bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the Influence of In-Situ Reservoir Conditions on the Geometry of Hydraulic Fractures Using a 3D Simulator
Authors: Dougherty R. L. , Abou-Sayed A. S.
Published: December 2007

The effectiveness of hydraulic fracturing in most applications is directly dependent upon the geometry of fractures created within the layered reservoir[l,2]. Therefore, design of fracturing treatments is generally based on maximizing fracture length and propped width (conductivity) while maintaining fracture height as close to pay zone height as possible [c.f. 3, 4]. In certain situations, such as the proximity of the pay zone to a water aquifer, vertical fracture extension could become critical. Hence, fracture geometry calculations that do not assume a constant fracture height have become necessary requirements for optimum treatment design.

This paper discusses a three-dimensional model, "HYFRAC", and shows its applicability to fracture geometry prediction for a wide variety of conditions. The results of the 3-D fracture analysis can be employed to validate and/or evaluate currently used models and theories of fracture growth. Comparisons will be made with Perkins and Kern predictions of constant height growth [5], with Geertsma-DeKlerk[6] and with methods using downhole pressure variation to determine fracture growth and stability[7]. Results from other current models will also be compared to HYFRAC results. Such studies will help determine the strengths and weaknesses of the available models. This will provide a better understanding of when problems require a fully three-dimensional solution and when a two-dimensional, quasithree-dimensional, or other analysis may suffice.
3D Analytical Model for Hydraulic Fracturing: Theory and Field Test
Authors: Bouteca M. J.
Published: December 2007

A fully 3-D analytical model of hydraulic fracture propagation is proposed which can be used to determine both the least in situ stress and the fracture height if the pressure is recorded as a function of time. A field test is presented where the values of in situ least principal stress and height calculated by the model could be compared with in situ stress measured by shut-in pressure test and with fracture height estimated by acoustic emission analysis.

It is also shown that stress variation with depth and any pressure drop law in the fracture can be simulated by modifying boundary conditions on the fracture surface.
Demand For Petroleum Engineers An Analysis Of The Society Of Petroleum Engineers 1984 Manpower Survey Data
Authors: Calhoun John C.
Published: December 2007

Calhoun Jr., John C.,Returns were received from 22 companies with data sufficiently complete for comparative analysis. Twelve companies, reporting 400 or more engineers employed at year-end 1983, will be called Group I. Seven companies, reporting engineers employed at year-end 1983 in the 40 to 115 interval, are designated Group II, and three companies with 10 or less engineers employed at year-end 1983 are Group III. The total population of employed engineers and petroleum engineers represented at year-end 1983 are shown in Table I.Total engineers employed by these reporting companies reached a peak for year-end 1982, with a decrease of 0.7% to year-end 1983 (see Table II). Projections for year-end 1984 and beyond show- a further five-year decrease of 7.6% on the low side, and a five-year increase of 3.6% on the high side. There is a difference to be noted, however, between those companies with engineering complements over 400 and the other companies. The smaller companies did not report any drop in total engineering work force through 1983 and their five-year projections, even on the low side, show a five-year increase of 5.1%.The petroleum engineering work force reported by these companies did not decline at any point in the five year period 1979–1983, although the increase was only 1.8% for 1983 over 1982 (Table II).
Engineering Manpower Supply and Demand in the Petroleum Industry as Affected by Engineering Salary Trends
Authors: Brown D. C.
Published: December 2007

Prepared for presentation as part of a panel discussion on Petroleum Industry Engineering Manpower Supply and Demand, at the Annual Conference of SPE at Houston September 17, 1984.

To understand the. changes that occur periodically in engineering manpower supply/demand trends in the petroleum industry, it is desirable to have an awareness of some of the major activity factors affecting such trends, of starting Petroleum Engineering salaries relating to that background, of the on-going engineering salary status which developed from these activities, and of the large effect that high starting and on-going salaries do have in attracting and retaining engineers within the petroleum industry.

There is no single entity or group, which by itself sets the climate for engineering manpower trends in the petroleum industry: rather it is set by the interactions of a very large number of companies and individuals, from the diverse and multiple parts of the industry, in creating demand for engineers of the various types and levels needed by their organizations.
Forecasting P.I. and kg/ko Behavior
Authors: Sheldon W.C.
Published: December 2007

Reservoir behavior is usually calculated or predicted on the basis of average values of reservoir characteristics. For reservoirs having wide variations, values calculated from field behavior often are widely different from those determined from laboratory data. Regardless of how data are treated to arrive at average values, the average cannot be used in many cases.

This paper presents a method for forecasting changes in P.I. and calculating kg/ko performance from laboratory data for fields showing wide variations in permeabilities. The resultant kg/ko relations are much more correlative with actual field performance than those where laboratory data are used with simple average reservoir characteristics. Instead of considering the reservoir as homogeneous and taking average values, this method considers the effect of the reservoir heterogeneity. The effect of size of gas cap and rate of gas return (rate of injection) on future P.I. and kg/ko behavior can then be evaluated. Also, a material balance on segments of the reservoir permits evaluation of pressure behavior as a function of rate of depletion with this form of calculation. In order to make comparison of this method with previous efforts, the results have been expressed in terms of the average gas saturation within the reservoir.

