bluuebunny/crossref_metadata_2025_split huggingface dataset:
Treatments To Improve the Performance of Injection, Disposal and Water Supply Wells
Authors: Moore J.M. , Rollins J.T. 
Published: December 2007

Introduction
Service wells are necessary to the efficient recovery of petroleum. If costs are unnecessarily high due to wasted horsepower expended in operating these service wells, the net income from the lease is reduced. For maximum profits, service wells should be maintained at peak operating efficiency, the same as production wells. Many conditions can prevent service wells from Operating at peak efficiency. Evaluation of bottom-hole samples and surface conditions facilitate problem analysis and selection of remedial measures. Acidizing, fracturing, formation clean-up and similar techniques are designed to obtain and preserve maximum permeability in the critical area around the wellbore.

Classification
Service wells may be classified as:water injection wells,gas injection wells,brine disposal wells, andwater supply wells.
Problem identification and elimination can be greatly facilitated by an accurate analysis of well conditions and a subsequent recommendation for proper corrective treatments. Such treatments fall into three categories:initial treatments to permit new wells to operate at maximum capacity,preventive treatments to avoid difficulties inherent in a specific formation or area, andworkover treatments to restore maximum operating efficiency to formations which have been damaged.
l plugging of formation flow channels by various materials is the usual cause of inefficient operations. Such plugging may be due to one or more of the following:Mineral deposits ("gyp")Corrosion products (iron oxide, sulfide)Silicate particles (silt, clay and fine sand)Petroleum residuals (paraffin, asphalt, tar)Organic deposits (bacterial, algeal)
Mobility Weighting in Numerical Reservoir Simulation
Authors: Potempa T. 
Published: December 2007

Abstract
The sensitivity of a numerical steamflooding model toward mobility weighting and discretization procedures is examined in depth. Four numerical discretization schemes are used: a five-point finite-difference model, a nine-point method similar to that proposed by Yanosik and McCracken, a seven-point scheme, and a method related to the finite-element method. Three mobility-weighting schemes are studied, including the upstream mobility-weighting approach often used in simulation today. The results of this investigation demonstrate that both accurate numerical procedures and the correct mobility weighting are needed to produce realistic simulations in an example problem. In particular, the standard upstream mobility-weighting approach is shown to produce unrealistic simulations regardless of the discretization scheme used.
Pilot Propane Project Completed in West Texas Reef
Authors: Sturdivant W.C. 
Published: December 2007

Abstract
Injection of a 14,000-bbl "slug" of propane into a reef reservoir in an advanced stage of gas injection operations has resulted in miscible displacement of 100,000 bbl of stock-tank oil. Premature breakthrough of gas injected behind the slug is attributed to dilution of the propane slug, to unfavorable permeability distribution and to an insufficient amount of propane.

Introduction
The Millican field pilot propane project was intended to evaluate the applicability of the propane slug method to the Millican field (Fig. 1). A slug of 14,000 bbl of propane-butane mixture was injected in a single well followed by injected gas, and behavior of offset wells observed for two years.
Recognized hazards were the high gas saturation due to the past history of gas injection and the non-uniformity of reef rock. Also, economic considerations limited the amount of propane which could be injected in a possible field-wide application. Favorable factors were a light oil containing a high proportion of intermediate hydrocarbons (see Table 1), gas injection facilities already in operation and a supply Of propane from a nearby gasoline plant.
Despite the recognized hazards, project economics were considered favorable, since costs were low and any reduction in gas-oil ratio brought about by propane injection would be immediately reflected in increased oil production.

History of Millican Field
The Millican field, located in Coke County, Tex., produces from a Strawn reef limestone at 6,000 ft. Originally, the field had two small gas caps, and periodic material balance calculations indicate a closed reservoir. The oil was saturated at the original pressure of 2,540 psig at - 3,720 ft with 1,300 cu ft of gas per barrel and had a formation volume factor of 1.65.
From core analyses, average porosity of the productive section of the reef is estimated at 6.6 per cent, connate water saturation at 20 per cent, and average permeability, 10 md. The field is completely unitized and produced gas has been returned since early in the history of the field.
New Technique Provides Open-Hole Production Test of Wildcat Formations
Authors: Malone B.C. , Stokey Ernest W. 
Published: December 2007

Introduction
It is becoming increasingly difficult to find proved oil reserves within the boundaries of the United States. In general, companies must drill much deeper in their search for oil.
The depth of present-day wildcat wells and the complex completion procedures used on such wells have brought about a large increase in the cost to put oil back in the tank battery. This skyrocketing of costs has stimulated a constant search for new or improved methods in every phase of drilling for oil.
A new testing technique which has helped to a great extent the struggle to cut the cost of finding oil reserves provides conclusive evaluation of questionable wildcat formations without the expense of running casing.
The technique and tools used were made available to the petroleum industry in the latter part of 1956. To date, conclusive information has been obtained on more than 200 wildcat formations located in Arizona, Utah, New Mexico, Colorado, Wyoming, Kansas, Oklahoma, Illinois, the Texas Panhandle, North Central Texas, the Permian Basin of West Texas, and Southwest Texas.
Successful open-hole production tests have been performed in porous lime, consolidated lime, fractured lime, vugular lime, conglomerate, consolidated sand, coarse sand, shaly sand and red shale.

