bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Planning and Control of Offshore Hook-up and Commissioning
Authors: Claridge John 
Published: December 2007

ABSTRACT
Hook-up and commissioning is a critical phase in the successful development of an offshore oil production platform, and one where the particular problems of carrying out major works at a remote offshore location make good planning and control very difficult to achieve. This paper describes a general approach to planning and control which is aimed at overcoming these problems. How best to set up the organisation and management is considered, a planning method is outlined, and the major factors which influence the control of cost and schedule are discussed.
Auk Lower Zechstein—Drainage Mechanism Model
Authors: Tosdevin Michael A. 
Published: December 2007

ABSTRACT
By modelling a fractured carbonate reservoir as being composed of a highly permeable fracture zone and a greatly less permeable section representing the matrix it has been possible to match the historical water cut performance exhibited by wells completed in the Lower Zechstein formation of the áuk field. The model was developed as a cross-section to match the water cut of a single well and subsequently extended to three dimensions to obtain a history match of water cut in the seven wells drilled in the area to date.
Once a satisfactory history natch had been obtained the model was run until 1988 to predict future water cut behaviour and to estimate field ultimate recovery.
Applicability of Tailored Pulse Loading for Gas Well Stimulation
Authors: Keough D. D. , Curran D. R. , McHugh S. L. 
Published: December 2007

ABSTRACT
Tailored-pulse loading is a gas well stimulation technique that is promising for particular situations. The key factor in determining the probability of success is the interaction of the loading history with the material properties and in situ stresses of the geologic formation. On the basis of theoretical and experimental studies, tailored-pulse loading is expected to be successful if (a) the rock is fairly competent, (b) the yield stress is greater than about 100 MPa, (c) the overburden pressure is less than about 100 MPa, (d) the natural fracture or joint spacing is less than several meters.
Multiple Fracture Stimulation Using Controlled Pulse Pressurization
Authors: Hanson J. M. , Schmidt R. A. , Cooley C. H. , Schatz J. F. 
Published: December 2007

ABSTRACT
Tight oil and gas reservoirs often require stimulation in order to make economic exploitation possible. Tailored pulse loading, usually by downhole use of propellants or explosives, has been studied as a means of improving production in these reservoirs. This paper presents an overview of the first year's effort on a three-year combined theoretical-experimental research program to develop a systematic understanding of the tailored pulse loading/fracturing phenomena. The project is designed to address the sensitivity of multiple fracture initiation and propagation to rock and fluid properties and pressurization history. The results will ultimately contribute to the design procedures for field applications.
Cavity Stress Relief Method To Stimulate Demethanation Boreholes
Authors: Alain A. K. , Denes G. M. 
Published: December 2007

ABSTRACT
Most demethanation programs which use boreholes from the surface to access the coal, incorporate a stimulation program to enhance the well production. In most cases, the stimulation selected is a frac using nitrogen foam or other fluids. Novacorp has determined that fracing the coal may not be the best technique to apply to a well.
Novacorp, whose experience includes over eighteen (18) fracs on demethanation wells, has developed and patented an alternative stimulation method, called the Cavity Stress Relief (CSR) technique, which it believes is more effective than the frac, in most cases.
Through a review of the basic parameters which affect the desorbtion of gas from coal, a comparison is made between the frac and CSR stimulation techniques. A description of the conditions and results of two field tests of CSR are given. Also, the areas which need further development will be discussed. Although still not totally proven, the CSR stimulation technique promises to be a very effective method of stimulating most demethanation wells.
Estimating Formation Permeability From Single-Point Flow Data
Authors: Lee W. J. , Kuo T. B. , Holditch S. A. , McVay D. A. 
Published: December 2007