Introduction

Two parameters frequently used in reservoir studies are productivity index (P.I.) and kg/ko relationships. They are particularly important when calculating or predicting future reservoir behavior of oil producing reservoirs. Equations have been developed which permit easy calculation of the effect future pressure changes will have upon the P-V-T factors of the future P.I., but these tacitly assume that the relative permeability to oil within the reservoir will remain constant. Actually, these equations are incomplete unless they include terms which will take into account the effect of changing oil saturations. In the past, no adequate way of forecasting relative permeability to oil within the reservoir was available, hence no reliable method had been developed for forecasting P.I. where reservoir saturations would change.

Before permeability to any phase may be developed within a reservoir, the saturation of that phase must be sufficient to establish continuous flow channels. This is the minimum or threshold saturation which must exist before flow can take place. Calculated relative permeabilities or kg/ko ratios for free gas produced from an oil producing reservoir, based upon field performance, result in threshold values which frequently are much below those indicated from laboratory results. This leads to the fact that the second parameter, kg/ko, is also dependent upon relative permeability to oil within the reservoir. Many times, laboratory results fail to agree with kg/ko figures calculated from production data. The relationship between kg/ko and either oil or gas saturation is not linear, but exponential. Therefore, it is difficult, if not impossible, for a single laboratory datum to represent a whole field or a whole reservoir.
VOLAN Interpretation and Application in the Bone Spring Formation (Leonard Series) in Southeastern New Mexico
Authors: Howard A. D. , Fraga J. A.
Published: December 2007

The VOLAN computation, whose name is derived from the words "volumetric analysis," is a new log interpretation technique that uses advanced computer analysis for the evaluation of complex formations. This technique has had successful application in the Bone Spring formation (Leonard series) of southeastern New Mexico.

In complex carbonate deposits where the porosity types include vugs and fractures, conventional log analysis generally has been questionable if only the Sonic log was used. The Sonic measurement tends to overlook the variable degree of secondary porosity inclusive of natural vugs and fractures. The neutron-density tools, on the other hand, measure the total porosity. Thus, to accurately determine values of effective porosity, water saturation, and lithology, the VOLAN program uses the unrefined data from three porosity tools (CNL* compensated neutron, Litho-Density* (LDT), and Sonic) and the resistivity measurements from the Dual Laterolog (DLL*) and Microspherically Focused (MSFL) tools. Positive results with this type of computer analysis have been obtained in the Bone Spring formation where the lithology is complex.

Applications derived from this type of computer analysis are: Identification of potential pay zones by determining the volume of dolomite and degree of secondary porosity.An in-situ formation description using the LDT three-mineral model enhanced by the Sonic measurement.Calculation of an effective water saturation value which has been corrected for the influence of bound water.Correlation with existing logs for mapping.
Rig Preparation for Drilling with Oil-Based Muds
Authors: Carter T. S.
Published: December 2007

Operator requirements for cost effective technical solutions to borehole stability problems have historically been the impetus for new product and mud system development by the industry. Oil-based drilling fluids have long been recognized as a sound technical answer to problems encountered in deep-hot holes and, more recently, to stabilize boreholes with thick intervals of reactive clay formations. However, oil-based mud product development was slowing down until the introduction of low toxicity base oils in the late seventies created a need for new investigations. This innovation sparked a resurgence of oil mud research and development which has resulted in oil-based mud (OBM) systems being used routinely in many active drilling areas worldwide.

Concerns for conservation, both economic and environmental, persist even after low toxicity oils have been accepted, based on field performance, as a suitable diesel replacement. These concerns are important to both the operator and contractor alike. Control of intangible costs related to mud expenditures is important to the operator, but rig modification and installation of auxiliary equipment to process the oil-based drilling fluid are equally important to both companies.

This paper discusses a variety of equipment that is currently available for both onshore and offshore locations to improve oil-based drilling fluid conditioning, to aid oil recovery, to reduce pollution, and to maintain a safe working environment. Minor modification of most of these techniques will allow their utilization on land, inland barge, platform, jack-up, semi or floating drilling units.
A New Approach for Simulating Complex Fractured Reservoirs
Authors: Hill A. C. , Thomas G. W.
Published: December 2007

This paper treats a dual porosity and dual permeability system in which two grids – one each for the fractures and matrix occupy the same volume. We employ 5 pseudo components in the formulation which extends the capability beyond normal blackoil applications. The formulation also permits inert gas injection (i.e. nonhydrocarbon – N2, CO2, etc.) which can diffuse into the liquid phases. Moreover, the oil properties can be optionally treated as functions of pressure and API gravity.

