bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Borehole Gravimetry for Reservoir Characterisation and Fluid Saturation Monitoring
Authors: Popta J. V. , Heywood J. M. T. , Adams S. J. , Bostock D. R. 
Published: December 2007

ABSTRACT
This paper describes the results of a field application of borehole gravimetry to measure secondary gas saturations in a fractured limestone reservoir. Owing to its deep-reading capability and insensitivity to near-wellbore effects, the borehole gravimeter succeeded where conventional cased-hole logging methods had failed. Borehole-fluid pressure data, recorded together with the gravity data, proved useful in ensuring that the density data had the necessary high accuracy. This paper additionally presents modelling results that indicate the potential usefulness of time-lapse borehole gravity data for monitoring floodfronts remote from a borehole. This application would benefit from the development of a sensor with a very reliable absolute calibration and low drift.
Modelling the Performance of High-Pressure High-Temperature Wells
Authors: Baker A. C. , Price M. 
Published: December 2007

SYNOPSIS
Drilling into high pressure high temperature reservoirs gives rise to additional hazards which are not present in more conventional reservoirs. High surface temperatures and pressures may result when reservoir fluids are brought to surface either during production testing or in a well pressure control operation. Accurate estimation of pressure and temperature profiles is required during the well planning stage to ensure that downhole and surface equipment is specified which can meet these criteria. Critical temperature-sensitive equipment items include the elastomeric seals used in BOP's, valves, wellheads and flexible hoses.
There is also a requirement for the calculation of temperatures downstream of the choke when circulating out a gas-kick under controlled conditions, in order to check for possible cryogenic temperatures and hydrate formation downstream of the choke valve.
While computer simulation models are of great assistance in predicting surface pressures and temperatures, maximum use should also be made of available reservoir fluid data and historical production test data from similar wells in order to test and validate the models. Such an exercise has the dual benefit of highlighting any shortcomings within the models and increasing confidence in further predictive modelling.
Safety for the 90's: A Drilling Contractor's Perspective
Authors: Tait S. , Mumford G. 
Published: December 2007

ABSTRACT
In the aftermath of several highly publicised events in the North Sea a drilling contractor has taken a fresh look at their safety programme. It was decided to concentrate on making it an employee oriented programme with the key element being commitment from the rig personnel. At the end of 1989 their lost time injury frequency rate had improved by over 30% in spite of increased activity and high turnover in all sectors of North Sea industry and a corresponding decrease in the level of experienced personnel in many positions. This paper describes the steps taken in this programme, their results and how they will be followed up in the 1990's.
Economics of Gas Conversion Projects in the North Sea and Barents Sea
Authors: Antia D. D. J. , Seddon D. 
Published: December 2007

ABSTRACT
Different processes, costings and economics for the development of marginal and giant offshore gas fields, as synthetic fuel and commodity chemical producers are evaluated. The processes have become economic as a result of improved process design, modularised construction techniques, targeted high value added finished products (e.g: methanol, unleaded gasoline, waxes, etc.), new catalyst technology, and process technology.
Practical Application of Computer Technology to Petroleum and Gas Operations
Authors: Gaffney P.D. 
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers Inc.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
Detailed reservoir calculations, large-scale pipeline design and many refining operations now are carried out with the use of computer techniques. However, routine handling of small projects such as the calculation of oil and gas reserves, the evaluation of pressure buildup data for production and reservoir applications, etc., continues to be done to a large extent by manual techniques.
This paper discusses the considerable potential for the operations engineer in using potential for the operations engineer in using both the results of simple data processing and the new small scientific computer. It is concluded that valuable improvements in the use of technical manpower would result from a greater understanding and application of these modern techniques.

Introduction
The application of computers and data processing to the solution of technical processing to the solution of technical problems for the petroleum industry has seen great problems for the petroleum industry has seen great progress in recent years. However, in many progress in recent years. However, in many respects, this application has been limited to the more mathematically inclined and to those engineering problems involving detailed repetitive solutions such as process and reservoir engineering calculations. The application of these techniques to the day-today engineering problems besetting the individual field problems besetting the individual field engineer has not yet been universally accepted. This paper examines these applications in the light of more recent computer and data processing developments, and illustrates the processing developments, and illustrates the advantages of applying such techniques to routine daily problems.