ABSTRACT
Many operators do not routinely run pre-stimulation pressure buildup tests in low permeability gas reservoirs. Frequently, all that is available is a single-rate flow test. To obtain permeability estimates for FERC filings and to evaluate the reservoir, a new method has been developed for analyzing typical pre-fracture production data.
Permeability estimates obtained from this method have been used as a major source of data in numerous successful tight gas determinations, including the Cotton Valley, Wilcox Lobo, and Canyon formations in Texas.
The paper shows that this simple method can be quite reliable. This conclusion is based on a comparison of permeabilities estimated with this technique and with more rigorous determinations from pressure buildup tests.
An Ultrasonic Borehole Flowmeter for Production Characterization of Eastern Shale Gas Reservoir
Authors: Semmens M. G. , Tausch H. J. , Ondrik M. A. 
Published: December 2007

ABSTRACT
A gas borehole flowmeter providing high resolution flow measurement is being developed to support natural gas production enhancement research within the United States Eastern Devonian Shale. The flowmeter utilizes ultrasonic technology which will provide excellent resolution and measurement accuracy. Early developmental test data indicate that the tool will be able to measure very low flow rates produced by borehole gas entry before fracture, i.e., .009 dm3/s (0.02 cfm). The use of time-of-flight dual transceivers will provide accurate gas velocity and flow measurements previously unavailable.
Liquid Permeability of Coal as a Function of Net Stress
Authors: Rose R. E. , Foh S. E. 
Published: December 2007

ABSTRACT
Coalbed methane production is initiated by the removal of formation water in quantities sufficient to accomplish a large reduction of fluid pressure in the cleat system. Pressure reduction causes gas to be desorbed from the coal; the cleat system channels this gas to the wellbore. The rate and quantity of water removal is limited by permeability of the cleat system which is usually stimulated to facilitate dewatering and gas production.
Experiments were performed at IGT under in-situ conditions on coal from five U.S. basins. Results showed that water permeability of a given sample decreased by as much as two orders of magnitude over pressure ranges that simulated normal dewatering and production cycles.
Knowledge of the behavior of permeability as a function of net stress allows a better understanding of the following realities of coalbed stimulation: 1) a horizontal drill hole of a given length is much more productive than a propped fracture of the same length; 2) in general, fractures induced in coalbeds are much shorter and wider than designed; and, 3) frac pressures in coalbeds are abnormally high — significantly above overburden in many cases.
Other consequences of a permeability-net stress functionality include: 1) skin factor determinations from injection tests are necessarily more optimistic than those based on drawdown data; 2) overbalanced drilling increases the invasion radius of drilling fluid filtrate, thereby creating the potential for more extensive formation damage than in conventional reservoirs; and, 3) leakoff during fracturing operations is significantly higher than for "conventional" sandstone or limestone beds having identical pre-injection permeabilities.
Use of a Computer Model To Design Optimal Wellfields for Dewatering Coal Seams for Methane Production
Authors: Bumb A. C. , McKee C. R. 
Published: December 2007

ABSTRACT
A model is presented for optimizing the number and locations of wells for various hydrologie and reservoir conditions. It can handle confined or unconfined aquifers, leaky or non-leaky aquifers, isotropic or anisotropic permeabilities, existing wells at fixed or model-determined optimal flow rates, complex boundaries, and specified regions to be excluded from possible well location sites for environmental or other reasons.
Examples demonstrate that optimum wellfield design differs significantly from the patterns widely used in the gas industry. Optimum patterns depend heavily on the reservoir and hydrologie characteristics of the target, the shape of the project site, existing wells, the total number of wells, and water pressure drop in the coal seam required to commence gas flow.
Practical Methods for Detecting Production Mechanisms in Tight Gas Reservoirs
Authors: Ammer J. R. , Sawyer W. K. , Drophin M. J. 
Published: December 2007