We briefly review the mathematical description of the system. We also describe a memory management scheme whereby one can study large reservoir problems (in excess of 20,000 cells) on computers offering modest core capability. Finally, we present example applications for an isolated fracture system, the effect of cyclic water injection, and the effect of variable API gravity.
Synthesis, Characterization, and Testing of Lignin Graft Copolymers for Use in Drilling Mud Applications
Authors: Meister J. J. , Patil D. R. , Channell H.
Published: December 2007

Partially hydrolyzed poly(lignin-g-(1-amidoethylene)) lowers yield point, lowers gel strength, lowers API filtrate volume, and, after the mud has been hot-rolled at 250°F for 16 hours, functions more effectively as a thinner and agent to control filtration loss than does an equal concentration of chrome lignosulfonate in a water-base mud containing 28 ppb Wyoming bentonite. Poly(lignin-g-(1-amidoethylene)) is formed along with poly(1-amidoethylene) in a graft copolymerization reaction of 2-propenamide on Kraft pine lignin contained in 1, 4-dioxacyclohexane. Formation of graft copolymer was proved by attachment of a derivitized, 1-amidoethylene sidechain to lignin and demonstration by U.V. spectroscopy that sidechain and backbone migrate together in a size exclusion column.

The dried, two-part reaction product is treated with aqueous base to form anionic polymers which produce the changes in mud rheology noted above. Both components of the reaction product are active in controlling mud properties.
Foaming of Anhydrous Methanol for Well Stimulation
Authors: Crema S. C. , Alm R. R.
Published: December 2007

Use of foamed anhydrous methanol for stimulation of formations sensitive to water damage is a tested technology whose wider application is limited by the relatively high cost of the additive systems needed to obtain foams of a satisfactory quality and half-life.

The additive cost has now been sharply reduced by the introduction of new foaming systems which comprise a mixture of fluorosurfactant and a foam extender. While the foam extenders by themselves do not produce stable foams in anhydrous methanol, they dramatically decrease the amount of fluorosurfactant needed to produce satisfactory anhydrous methanol foams. Several compounds have been found to perform well when used in conjunction with fluorosurfactants. Of these, nonionic surfactants based on oxyalkylated fatty alcohols and amines or polyethers containing ethylene and propylene oxide units seem to be the most efficient foam extenders. The amount of fluorosurfactant needed to obtain satisfactory anhydrous methanol foams can be decreased by as much as two-thirds when 2% of these materials are added to the methanol solution. These results give a 50 to 60% decrease in the cost of the additive package without any decrease in the foam quality and half-life.
Effect of Various Alkaline Chemicals on Phase Behavior of Surfactant/Brine/Oil Mixtures
Authors: Martin F. D. , Oxley J. C.
Published: December 2007

Recovery of crude oils which are low in naturally occurring organic acids may be enhanced by supplementing an alkaline flood with surfactant. Much of the work concerning surfactant addition to alkaline slugs reported to date has been directed toward crude oils with sufficient organic acids to produce natural surfactants. The present work considers the addition of surfactants to midcontinent-type crude oils that alone do not produce low interfacial tensions against high pH aqueous phases. This paper presents the effects of various alkaline agents on the phase behavior of brine, oil and petroleum sulfonate mixtures. Specifically, we have investigated the effect of alkaline chemicals (sodium carbonate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, and sodium silicate) on the optimal salinity of a synthetic petroleum sulfonate system.

In the first phase of the work, a normal alkane with an oil molar volume approximating that of a "J" Sand crude oil was used. Tests were performed with a simulated fresh injection water at a reservoir temperature of 160°F. This portion of the work defined the effect of the alkali and alkali counterion on phase behavior. While the presence of alkaline chemicals lowered optimal salinity, the effect was ascribed to their role as salts rather than their role in pH adjustment. Phase behavior of the system studied was sensitive to the type of alkaline cation added: potassium had a greater effect than sodium, and ammonium had the least effect. However, phase behavior appeared to be insensitive to the alkaline anion.

The second phase of the work utilized various volumes of "J" Sand crude oil with formulations of the petroleum sulfonate and alkaline solutions. Since this type of crude oil does not contain large amounts of organic acids, the alkaline/surfactant systems were not very sensitive to crude oil volumes.
The Effects of Chemical Degradation on Polymer Flooding
Authors: Clifford P. J. , Sorbie K. S.
Published: December 2007

Polymers are known to degrade chemically under reservoir conditions. In this paper we simulate the effect of chemical degradation on polymer flooding, using a modified chemical flooding code. We particularly investigate layered reservoirs, in which vertical crossflow is shown to be the leading oil recovery mechanism. The calculated effects of degradation are explained in terms of the effects of polymer on fluid flow patterns. Results are presented for different polymer and reservoir types, and the effect of non-uniform reservoir temperature on degradation rates is also studied. It is shown that there are a number of types of polymer flood in which the effects of chemical degradation are less severe than might initially be expected.
Characterization of Tracer Retention Processes and Their Effect on Tracer Transport in Fractured Geothermal Reservoirs
Authors: Walkup G. W. , Horne R. N.
Published: December 2007