DEFINITIONS
"Data processing" in this context refers to all machine processing that requires simple multiplication, division, addition and subtraction and the carrying of totals. These tasks need relatively uncomplicated sorting machines, printers, card readers, punches and a small printers, card readers, punches and a small arithmetic unit. A "computer", on the other hand, refers here to a processing machine that has considerable memory [storage] capacity and can perform calculations much faster than the simple data processing machine. However, while in many cases data processing problems are carried out on computers because of their greater capacity, it is rarely possible to reverse this and solve even simple engineering problems on data processing equipment. problems on data processing equipment.
Economics of U.K. Field Abandonment
Authors: Antia D. D. J. 
Published: December 2007

ABSTRACT
The financial risks associated with UK field abandonment are identified. Different risk minimisation and value enhancement strategies for the abandonment of UK fields are discussed. They include facility reuse, abandonment deferral, insurance, turnkey production leases, sale and leaseback, divestment, acreage-production swaps, and crossfield offsets. The adoption of an appropriate abandonment strategy can significantly reduce the after-tax cost of abandonment.
Comparison of Deterministic and Probabilistic Simulation Models of Channel Sands in the Statfjord Reservoir, Brent Field
Authors: Keijzer J. H. , Kortekaas T. F. M. 
Published: December 2007

ABSTRACT
The Brent Field has an estimated STOIIP of 3,440 MMstb and a GIIP of 6.9 Tscf. The field is operated by Shell on behalf of a Shell – Esso joint venture. It consists of two separate reservoirs, the Brent and Statfjord reservoir. Both reservoirs contain light oil, overlain by condensate rich primary gas caps. Definition of an optimal long-term development plan for the Brent Field required the construction and application of the so-called Brent Full Field Simulation Model. A key issue in the construction of reservoir simulation models of the field is the description of the reservoir geology. The description of channel dominated sands in the Statfjord reservoir was anticipated to pose major difficulties in the history matching process. Therefore, the merits of using more detailed geological models, in particular probabilistic models, were investigated. Well data were used to generate three probabilistic models of the geological most complex middle reservoir units of a part of the Statfjord reservoir. To incorporate vertical crossflow, these models were embedded between the deterministically modelled over- and underlying reservoir units. Extensive software was developed to translate the extremely detailed models (&gt;150,000 blocks) into coarser simulation models. To allow for a valid comparison between the probabilistic approach and the conventional deterministic approach, a completely conventional model with identical grid definition was built for the same part of the reservoir.
Simulation of the displacement characteristics revealed that the incorporation of the more detailed geology led to a substantially improved description of the historical well performances. The implicit definition of shales in the probabilistic models proved to be an important characteristic: the production performance in the over- and underlying non-probabiiistically modelled layers was significantly affected by the inclusion of the detailed geology in the probabilistically modelled layers.
In view of the promising results, the use of more detailed geological models in future generations of the Brent Full Field Simulation Model is being reviewed.
Evaluation of Capacity and Gas Yield of Low-Porous and Low-Permeable Reservoirs
Authors: Teumer P. , Voight H. D. 
Published: December 2007

ABSTRACT
Significant gas reserves are accumulated in "tight" gas sands in the German Democratic Republic (Eastern Germany). This potential mainly occurs in layers that form the overlying and underlaying sections of higher permeable payzones. In order to etablish the development of the resevoir in such way, that maximal gas yield and production are achieved the following extensive investigations were carried out:
– degasification and pore size measurements, – porosity mesurements in dependence confining pressure, – special drillstem tests (DST), – pressure buildup behaviour in layered reservoirs, – estimation of the gas recovery factor, – material balance behaviour in layered reservoirs.
The objective of this paper is to report the results of this investigations.
Planning, Implementation, and Analysis of the First Troll Horizontal Well Test
Authors: Hovland S. , Jones C. , Whittle T. 
Published: December 2007

ABSTRACT
Details are given of the design, implementation and analysis of the initial well testing and production logging of a horizontal well recently drilled in the North Sea. Test rates of 2000 Sm3/d of oil were measured with a drawdown of 0.26 bar producing through a wire wrapped pre-packed screen. The production log verified the majority of the well to be producing and, with the aid of a type curve presented here, the pressure build-up analysis yielded the effective vertical permeability of the reservoir.
The test confirmed the suitability of the well for long-term testing during which stable liquid rates of 5000 Sm3/d have been produced.
Performance of Slanted and Horizontal Wells on an Anisotropic Medium
Authors: Besson J. 
Published: December 2007

ABSTRACT
Although the technology of highly inclined and horizontal wells has recently progressed significantly, a reliable and practical formula to estimate the productivity of the well with respect to any angle of slant and anisotropy of permeability is still missing. This paper provides a method of estimation which fills the gap.
The well pressure decline curves are generated by a semi-analytical in-house simulator. They lead to a geometrical pseudo skin factor which is matched for slanted wells with an analytically-derived equation. For horizontal wells, comparison is made with several existing formulae.
An unrestrictive approach of anisotropy is possible through a spatial transformation from real medium into equivalent isotropic medium : this is achieved by modifying the length, azimuth, inclination and radius of the well. Equations of the pseudo skin factor are modified according to this transformation.
Calculations reveal that a slanted well is less affected by anisotropy than a horizontal well : with a low vertical permeability, it can be more advantageous than a horizontal well of the same length. Graphic charts are displayed to easy the choice between horizontal and highly inclined wells.
Placing Proppant in a Naturally Fractured Reservoir With Unconventional Leakoff: A Field Case
Authors: Cuesta J. F. , Markland J. T. 
Published: December 2007