ABSTRACT
A recent study has been conducted on the "Clinton" sandstone of Ohio by the U.S. Department of Energy. The purpose of the study was to identify production mechanisms as related to the geometry of the "Clinton" sandstone. The theory behind the study was that a log-log plot of cumulative production versus time is indicative of the flow behavior in the reservoir. A 0.50 slope would indicate linear flow exists while a slope of about 0.90 would indicate radial flow exists.
Data from 284 producing "Clinton" gas wells from six counties in eastern Ohio were used in this study. Log-log plots of cumulative production versus time were generated and then the slope values were contoured so that a comparison could be made with regional geological parameters. The results of the study showed that the production mechanisms in the four regions are causing a linear to "intermediate" (between linear and radial) flow. Radial flow was exhibited in wells where the "Red Clinton" was better defined on the gamma ray log, suggesting an offshore bar or shoal. Linear flow was exhibited in wells where the "White Clinton" was more well developed suggesting channel or distributary bars.
The intent of this paper is to make available to industry a practical approach to analyze the performance of past production. This knowledge can be used to gain insight to the factors affecting recovery so that an approach to improvements can be made.
Enhanced Production From a Slightly Geopressured Water-Drive Gas Condensate Field
Authors: Anderson L. L. , Peterson K. P. , Parisi W. A. 
Published: December 2007

ABSTRACT
The production history of a Texas Gulf Coast Frio water drive gas field is presented, including performance data from a well which was recently restored to commercial production after having been abandoned six years. Areas of additional study which would help forecast future performance are discussed.
Negative Decline Curves of Coalbed Degasification Wells
Authors: Harrison G. C. , Gordon R. B. 
Published: December 2007

ABSTRACT
Production data from coalbed degasification wells characteristically exhibit a negative decline curve. The dynamics of this methane production are complex and interrelated. As production begins, water and free gas are often first recovered. Continued production lowers pressure and increases permeability to gas, allowing adsorbed gas to flow. This pressure drop within the formation causes sublimation whereby gas, which is absorbed within the coal, forms on the walls of the micropores. Finally, the desorption through production disturbs the chemical and physical equilibrium of the coal, thus enabling the coal to resume generation of methane.
Evaluation of the Influence of In-Situ Reservoir Conditions on the Geometry of Hydraulic Fractures Using a 3-D Simulator: Part 2—Case Studies
Authors: Abou-Sayed A. S. , Clifton R. J. , Dougherty R. L. , Morales R. H. 
Published: December 2007

ABSTRACT
The development of the basic theory and numerical implementation of a three-dimensional hydraulic fracturing simulator has been completed. The description of the model is being presented in two companion papers. The first paper (Part 1) discusses the analytical elements of the theory, while this paper considers the practical applications. The simulator can predict fracture geometry in a layered rock media under a wide range of in situ and fluid treatment conditions.
A total of 15 cases are discussed. The effects of fracture pressure gradient, stress contrast, reservoir layer stiffness, fluid viscosity and initial fracture geometry are evaluated. Resultant fracture shapes are presented and their implications on fracture design are discussed. Fracture containment is shown to be strongly dependent on the elastic modulus of the formation, magnitude of stress barriers, and fluid viscosity.
New BallaSet Diamond Bit Proves Effective for Drilling Twincreek Limestone and Nugget Sandstones in the Overthrust Belt
Authors: Ivie C. R. , Wood J. E. 
Published: December 2007

ABSTRACT
Early in 1984 a new type of synthetic diamond drill bit war, introduced. The bits, know as ballaset diamond bits, are designed for and work well in medium to hard, moderately abrasive formations such as limestones, dolomites, hard brittle shales, and sandstones. Two years of field tests, many in the overthrust belt, have proven that ballaset diamond bits offer faster rates of penetration, longer life on bottom and overall improved performance when compared to types 3, 4, 5, and 7; tungsten carbide insert bits in mediun to hard formations like the Twincreek limestone and Nugget sandstones of the Overthrust Belt.
The ballaset cutting elements are polycrystalline, synthetic diamond. They differ from other polycrystalline synthetic diamonds (diamond compact) such as General Electric's Stratapax, in that they are thermally stable up to 1200°C. Other synthetic diamonds are thermally stable up to 800°C. Recognizing that frictional wear is a major factor limiting the hardness and abrasiveness of diamond compact drillable formations, thermally stable ballaset diamond bits can now drill these formations.
The Rocky Mountain Overthrust Belt, particularly the areas around Evanston, Wyoming and Duchesne, Utah, offer a wide variety of medium to hard moderately abrasive formations such as the Twincreek limestone, Tensleep sandstone/anyhdrite, Nugget sandstone, Madison dolomite and Gannet sandstones. Case histories illustrating runs in these formations are included.
Several runs with ballaset diamond bits have been made. Many runs were economical, and some formations tested were too abrasive and some were too soft. Therefore, application selection is important in the successful economic use of ballaset diamond bits. TwincreekCase HistoriesSizeStyleWOBRPMFeetHoursROP6 1/4″S248545073181.59.08 1/2″S24815400466528.88 1/2″S2483Motor7071007.1Nugget6 1/4″S2481040024128.58.56 1/4″S2481640021232.56.5
The successful runs of ballaset diamond bits in the Rocky Mountain Overthrust Belt, particularly in Twincreek limestones and Nugget sandstones have demonstrated economical advantages. Increased performance and cost reductions in other areas will be possible by careful application of these bits.
The Effect of Filtrate Invasion and Formation Wettability on Repeat Formation Tester Measurements
Authors: Phelps G. D. , Stewart G. , Peden J. M. 
Published: December 2007