Retention processes such as adsorption and diffusion into an immobile region can effect tracer movement through a fractured reservoir. In this study, retention processes have been characterized in experimental work and by the development of a two-dimensional mathematical model. A method to directly determine some important reservoir parameters, such as the fracture aperture, from the analysis of tracer tests has been developed and applied to field data.
Cal Canal Field, California: Case History of a Tight and Abnormally Pressured Gas Condensate Reservoir
Authors: Engineer R.
Published: December 2007

The Cal Canal Field, situated in the San Joaquin Valley near Bakersfield, California, produces, a rich (280 bbl/MMSCF) gas condensate from an average depth of 11,500 feet. The upper Miocene Stevens Sand, the producing formation in the field, is a very tight, abnormally pressured gas condensate reservoir. The average reservoir parameters are 12 percent porosity, .01 to .1 md permeability and a connate water saturation of 59%. The dew point pressure of 5835 psi is 1508 psi below the initial reservoir pressure. The material balance method, corrected for abnormal pressure, indicates an original wet gas-in-place of 103.3 BSCF. Production performance history suggests that the ultimate recovery from the field will be approximately ±10% of the original wet GIP. Such a poor recovery could be attributed to retrograde fallout and increasin; water saturation in the vicinity of the wellbores.

This paper presents an analysis of the reservoir characteristics and a review of its performance to date. The purpose of the study was to investigate the feasibility of improving hydrocarbon recovery from the field.
An Evaluation of the Prudhoe Bay Gravity Drainage Mechanism by Complementary Techniques
Authors: Haldorsen H. H. , Rego C. A. , Chang D. M. , Mayson H. J. , Creveling D. M.
Published: December 2007

The gravity drainage mechanism in the Prudhoe Bay Field has been evaluated by means of repeat Compensated Neutron Log (CNL) data, centrifugal gas/oil displacements in small preserved cores, and by an analytical stochastic approach.

From the repeat CNL data, in-situ displacement efficiencies as observed above the advancing gas-oil contact in 50 gravity drainage wells have been estimated. A Monte Carlo-type error analysis is presented to give the range of uncertainty associated with the results.

Gas/oil centrifuge displacements in small preserved cores were performed in order to validate the CNL results, and to investigate the time dependency of recovery in gassed out zones which is otherwise beyond CNL resolution. Conventional scaling theory was subsequently used to find homologous times for the reservoir and laboratory models, thus making comparisons (between CNL and centrifuge data) possible. In addition, relative permeability to oil (to be used in the analytical study) was computed from the centrifuge data.

Finally, an approximate analytical description of the gravity drainage process was formulated and a Monte Carlo analysis performed to cover the wide range of values the input parameters in the equations may take on. This analysis yields a statistical distribution in displacement efficiencies at each point in time. The "average" behavior may be compared to the CNL and centrifuge data.

The results demonstrate that the gravity drainage mechanism in Prudhoe Bay is very time-effective and yields high quantifiable displacement efficiencies. The consistency obtained among the various evaluation techniques gives confidence in the results.
Development of the Khuff Gas Reservoir, Bahrain Field
Authors: Janahi I. A. , Dakessian B. A.
Published: December 2007

The Khuff gas reservoir in Bahrain was discovered in 1948 when a shallow crestal Well No.52 was deepened to a depth of 10,078'. The reservoir was not developed until late 60's when the country planned to embark on an industrialization. scheme that would rely on Khuff gas as the main source of energy. Two commercial development Wells 254 and 255, were drilled in 1969 to meet the demand for a newly constructed alumimum smelter. Nine more wells were drilled during the 70's as the relatively lean Khuff gas replaced the richer Arab Zone gas for injection and artificial lift in the oil field, for municipal power generation and for use as feed stock and fuel in the local refinery. With the continued industrial expansion in Bahrain the need for Khuff gas was greatly increased and as a result a 10-well development drilling program was undertaken in 1982.

Khuff gas consumption has increased 50 MMSCFD in 1969 to around 400 MMSCFD in 1984 at an annual growth rate of 15%. Excessive growth will not only create the need for huge investments but will also rapidly deplete this vital resource. Future demand should be forecasted and controlled at this early stage of depletion to properly manage the reserovoir and, if necessary, to seek an alternative source of supply.

The objective of this paper is to outline a development/production strategy for the Khuff Reservoir based on deliverabilities and estimated reserves.
Oil Pollution Control Equipment and Facilities
Authors: Scott G. A.
Published: December 2007

Development of a pollution response capability to match offshore exploration and development often goes unnoticed until a major incident occurs. At that time one hopes that like the fire extinguisher on the wall it may be unnoticed but it is available when needed. During the 1980 Hasbah spill Aramco found that the in-house spill response capability had not kept pace with offshore development. There were more than 300 offshore production wells and five production platforms each of which had a potential for large scale oil releases. The spill response effort had been focused on terminal operations and needed upgrading to meet the needs of offshore development. Therefore a major study was initiated to determine overall spill response needs for the entire offshore activity.