ABSTRACT
A proppant placement experiment was carried out in February 1989 at the Rosemanowes Research Site in Cornwall, England. The experiment was designed to produce a stimulated region of at least 50 m radial extent when viewed along the RH15 production wellbore. This was believed to be the extent of a high impedance zone around RH15 identified from microseismicity induced during previous circulating, with RH15 as the production well.
The location of the stimulation interval within the wellbore was constrained by wellbore and reservoir considerations. After analysis of the mini-frac, originally intended to optimise the main-frac pumping schedule, a conservative approach was taken to the design of the proppant placement operation. The proppant was placed using a high viscosity non-linear gel.
Consideration of both mini-frac and main-frac operations along with evidence from diagnostic tools suggests that the ‘fracture’ initially grew radially with subsequent substantial confined extension. Fracture growth is inferred to have developed from a single point exit in RH15 at a previously existing flowing joint, and extended into a region of previously observed microseismicity. No wellbore damage was incurred. It is presumed that previous stimulations within the rock mass and thermal contraction resulting from prolonged reservoir circulation were controlling factors in fracture growth.
The experiment successfully demonstrated the concept of proppant placement in a naturally fractured igneous reservoir.
Development of Small Concrete Structures for Safe, Economical Production
Authors: Gudmestad O. T. , Stead B. 
Published: December 2007

ABSTRACT
The interest in concrete structures is presently gaining much attention. This interest is caused by the designers offering optimized structures answering the need to stimulate marginal field developments. Furthermore, the use of high strength concrete, the low installation costs for concrete structures and the need for competition in the platform construction market have enhanced the interest in concrete structures.
Small concrete structures are being studied for several applications both as wellhead platforms and small wellhead/process platforms often combined with storage facilities.
The paper describes recent development towards optimized small concrete structures for safe, economical production. The following items are in particular highlighted: The design process, concrete material aspects and the importance of the fabrication and installation procedures. Furthermore, the safety of the structures in the fabrication and installation phases are discussed in view of the need to secure the investments.
Requirements to secure competitive structures and safe operations are furthermore being reviewed and examples of interesting small concrete solutions are shown.
This paper can be seen as a guidance note related to design of safe economical small concrete structures.
Scaling Relationships in Natural Fractures: Data, Theory, and Application
Authors: Heffer K. J. , Bevan T. G. 
Published: December 2007

ABSTRACT
Length frequency distributions of fractures are shown to have a power-law trend across many orders of magnitude. This allows an estimate to be made of the full number of fractures and faults existing in a reservoir over that which can be measured from core and seismic data. This relationship has been applied to reservoir studies involving the continuity of juxtaposed sands, permeability impairment, and estimating the number of fractures that a horizontal well may intersect.
Many more fractures and faults exist in reservoirs than those that can be observed from seismic and core data, which have significant implications for reservoir characterisation, geomechanical properties and waterflood behaviour.
Gas Condensate Flow Through Chokes
Authors: Osman Mohammed E. , Dokla Mahmoud E. 
Published: December 2007

ABSTRACT
In this study, field data from a gas condensate reservoir located in the Middle East are used to develop some empiricial correlations that describe the behaviour of gas condensate flow through chokes. The data cover wide ranges of flow rates and choke sizes. Four forms of correlation are checked against data. One of the forms is to correlate choke upstream pressure with liquid production rate, gas liquid ratio and choke size. The second form is developed by using gas production rate instead of the liquid rate in the previous form. The other two forms are developed by using the pressure drop across the choke instead of upstream pressure. These correlations are presented in graphical forms. Five error parameters are used to check accuracy of the different forms. Namely: root mean square error, mean absolute error, simple mean error, mean percentage absolute error and mean percentage error. It was found that the correlation is most accurate when using pressure drop data instead of choke upstream pressure in the correlation. The importance of the developed correlations lies in the fact that correlations for gas-condensate systems are not available. Also such correlations will help the production engineer to a great extent in selecting choke sizes to control production of gas-condensate wells and predicting the performance of flowing wells under different conditions.
The Leman F aand G Development: Obtaining Commercial Production Rates From a Tight Gas Reservoir
Authors: Clayton F. M. , Gordon N. C. 
Published: December 2007