ABSTRACT
This study addresses some of the problems (conceptual and practical) associated with the Repeat Formation Tester (RFT)* tool. It is shown that although the RFT detects the filtrate phase pressure at the sandface, this may differ from the oil phase pressure in the undisturbed formation as a result of capillary interface effects, formation wettability effects and supercharging (the pressure superimposed on theinitial formation pressure as a result of the viscous flow of filtrate).
It is shown that whilst capillary driven flow may be significant in high permeability formations, the effect of capillary gradients in low permeability formations may be neglected and the Buckley-Leverett immiscible displacement equation used to model the invasion process.From this basis a modified theory of supercharging is developed. The theory recognises that supercharging can be a two phase problem and that the difference between the invaded and uninvaded zone mobilities should be taken into account. It is found that depending on the stability of the displacement, supercharging in a hydrocarbon zone can be enhanced or reduced by the presence of mud filtrate.
A field example is analysed in an attempt to validate the proposed theory, as well as to demonstrate how an estimate of the downhole static filtration rate may be determined from RFT measurements.
Consideration of formation wettability characteristics leads to the conclusion that most formations possess some degree of mixed wettability and that consequently the free water level (FWL) should lie above the oil-water contact (OWC). It is suggested that if such a reservoir were analysed on the assumption that it was water wet, then the reversal of the FWL and OWC from the water wet case would probably notbe observed. In addition the estimated formation pressure would be too high and the estimated FWL to low.
Some Well Test Analysis Results For A North Sea Oil Well
Authors: Wilson Mike R. 
Published: December 2007

ABSTRACT
With modern computing capabilities, well test interpretation has evolved from simple straight-line techniques to a methodical interpretaion process making use of a variety of analysis procedures and complex well models. These analysis procedures range from engineering methodology to computer automation. Regardless of which procedure is used, however, there is a fundamental limit to the amount of information that can be extracted from a given well-test. This limit can only be overcome by using information obtained from other sources.
This paper uses a general buildup analysis procedure suggested by A.C. Gringarten as a framework to present an argument as to why there is a limit. The analysis procedure is based on three steps making a diagnostic plot of the data to select a well model, fitting the model to the data, and checking the fit for consistency with all the pressure data. The central point in the argument is if a well model matches a buildup and yields a correct pressure at infinite shut-in time, the model will be found to be consistent with all the pressure data. This results in two limitations which state when all consistency checks are not necessary and when well models cannot be distinguished from one another.
The results from the analysis of a North Sea oil well are presented to illustrate these limitations to well test interpretation. This analysis shows a comparison of results for two diferent bounded reservoir well models and a double-porosity model. Two of the models yield equally good matches of the buildup and drawdown data. Only by using other information about the well and reservoir could a choice be made between the two.
Completion of the Claymore Gas-Lift Optimisation Project
Authors: McAllan J. L. 
Published: December 2007