Need of Supplement For Conventional Testing
The conventional drill-stem test is the most widely used method to obtain information for the evaluation of the potential production of a formation. When pressures and fluid are obtained in sufficient amounts, the drill-stem test gives exact and conclusive in formation on formation potential. However, quite often a drill-stem test is either void or obtains very little yield of fluid or pressure. This would lead to the normal conclusion of poor production potential.
When electric logs indicate possible fluid and a void drill-stem test results, it is possible that the formation has been blocked or plugged by the drilling mud. This blocking action can be of varying degrees. A partial block may occur to give only a slight show of formation pressures and fluid and, thus, indicate poor potential. Therefore, when test results are poor but logs give indication of production, the test is inconclusive. It then becomes necessary or desirable to more thoroughly test the zone, or zones. In order to obtain more conclusive in formation under such conditions, an acid treatment may be required to break down the suspected mud block. When the mud block has extended well into a permeable zone, a substantial treatment is often necessary. Very high pressures normally occur while breaking through these blocked permeable zones.
Casing Temperature Studies in Steam Injection Wells
Authors: Leutwyler Kurt 
Published: December 2007

Abstract
The key to realistic casing stress analysis in thermal recovery installations is accurate knowledge of the temperatures involved. Much information leading to prediction of heat losses from tubing string to wellbore has been published. This same information permits calculation of casing temperature under certain conditions. This paper reviews the basis for most of the published work, the line sources solution to the diffusivity equation and examines some of its application criteria in the light of unsteady-state conditions. An alternate finite differences method is presented for correlation, and experimental data pertaining to the heat transfer mechanism in the annulus is reported. In the light of the information presented in the paper, it appears that the assumption of a line source for the tubing-wellbore system is valid even for reasonably short periods of heat flow, such as "steam soak" operations. The empirically modified equation presented earlier matches computer derived results of the finite differences approach for periods as short as 50 hours. Previously predicted casing temperatures and the associated stress levels are thus verified based on these correlative computations and the reported experimental information. Fall-out from the computer output resulting in some studies of the influence of insulating cement properties on casing temperature, and experimentally studied effects of nitrogen placed in the annulus at various pressures, are described.
Introduction
Generally speaking, predictions of average casing temperatures have been based on an idealized model involving a centralized tubing string at uniform constant temperature radiating energy towards the casing under steady-state conditions. Heat is transferred away from the casing to the formation by unsteady-state conduction across thermal barriers consisting of cement and the mud sheath., Heat balances written on the casing permit prediction of instantaneous casing temperatures. During early periods of injection, casing temperature varies appreciably as a function of time; however, for long injection times this variation decays as heat flow from the wellbore to the formation stabilizes, and it becomes virtually negligible as conditions surrounding the wellbore become quasi-steady-state (Fig. 1). Carslaw and Jaeger describe a solution to the diffusivity equation for a line source (Fig. 2). A constant supply of heat is introduced into the medium from the line placed into the origin of the x-y coordinate system and parallel to the z-axis. Heat spreads outward in the infinite cylindrical solid and the temperature increase on a line going through point (x, y) parallel to the z-axis at a distance r can be predicted by:
.....(1)
JPT
P. 1157ˆ
Development of a New Aluminum/Polymer Gel System for Permeability Adjustment
Authors: Dovan H. T. , Hutchins R. D. 
Published: December 2007

Summary
A new method for gelling Polyacrylamide with aluminum has been developed to reduce the effect of reservoir heterogeneity, resulting in improved waterflood efficiency and higher oil recovery. The method uses a soluble aluminum compound in a high-pH, nonreactive form that is mixed directly with the polymer at optimum concentrations. Polymer gelling occurs in the reservoir when reactive aluminum is generated by consumption of hydroxyl ions. Variations in gel strength and gel time are obtained by adjusting polymer and aluminate concentrations in the slug to the desired levels. This process has several advantages over the current aluminum citrate technology as well as the chromium redox bulk gel system. Although the process works best in freshwater systems, it can be modified to accommodate waters with higher brine content. Laboratory development of the process and a successful profile modification field trial are described.
Evaluation of an Analytic Technique for Estimating Swept Volume from Thermal Pressure Falloff Tests in Heterogeneous Systems
Authors: Fassihi Mohammad Reza 
Published: December 2007