ABSTRACT
The Leman F/G development was undertaken to drain the relatively undepleted and poor reservoir quality North Western area of the Leman field and massive hydraulic fracturing is required to achieve commercial production rates.
Two jackets were installed in December 1985 and the first fourteen wells were successfully stimulated and brought on stream on schedule by 1st October 1987. Initial production rates of between 5 and 40 MMscf/d per well were achieved. Further wells were drilled and stimulated in 1988 and 1989. The changes implemented in the design and execution of the treatments during these campaigns are explained and the results compared with the original wells.
The paper outlines the organisation and execution of the programmes of perforation and stimulation followed by clean out with coiled tubing and clean up of these twenty two wells. In total, some 10 million lbs of proppant were placed. The integrated planning required to complete a successful offshore fracturing campaign on a tight schedule is highlighted.
The problems encountered with back production of proppant both during initial production and over the longer term are discussed, as are the measures implemented and under consideration to mitigate future problems.
Results from a Horizontal Well in a Rotliegendes Gas Field
Authors: Hawkings N. , Ramsey C. , Rapach J. , Kristof M. 
Published: December 2007

ABSTRACT
The North Valiant gas field in the Southern North Sea yielded disappointing results during initial development drilling due to the failure of development wells to locate the high permeability dune sands encountered during field appraisal. In order to achieve a better chance of locating these sands in a thin (+/-150′) reservoir it was decided to drill a 2000′ horizontal well. This was the first horizontal well to be drilled in the UK Gas Basin and the first in the UK to use medium radius drilling techniques. The well was successfully drilled, logged, completed and tested and is now on production. The well achieved the best deliverability of any North Valiant well, with a Productivity Index (P.l.) double that of the nearby exploration well. It has doubled the field's available deliverability. The well cost approximately the same as a fracture-stimulated conventional development well.
New Latex, Expanding Thixotropic Cement Systems Improve Job Performance and Reduce Costs
Authors: Jones R. R. , Carpenter R. B. 
Published: December 2007

Abstract
A unique cementing system is presented which provides improved cement bonding and zonal isolation in wells having bottom hole static temperatures (BHST) below 175° F. Selectively formulated with components common to the industry, this system is reliable and versatile.
Latex cement additives are excellent bonding aids, gas migration preventers, matrix intensifiers and fluid loss additives. They improve cement's elasticity and resistance to corrosive fluids. Thixotropic, expanding cements excel in providing annular fill, zonal isolation and lost circulation control. Combining these two technologies into a single, efficient, low cost system has provided technical and economic properties which have had significant impact on cementing operations. This new cementing system is hereafter referred to as LXT for latex, expanding, thixotropic cement.
The properties engineered into the LXT system provide better primary and remedial cementing applications through: (1) reduced invasion of permeable, unconsolidated or "weak" zones by whole cement or cement filtrate, (2) prevention of gas or fluid migration in hydrating cement columns, (3) greater zonal isolation between differentially pressured intervals separated by thin, shale barriers, and (4) rapid compressive strength development and minimal waiting-on-cement (WOC) time. Laboratory studies and case histories are presented to show the merits of this cement system over conventional low water loss (LWL) systems. Numerous applications in East Texas, West Texas (Permian Basin) and on the West Coast have resulted in marked improvements in job quality and success rates over prior cementing practices.
Thermal Alteration of Medium and Heavy Compounds of Crude Oils by Pyrolysis and Combustion
Authors: Pusch G. , Ranjbar-Hamghawandi M. 
Published: December 2007

Abstract
Polymerization induced by radicals may convert normal alkanes into resins or waxy compounds between 300°C and 450°C and resins into asphaltenes at temperatures above 450°C. The nature of this chemical conversion was studied by the use of extracted model compounds and of natural crude oils during isothermal and constantheating rate pyrolysis. A thin bed reactor made from sinter glass which represents the properties of the porous medium was used.
Results of the study show that in the temperature region below 450°C the amount of resins in the crude oils determines the reaction rate of combustion, whereas above 500°C the amount of aspaltenes dominates the reaction rate constant. This tendency was observed with model substances as well as with dead oils, independently of the analytical method applied. Consequently, a large variety of different crude oils from paraffinic light oils to asphaltenic oils is able to produce the required fuel for in situ combustion, provided that the pyrolysis temperature is kept within certain limits. Temperature control in the process is achieved by a variation of the water-oxygen ratio of the injected fluids.
The Thermodynamics of Scale Prediction
Authors: Atkinson G. , Raju K. , Howell R. D. 
Published: December 2007

AbstractA program has been developed for the prediction of sulfate scale formation in single waters or mixtures. The program considers the effect of pressure, temperature, and brine composition using classical thermodynamics and modem electrolyte theory. The important effect of [MgS04°] ion pairing is considered explicitly. All possible sulfate scales are considered simultaneously. This is a far sounder theoretical approach than the sequential approach used previously.