In order to focus the study on exploration and production needs the study team was given the following criteria to follow in developing the response needs:

To accurately evaluate Aramco's current offshore spill response capabilities. Develop containment and recovery systems and also dispersant application systems capable of dealing with a spill of up to 70,000 barrels in the Gulf under favorable conditions. To recommend an organization with trained manpower to effectively handle in-house offshore spills. To provide an estimate of the costs involved in purchasing the recommended equipment.
Rock Bits Equipped With Extended Nozzles Lower Drilling Cost in the Middle East Region
Authors: Selby B. A. , Sauvageot W. A.
Published: December 2007

An analysis of three-cone rock bit runs using extended jet nozzles (EN) in the Middle East Region is presented.

These runs were made from 1982 to 1984 in several Middle East countries. They represent wells drilled onshore and offshore, vertical and deviated, using oil and water based mud systems.

The improvements in performance gained by enhanced hole cleaning with extended nozzles are well documented.

This feature has been widely used in the South East Asia – Far East region and in certain areas of the continental U.S.A. and Alaska since the mid – 1970's.

The result of the EN runs in the Middle East correlate well with results in the proven areas elsewhere in the world. Penetration rate increases over regular jet bits of 7-80% have been recorded.

The high daily rig costs characteristic of Mideast drilling operations make it fairly easy to show a cost per foot decrease with only slight increases in performance.

The increased bit cost due to the EN feature is found to be virtually negligible.
Dynamic Measurement of Drilling Fluid Rheology at Elevated Temperature and Pressure
Authors: Moussa M. M. , Al-Marhoun M. A.
Published: December 2007

Due to instability and degradation of the conventional drilling fluids specially under high shear rate, elevated temperatures and chemically complex environments of deep and geothermal wells, it is essential to modify and develop stable batches of clay suspensions that can perform adequately under these conditions. To obtain batches, a reliable set-up should be designed and constructed to examine and measure all the properties that may possibly change under the prevailing conditions. A scaled dynamic flow loop is designed and built in the Department of Petroleum Engineering at the University of Petroleum & Minerals, Dhahran.

This set-up can simulate efficiently the bottomhole condition e.g. high temperature up to 450°F, high shear rate up to 50,000 sec−1. The system pressure is maintained above the saturation pressure of water at the test temperature. Dynamic filteration rate and the corrosion rate is monitored instantaneously at wide range of bottomhole conditions. The flow parameters N&K,τ, γ etc., are obtained by measuring AP across the 3-tube viscometer using the DP 15-150 pressure differential transducers. The ambient properties are measured by Baroid multi-speed viscometer and compared with data obtained from the loop.

Two batches composed of sepiolite and polymer were tested. Effective viscosity is increased significantly at high temperature for the first and second batches. The consistency and thermal stability of these fluids may be attributed to the transfer of sepiolite to smectite at high temperature and high shear.
Deliverability Projection Model for Overpressured Gas-Condensate Reservoirs
Authors: Aziz R. M.
Published: December 2007

During the depletion history of an abnormally pressured reservoir, pressure is initially maintained by a decrease in the pore volume. The P/Z vs cumulative gas produced graph in such reservoirs shows two distinct slopes and the initial gas in place can be estimated by extrapolation of P/Z straight line after the reservoir gradient has been reduced to normal. This decrease in pore volume also results in a reduction in the effective permeability of the rock thus affecting the formation in-flow performance.

In the gas-condensate reservoirs, hydrocarbon liquids drop out of the gas phase below the dewpoint pressures increasing the total liquids saturation. An increase in the liquid saturation decreases the relative permeability to gas.

The paper develops a high pressure gas-condensate reservoir deliverability calculation incorporating the effect of gas permeability reduction due to a decrease in pore volume and increase in oil saturation.
The Formation of Salt Balls in a Deep Exploratory Well
Authors: Samhouri F. A. , Al-Chalabi A.
Published: December 2007

A high pressure salt water influx was encountered while drilling a Deep Exploration well at 20,363 ft. Attempts were carried out to control this influx but the well killed itself. The fishing operations revealed the drill pipe to be plugged with salt balls. The paper describes and analyses the phenomenon that resulted in the formation of the salt balls which subsequently plugged the drill pipe and led to the killing of the well.
A Compositional Simulator for Performing Large Field Studies in a Vector Computing Environment
Authors: Harper J. L. , Heinemann R. F. , Ray M. B. , Stephenson P. E.
Published: December 2007

This paper describes COSMOS, a new equation-of-state, compositional simulator. COSMOS is designed for full-field studies of hydrocarbon gas and carbon dioxide injection for miscible flooding, gas condensate reservoirs and volatile oil reservoirs. The numerical procedures in this simulator are based on Newton's method and couple together the phase equilibrium constraints and species continuity equations. The transport flux terms in the flow equations may depend on pressure alone, or may be treated as implicit functions of both pressure and saturation. With this latter option, COSMOS contains the coupling terms which give fully-implicit, black-oil simulators their stability. The well management package is flexible and provides for platform and field limits as well as individual well controls. The coupling of the well flow equations with the continuity equations parallels the implicit treatment of the transport terms. This implicit option also affects our linear algebra routines which are capable of solving matrices with one or three unknowns per grid block.