Summary
Several simulated pressure falloff tests were analyzed to see whether the swept volume estimated by an analytic technique agrees with the swept volume simulated with both a steamflood model and an in-situ combustion model. Several parameters, such as wellbore gridblock size, nonuniform permeability, layering, flowing noncondensable gas, and oil vaporization, were studied. The analyses of these runs also led to the evaluation of other parameters, such as permeability-thickness, kh, in the swept zone. For steamfloods, the analytically estimated swept volume in relatively homogeneous models is in agreement with the simulated swept volume. The calculated kh reflects the effective gas permeability-thickness at the average gas saturation behind the steam front. The presence of gas-saturated oil or flowing noncondensable gas ahead of the steam front causes a long transition between the end of the infinite-acting period and the start of pseudo steady state. For very heterogeneous reservoirs, there was a long transition period that masked the pseudosteady-state data.
For in-situ combustion, the onset of the pseudosteady-state period depends largely on gas mobility at the front. For high gas mobility, the analytically calculated swept volume was found to be highly overestimated. However, it approached the simulated swept volume as gas mobility decreased.
Transient Interfacial Tension Behavior of Crude-Oil/Caustic Interfaces
Authors: Sharma M. M. , Jang L. K. , Yen T. F. 
Published: December 2007

Summary
A systematic study is conducted to describe the transient interfacial tension (IFT) behavior of crude-oil/caustic interfaces. The variation in this behavior with variation in the composition of the aqueous phase and other parameters is the focus of this study. It is found that at low pH values, the experimentally observed behavior is similar to that reported earlier. At high pH values, however, a maximum in IFT is observed, followed by a minimum at a late time. Sodium chloride is shown to have no significant effect on the shape of the transient IFT curve, but the absolute values of IFT are at lower NaCl concentrations. Divalent ions dramatically increase the IFT.
A chemical model that takes into account the kinetics and the detailed chemistry of the process is used to explain the observed phenomena. The phenomenological surface phase approach is used to model the interface. The resultant set of ordinary differential equations is linearized by making certain justifiable, simplifying assumptions. The analytical solution to the set of equations yields the variation of the various concentrations with time. The IFT is then related to the interfacial concentration of the surface-active species, As− by the Gibbs equation. The variation in the transient IFT behavior on changing the kinetic constants, phase volumes, and ionic concentrations is discussed. Finally it is shown that the extension of this model to a two-component model would successfully explain all the experimentally observed phenomena.
Effect of Oil Type on Solubilization by Amphiphiles
Authors: Bourrel M. , Verzaro F. , Chambu C. 
Published: December 2007

Summary
Systems optimized for micellar flooding are not all equivalent in terms of solubilization, interfacial tensions (IFT's), and oil recovery efficiency. The basic conditions that promote high solubilization into microemulsions, a property correlated to the values of IFT's, were established in a previous paper. Changes in oil type, for example, have to be compensated for by adjustment of the lipophile of the surfactant; however, this is not always sufficient to guarantee a high solubilization.
The purpose of this paper is to investigate the influence on solubilization of the relationship between the oil type to be solubilized and the surfactant lipophile. We found that this relationship is a determining factor for solubilization at a given temperature and salinity. For example, we observed that for the alkane series, solubilization is not affected by the alkane carbon number (ACN), provided that the compensation be achieved by adjustment of the surfactant lipophile length. For other oils or mixture of oils, like crudes, however, this is not necessarily the case; the solubilization may be found to be more or less different from that of alkanes, depending on the structure of the surfactant lipophile.
A particularly interesting case of oil mixtures is mixtures of hydrocarbons and methane (under pressure), because this gas is often dissolved in substantial amounts in live crudes. The incidence of the presence of methane is shown to be a function of the amount of gas dissolved and of the nature of the dissolving hydrocarbon. An interpretation of the results is proposed, based on the oil/lipophile, oil/oil, and lipophile/lipophile interaction energies, which are involved in Winsor's R-theory.
Analysis of the Low-Tension Pilot at Big Muddy Field, Wyoming
Authors: Ferrell H. H. , King D. W. , Sheely C. Q. 
Published: December 2007

Summary
Conoco Inc. initiated a low-tension pilot test in 1973 at the Big Muddy field east of Casper, WY. The process mobilized an oil bank ahead of the slug, reached a peak oil cut of 20 %, and recovered 36% of the residual oil saturation (ROS). Tracers were injected in the preflush and postflush to determine swept volumes and distributions of flow. Tracer responses showed that more than 95% of the flow to the center well of the five-spot came from the two northern injection wells. The overall performance of the pilot was analyzed with a numerical simulator.
As a result of the pilot and the supporting research, a nearby 90-acre [36A-ha] commercial demonstration low-tension flood was initiated in 1980 and was operated as an EOR project until July 1985, although oil production still continues.
A Demonstration of The Effect of "Dead-End" Volume On Pressure Transients in Porous Media
Authors: Fatt I. 
Published: December 2007

