under development. Total recoverable reserves from these seventeen fields are estimated to be a little over 9.5 billion barrels. Additional reserves of 1.7 billion barrels will probably be recovered from a further ten fields which are likely to come under development over the next three or four years or so enabling them to start contributing to UK production from late 1980 onwards. New that production is building up, the North Sea can be said to be maturing as an oil province, although by comparison with other producing zones, it is a relatively unexplored area. It is very likely therefore that although it is believed that most of the largest structures have been identified and tested, that the North Sea will continue to produce further commercial discoveries in the future.