COSMOS was constructed as an efficient vector code which can be easily modified as simulation needs or capabilities arise. Structured design methodologies were employed to achieve as high a degree of modularity as is consistent with extensive vectorization. COSMOS contains a resource manager to efficiently run large and small problems within a limited central memory. Additional resource management software determines a critical path to optimally schedule computations and data traffic. We have also developed a flexible, hierarchical data base package for the storage and retrieval of data which provides printing and restarting capabilities. Although the COSMOS code and these software packages were targeted for the CRAY-1, the simulator is designed to run on other machines with a minimal number of changes.
Reservoir Management of the Yibal Field in North Oman: A Simulation Approach
Authors: Blaskovich F. T. , Thurber S. S. , Echols D. P. , Al-Hinai K. B. M.
Published: December 2007

This paper describes the techniques used and results derived during a reservoir simulation study of the Shuaiba Reservoir in the Yibal Field in North Oman. This was the final portion of a comprehensive study of the Shuaiba Reservoir that was begun in 1981. An extensive geological, petrophysical and reservoir engineering analysis was performed and described in a previous paper1. Reservoir simulation studies were then conducted to understand past performance and to determine the best operating plan for the future.

The reservoir simulation was conducted in three phases. In the first phase, a full field coarse grid model was used to determine the predominant drive mechanism and direction of fluid movement in the reservoir. Based on the results, very detailed single well (mini-sector) studies were performed to investigate fault plane water movement in the highly faulted crestal portions of the field. Finally, sector models were used to study areal and vertical sweep efficiencies and to determine an operating strategy that would maximize oil productivity and recovery in the future. The results of this work defined a coherent development plan for the major oil producing regions of the reservoir that was then extrapolated to the entire field.
Interference Testing: A New Analysis Approach
Authors: Al-Marhoun M. A.
Published: December 2007

A new mathematical and graphical approach to analyze the interference tests is presented. This is based on a mathematical manipulation of the line source solution to the diffusivity equation. This approach yields the exact exponential integral function solution in a straight line form if pressure versus the inverse of time is plotted on a specially devised exponential integral graph paper. Obtaining a straight line on such a graph paper makes the analysis of inter ference tests very simple.
EPT Applications in the Middle East
Authors: Chardac J. L. M.
Published: December 2007

The Electromagnetic Propagation Tool was originally intended to be run only in fresh-water environment. However, in Middle East its range of applications have been expanded as much as possible. It has been used as a formation-water salinity estimator on one test well. Another unusual application is oil-base mud logging, which is becoming more and more frequent. A field example is presented.
Daily Monitoring and Control of Well Performance: A Novel Approach Applied in the Upper Zakum Field
Authors: Al-Tamimi Y. K.
Published: December 2007

This paper presents a review of the unique field monitoring & control system already installed on the Upper Zakum field, offshore Abu-Dhabi in the United Arab Emirates. This system may be considered as a pioneer project of its kind in the Middle Eastern Oil Industry.

The size and scope of this project is given in the proceeding general description of the field and its development philosophy. Followed by description of the Telesystem and its use as a hierarchical distributed control and data acquisition system.

The paper is then concluded with an appraisal of the system by highlighting its merits and demands.
Artificial Lift by Hydraulic Turbine Driven Downhole Pumps
Authors: Riddet David A.
Published: December 2007

The Introduction of Hydraulic Turbine Driven Downhole Pumps for artificial lift applications has overcome many of the problems associated with other forms of artificial lift. This paper will describe the downhole pump itself and will also describe its application in source water wells and oil wells.
State-of-the-Art of Water Coning Modelling and Operation
Authors: Alikhan Abbas A. , Ali S. M. Farouq
Published: December 2007

Water-coning is often a serious operational problem in oil formations with underlying water. In the Middle East, some of the largest oil reservoirs have water-coning problems. The operation of a field under water-coning can employ a number of strategies, ranging from production limitation to production at maximum rate, possibly with interval control. This paper reviews the state-of-the-art of water-coning from the point of view of field operation, experimental modelling and numerical simulation. Selected field examples are cited.

It is shown that water-coning control measures are of limited efficacy at best, under practical conditions. Other techniques, such as barriers, are of academic interest only. Production at very high rates – with concomitant high water production rates – can be problematic in the Middle East reservoirs, with very highly saline connate water.