Abstract
This is a case history of an innovative process, thatof a gas lift optimisation supervisory system, currently in operation on Occidental's Claymore Platform.
It describes the initial arrangement on Claymore, showing why and how the system came into being, what it consists of by way of hardware, and how the offshore operation has benefited as a result of the project.
Weight Control: A Growing Awareness
Authors: Elleston F. G. 
Published: December 2007

ABSTRACT
Since the mid-1970's the subject of weight control has, increasingly, become accepted as a necessary part of offshore projects. Gradually, weight control systems have been developed and improved, and awareness of the subject is definitely growing.
Little by little, design and fabrication contractors, client companies, and finally, government agencies, are learning the trade.
The first published article on the subject was in October 1978 (1), but, since that time numerous articles have followed, and a number of international seminars have been convened (2).
An Integrated Computerised Maintenance System for Offshore operations
Authors: Logan W. A. , Hasell B. H. , Trussell P. 
Published: December 2007

ABSTRACT
This paper reviews the evolution of a mainly manually operated maintenance, warehouse and purchasing system for the Mobil North Sea Limited ('Mobil') operated Beryl field inthe U.K. North Sea and gives the strategy of a transition toward an on-line computerised systemcalled MIMICS (Mobil Integrated Maintenance and Control System).
A New Concept in Floating Production Systems
Authors: Patel M. H. , Montgomery J. I. , Worley M. S. 
Published: December 2007

ABSTRACT
This paper describes a tandem hull floating production platform which combines the large deck space and high payload carrying advantages of a monohull vessel with some of the low wave induced motion characteristics that are typical of semisubmersible vessels. The basic features of the tandem hull platform are presented and comparisons made with the motion characteristics of various other hullforms. The model tests and computer simulation programs used in the design of the tandem hull platform are described and the results presented. Assessments are made of the capital and operating costs of a tandem hull production system and comparisons made with those of other floating production systems that are based on alternative hull forms.
The First Purpose-Built Stimulation Vessel for North Sea Application
Authors: Cooper R. E. , Marshall L. B. 
Published: December 2007

ABSTRACT
A purpose-built, well-stimulation vessel has just been put into service in the North Sea. Previous limitations of existing converted supply-boats need no longer inhibit North Sea stimulation technology. Described is the evolution of this vessel, the design criteria selected for its marine and stimulation capabilities, and details of en-visaged future typical well-stimulation treatments.
Cavity and Gravel-Pack Logging in Groningen Gas Wells A Progress Report
Authors: Strobl W. , Plackett W. G. 
Published: December 2007

ABSTRACT
Various logging tools have been tested in the Groningen gas field to: .Determine thepresence, size andshape of cavities behind perforated production casings caused by formation sand production..Evaluate the success and quality of gravel packing operations.
Cavities can be detected, but extensionfrom the borehole cannot be quantified.
In gravel packs, gravel tops, pack density, failures, etc. can be evaluated qualitatively.
The Role of Taxation in Optimising the Exploitation of the U.K. Continental Shelf
Authors: Underdown D. J. 
Published: December 2007

ABSTRACT
The UK Government has already shown itself responsive to the need to adapt the structure of taxes on offshore oil to meet the changing economics and patterns of activity which can be expected as the UKCS matures.
A gradual modification and relaxation of the UKCS tax regime should be seen as a vital ingredient in policies to ensure that the full hydrocarbon potential of the UK offshore is realised.
GEODYN: A Geological Formation/Drillstring Dynamics Computer Program
Authors: Baird J. A. , Caskey B. C. , Tinianow M. A. , Stone C. M. 
Published: December 2007

ABSTRACT
This paper describes the initial development phase of a finite element computer program, GEODYN, capable of simulating the three-dimensional transient dynamic response of a polycrystalline diamond compact (PDC) bit interacting with a non-uniform formation. The ability of GEODYN to simulate response variations attributable to hole size, hole bottom surface shapes, and formation material non-uniformities is demonstrated. Planned developmental phases will address the detailed response of a bottom-hole assembly (BHA), a drill ahead (rock penetration and removal) simulation, and ultimately, the response of the entire string.