Abstract
Study of a model which contains "dead-end" pore volume indicates that pressure transients are influenced by the amount of dead-end pore volume and by the resistance of the flow path between the dead-end pore volume and the main flow channels. A semi-empirical method is demonstrated that makes possible measurement of the volume in the dead-end pores and the total pore volume. The difference between these two volumes is the volume of the flow channels. An indication of the flow resistance between the dead-end pore space and the main flow channels is also obtained.

Introduction
In some engineering calculations the distribution of pore volume in a petroleum reservoir need not be known. For example, a material balance calculation treats a reservoir as an oil-filled tank. In other calculations the distribution of pore volume appears implicitly through use of the porosity and the relative permeability and capillary pressure characteristics. It is the purpose of this paper to point out that under certain conditions the exact distribution of pore volume must be known in order to interpret correctly transient flow behavior.
Eqs. 1 and 2 for a one-dimensional system require that, at any point x and at any time t, the average velocity vector be in the x direction. Furthermore, at any x and t there can be only one value of P. Also, all of the fluid leaving an element dx must have been stored in that element since t=0 as a result of the compressibility of the fluid or must have come in from the adjacent downstream element. In other words, no fluid can be generated in dx. These conditions are fulfilled for a homogeneous, isotropic porous medium.
In fractured rock the over-all permeability of the system may be greater than that of the material making up the blocks. The blocks may then be sources. A vuggy limestone can be treated in a very similar manner. If there is a low permeability layer on the vug surface, the fluid in the vug may not be able to leave at a rate sufficient to make the pressure in the vug equal to that in the rock immediately around the vug. The vug then becomes a source and the system obeys Eq. 3 or Eq. 4.
Improvements in Physical-Property Models Used in Micellar/Polymer Flooding
Authors: Camifleri D. , Fil A. , Pope G. A. , Rouse B. A. , Sepehrnoori K. 
Published: December 2007

SummaryThis is one of three companion papers describing a micellar/polymer or chemical flood simulator and comparing its results to experimental data. Various physical-property models required by chemical flood simulators have been improved and others developed. The most significant development is the use of pseudophases to model phase behavior. The method allows representation of four pseudocomponents. This is made possible by assuming that alcohol is distributed among the other three pseudocomponents, thus forming three pseudophases that are assumed to be in thermodynamic equilibrium. Another improvement relates to the ion-exchange model. Cations are considered to exchange with both surfactant micelles and clays. The model assumes the exchange to be entirely a result of electrostatic association. A model for treating physical dispersion coefficients as a function of saturations has been added. The model is based on experimental evidence and is purely empirical.
Determination of Interstitial Chloride in Shales and Consolidated Rocks by a Precision Leaching Technique
Authors: Manheim F. T. , Peck E. E. , Lane C. M. 
Published: December 2007

Abstract
We have devised a technique for determining chloride in interstitial water of consolidated rocks. Samples of rocks ranging from 5 to 10 g are crushed and sieved under controlled conditions and then ground with distilled water to submicron size in a closed mechanical mill. After ultra-centrifugation, chloride content is determined by coulo-metric titration. The chloride concentrations and total pore-water concentrations, obtained earlier from the same samples by low-temperature vacuum desiccation, are used to arrive at the "original" pore-water chloride concentrations by a simple iteration procedure.
Interstitial chlorinity results obtained from Cretaceous and Jurassic strata in the Gulf of Mexico coastal areas ranged from 20 to 100 g/kg CI with reproducibility approaching ±1 %. We have also applied the technique to igneous and metamorphic bedrocks as well as ocean basalts containing 1 % water or less. Chloride values ranging from 6.7 to 20 g/kg with a reproducibility of about 5% were obtained.
Cerro Prieto Case History: Use of Wireline Logs to Characterize a Geothermal Reservoir
Authors: Halfman S. E. , Lippmann M. J. , Gilreath J. A. 
Published: December 2007

Abstract
The Cerro Prieto geothermal field is located in Baja California, Mexico, in the Salton Trough–a rift basin filled mainly with Colorado River sediments. A comprehensive wireline log analysis was undertaken as part of a multidisciplinary study of this geothermal system. It established (1) the physical properties of the various sedimentary units; (2) the depositional environment and hydrothermal alteration of the units; (3) the location, attitude, and displacement of faults; and (4) the subsurface circulation of the geothermal fluids.
Presented are the methodology that was used and the application of the results to further exploration and development of this high-temperature geothermal resource.