Simulation of water-coning and/or gas coning is possible on a single well basis. However, it is still not practical to simulate water-coning on a fieldwide basis. The numerical difficulties involved and some of the solutions proposed are discussed.

Experimental modelling of water-coning has been fairly successful, again on a single well basis. Occasionally, numerical simulation has provided useful backup to physical modelling. Types of experimental models used are reviewed.

On the whole, the paper provides a useful view of all aspects of water-coning, and should be of value to large segment of petroleum engineers and researchers.
Temperature Distribution Around Water Injectors: Effects on Injection Performance
Authors: Platenkamp R. J.
Published: December 2007

When cold water is injected into a reservoir at initial temperature conditions, the sands around the water injector into which injection occurs will be cooled down to virtually the temperature of the injected water. The resulting temperature distribution can be described by simple expressions even in the case of a multi-layered reservoir. The presence of such a cold water bank has a strong bearing on injection performance. In order to arrive at a correct interpretation of pressure fall-off surveys conducted in water injectors it is essential to take the temperature distribution into account. Some field examples will be discussed.
Impact of Investment Criteria, and Reservoir Characteristics, Taxes, Royalty, and Price on Optimal Field Development Plans
Authors: Dougherty E. L. , Lombardino E. , Hutchison P.
Published: December 2007

A system which combines a gas reservoir simulation model with optimal development and production scheduling models has been used succssfully for some time to develop long range plans for an oil and gas/NGL producing complex. The system determines how to integrate gas production from more than 40 reservoirs over a 25-year horizon to maximize net present value (NPV) while meeting sales requirements.

The timing of drilling wells and installing compressors, as well as the number of each such facility, is affected by economic factors (taxes, royalty, price of products, cost of development and production), reservoir characteristics (permeability of producing layers, heterogeneity, conductivity of induced fractures, gas composition, gas in place) and investment criteria. The criterion determining investments to add to the development schedule is PWPI; the incremental PWPI of each facility added to the optimal schedule must exceed a cutoff value of PWPI. The sensitivity of the optimal development schedule and desired depletion rate to various parameter changes are presented for (a) a single reservoir with an unlimited market, (b) a single reservoir with a limited market, and (3) two reservoirs with a shared market.

For (a) the results reveal considerable variation in the sensitivity to the parameters considered. For (b) the results illustrate the danger of oversaturating investment in a producing reservoir. For (c) the findings show that in some instances the complex interactions between economic and reservoir parameters and market specifications give rise to an optimal strategy which does not agree with intuitive expectations; sometimes, using negative cutoff values of PWPI results in larger values of PWPI.
Government Regulatory Practices in Transition
Authors: Kutchins G. L.
Published: December 2007

The exploration for new energy and the resultant economics of new finds is in transition, especially as it applies to exploration on government lands where there are constantly new regulations for most exploration development and production activities. Politics, not science, is the main force behind the transition and change. Surface land "experts", called "range specialists", rather than sub-surface experts regulate most exploration and development activity.

When the three E's -- Energy, Economics, and Exploration -- are in transition, as they are today, it is all the more important that we in the business of exploring for and developing more economical energy practice the three C's -- Communication, Cooperation, and Coordination -- with the people who regulate our industry.
Drilling, Production, Deregulation, and Pricing in the Wellhead Natural Gas Market Under the Natural Gas Policy Act
Authors: O'Neill R. P.
Published: December 2007

Since 1978 the natural gas market has changed radically in response to NGPA pricing policies, changes in world oil prices, and changes in energy markers. These changes have affected new drilling as much as any other part of the industry. In 1981 drilling activity reached all-time highs. This paper examines the course of natural gas drilling since the NGPA, examines the effects of post-NGPA drilling on production, and provides estimates of the quantities of gas deregulated.
Comparison of Methods for Determining Fair Market Values
Authors: Gustavson J. B.
Published: December 2007

When an operator seeks financing of a venture, he generally provides information relating to his oil and gas reserves, as well as to his company's financial status. It is often left up to a bank, to a new venture partner or to a potential buyer to form his own opinion about the actual value of the reserves and the operator's ability to recover these. This paper will show how to bridge the gap between a conventional reserve estimate and the Fair Market Value of a property.

The paper first discusses the necessary reserve report as well as the often overlooked review of the operator's capabilities. The paper then discusses four different methods of determining the Fair Market Value of a property, and specifically point out sensitivities of the various assumptions used in the valuation methods. These appraisal methods include the following: Value per BOE. Gross recoverable barrels in the ground of both oil and oil-equivalent gas are determined through conventional reserve estimating. The barrels in the ground are multiplied by a dollar amount which reflects the risk and time period required to recover the oil (usually $7.00 per barrel). Non-producing reserves and proven, undeveloped reserves can be further discounted.Risked Present Worth. Present worth is first determined by an escalated future cash flow discounted back to present worth. Sources of risk include any lack of history of the producing formation, the operator's inexperience, and the time span over which the reserves will have to be recovered. A percentage in the 30 to 75% range is applied to the present worth of the property to account for these various risk factors.Three-year Cumulative Cash. The Fair Market Value can be determined by establishing a time criteria for payback of the acquisition price. The net cash flow is summed up from the present to the end of the selected time period (usually two-and-a-half to four years).Present Worth at 25%. A desired internal rate of return is targeted. The future net cash flow is discounted by this amount to establish a Fair Market Value. This method can also be adjusted to consider risk.

Cases are used to illustrate where the various methods are applicable and generally agree, as well as cases where pitfalls exist.
Guidelines for Proper Application of Four Commonly Used Investment Criteria
Authors: Dougherty E. L.
Published: December 2007

Two aspects of the most favored investment criterion; discounted-cash-flow rate of return (DCFROR), continue to confound evaluation engineers. These are how to interpret the value obtained, and what to do when dual values arise. Using continuous discounting formulas, it is demonstrated mathematically that when a single value is obtained, DCFROR is the rate of return realized on the unamortized investment.

Three alternative investment criteria used to cover the breach caused by the occurence of dual values of DCFROR are a modified DCFROR, growth rate of return (GROR) and ratio of net present value to present worth of invesment (PWPI). It is shown that the modified procedure for computing DCFROR must be applied to all projects to obtain a consistent measure of investment performance; because a standard modification cannot be defined far all projects, modified DCFROR is unsatisfactory as an economic evaluation yardstick. PWPI always provides desired consistency. GROR, which is analytically related to PWPI, provides a consistent measure if the same year is used to compute the future value for all projects. As is demonstrated, with these latter two criteria care must be exercised to specify the investment properly.

Rapid increases in oil and gas prices, followed by similar runups in costs, followed in turn by a price decrease, have caused analysts to more commonly escalate prices and costs in evaluations. These escalated numbers may then; (1) be used directly, or (2) be deflated and the resulting values used, to calculate economic yardsticks. In the second case depreciation deductions are also deflated. The rates of return obtained via these two procedures differ by the inflation rate, but, if followed properly, both procedures yield the same value of PWPI.
An Improved Computation Procedure for Risk Analysis Problems With Unusual Probability Functions
Authors: Startzman R. A. , Wattenbarger R. A.
Published: December 2007

A computational method called Latin Hypercube Sampling (LHS) has been developed. LHS is superior to Monte Carlo simulation for risk analysis problems which involve discrete probability distributions containing events having very small probabilities but drastically large effects on the final solution.

The LHS method is applied with evenly spaced probability intervals for a random variable. Each interval is then sampled without replacement, thus avoiding clustering of values.

Monte Carlo simulation has the disadvantage that random samples may become clustered in an apparent biased fashion until a large number have been selected. LHS, in effect, forces samples to correspond more closely to a given probability distribution earlier in the selection process. Examples are shown comparing the number of computations with Monte Carlo simulation, which has a very slow convergence in the example cases, to a relatively accurate and rapid computation by the LHS method.

We were able to show that the LHS method can be used to advantage in problems having smooth probability functions as well as abnormal probability functions.
Reservoir Economic Optimization
Authors: Nystad A. N.
Published: December 2007

This paper outlines a reservoir-economic approach and quantifies the microeconomic adjustment of the exploitation of different types of petroleum reservoirs by means of a numerical optimization model.

The numerical reservoir-economic optimization will be presented here. In this model the microeconomic adjustment is viewed in relation to reservoir engineering. The model optimizes the exploitation of an oil or gas reservoir in terms of: 1) Total depletion rate (production capacity, including the aspects of Maximum Efficient Rate) and, 2) Geographical distribution of total production capacity (well density, number of platforms, etc).

The model can be adjusted (calibrated) to the reservoir simulations of a specific oil or gas reservoir. The generation of production profiles is based on a limited number of reservoir simulations. This information is used to generate a fine network of production profiles in the reservoir module. The income side is coupled with a reservoir cost module and the optimal solution is sought in the net present value surface. The model is used for further economic analysis in different economic, financial and taxation modules.

It may serve to improve the general understanding of the effects of reservoir economics on the engineering decision-making process, and as such is a tool for communication between economists and reservoir engineers.
Relative Economics of Domestic Oil and Gas Exploration and Development, 1978 to 1983
Authors: Glanville T. S.
Published: December 2007

This paper analyzes the relative economics of domestic oil and gas exploration and development for the period 1978–1983 by constructing annual ratios of oil and gas prices to their finding cost. This analysis is done in the context of the economic theory of depletable natural resources and the causal factors that determine the domestic net prices and finding cost for oil and gas. The paper concludes that industry economics improved in 1983 from the peak levels of industry activity in 1981 and 1982 due to oil price stabilization, a fall in Windfall Profits Tax (WPT) liability and operating costs, increases in gas prices, and a large drop in finding cost.