bluuebunny/crossref_metadata_2025 huggingface dataset:
The Water Vapor Content of Essentially Nitrogen-Free Natural Gas Saturated at Various Conditions of Temperature and Pressure
Authors: McCarthy Eugene L. , Boyd William L. , Reid Laurance S.
Published: April 2012

Proper control of the moisture content of natural gas is essential toreliable operation of gas transmission and distribution facilities servingnorthern markets. The moisture content of natural gas is usually determined bydew point measurement at the existing pressure. For any gas of constantmoisture content, the dew point varies with the pressure.

A correlation of the data of several investigators is presented in graphicalform by the authors. These data were correlated by the authors and F. M.Townsend, C. C. Tsao, M. D. Rogers, Jr., and J. A. Porter, graduate students inchemical engineering at the University of Oklahoma.

Of particular interest are the hitherto unpublished low temperature dataobserved by Wickliffe Skinner, Jr., which are included in this correlation.

Presentation of Data

The problem of interpreting water dew points, or saturation temperatures, ofnatural gas in terms of specific moisture content has increased in importanceduring the past decade because of extensive developments in the transmissionand petro-chemical phases of the natural gas industry. Virtually all gastransported to northern and eastern markets must be dehydrated to a low watervapor content to prevent hydrate formation in transmission and distributionlines and resultant interruptions in gas deliveries. Complete dehydration isrequired in certain phases of the petro-chemical industry involvinglow-temperature operations.

It is a well-known fact that the water vapor content of pure hydrocarbonvapors and their mixtures at superatmospheric pressures cannot be predictedwith accuracy by assuming validity of the ideal gas laws. Earlier interest inthe general problem was concentrated on the water vapor content of purehydrocarbons and hydrocarbon mixtures in the pressure and temperature rangescommon to gas and oil producing reservoirs in order to obtain fundamental datafor the improvement of production techniques and the furtherance of reservoirstudies. Excellent data are published for pressures ranging from atmospheric to10,000 psig and for temperatures ranging from 100? to 460'F and are found to bein close agreement. However, experimental data at high pressures andtemperatures below 100'F are comparatively limited in scope.

T.P. 2914
A Study of Reservoir Performance of the First Grubb Pool, San Miguelito Field, Ventura County, California
Authors: Glenn Wayne E.
Published: April 2012

The San Miguelito Field of Ventura County, California, lies along the coastapproximately five miles northwest of the city of Ventura. The structure is oneof several in the Ventura anticline, a series of anticlinal folds trendingnorthwest-southeast through the San Miguelito Field. The Ventura Avenue Fieldlies to the southeast along the anticline, and Padre Canyon and Rincon Fieldslie to the northwest; the series then extends beneath the Pacific Ocean.Production is obtained from the Lower Pico and Repetto formations of Plioceneage, and oil accumulation is controlled by faulting, lithology and structure.The first well in the First Grubb Pool was completed in November, 1931, and todate 48 producing wells have been drilled on the 276 productive acres.Approximately 685 ft of net pay are contained in the eight sand bodies grossing1,220'Ft of section. Production of oil to date has been 15,600,000 bbl. A gasinjection project was instigated in April, 1940, but was discontinued inSeptember, 1949.

This paper is confined to a discussion of the development and performancehistory of the First Grubb Pool of the San Miguelito Field.

Location and Geology

The San Miguelito Oil Field is located in Ventura County about five milesnorthwest of the city of Ventura along the coastal highway to Santa Barbara. Itis located within sections 23, 24, 25, and 30 of Township 3 North, Range 24West, San Bernardino Base and Meridian. Surface elevation in the field rangesfrom sea level to plus 1,200'Ft, and the terrain is extremely rugged. Thestructure is well defined on the surface and on the wall of the AmphitheatreCanyon where appears a so-called "text book" anticlinal section.

The San Miguelito structure is an asymmetrical, elongated anticline about twomiles long and three-fourths of a mile wide. The trend of the axis of theanticline is northwest-southeast. Fig. 9 illustrates the contours and majorfaults of this structure. Dips on the southwesterly flank average about 40degrees, whereas the northeasterly flank ranges from 60 to 75 degrees. Thereare several faults striking generally east and west. These faults do not appearto affect materially the area of accumulation or performance behavior. It isbelieved that accumulation was affected by steeply dipping beds and extremelylow permeability of the northeast flank of the structure.

T.P. 2951
Estimation of Interstitial Water From the Electric Log
Authors: Williams Milton
Published: April 2012

A comparison is made between the amount of interstitial water found by analysisin cores and that estimated from the resistivity curve of the electric log forthe corresponding strata of producing reservoirs. It is shown that while thedetermined and the estimated water saturations are in good agreement in somecases, this agreement may be due to a fortuitous compensation of errors.Estimates of water saturations made from the electric log by use of existingrelations should, therefore, be employed with caution. Also presented are dataon the variation of salinity of interstitial waters in reservoir sands, and onthe effect of variation of salinity and porosity on the validity of estimatesof water content made from the electric log.

Introduction

Throughout the history of electric logging there have been recurrent cyclesof optimism and pessimism as to the value of the electric log in thequantitative estimation of reservoir fluid content. The very early days ofelectric logging were an optimistic period, in which there was widespread faithin the ability of the resistivity curve to reflect fluid content, and in theability of the potential curve to indicate textural characteristics. In timethe accumulation of exceptions to this idealistic behavior brought about ageneral disillusionment, and caused the more pessimistic of those dealing withelectric logs to believe that the sole importance of the log lay instratigraphic correlation.

Within the last several years optimism as to the quantitative use of theelectric log has been revived, primarily as the result of the stimulating workof G. E. Archie on the estimation of interstitial water in sands fromresistivity data. Even though the general trend of thought on the quantitativevalue of the electric log reflects optimism, it is inevitable that there aresome widely divergent opinions of the validity of quantitative estimates basedon the electric log.

T.P. 2936
The Effect on Well Productivity of Formation Penetration Beyond Perforated Casing
Authors: McDowell James M. , Muskat Morris
Published: April 2012

A report is given of electrical analog experiments on the effect of casingperforation completions on well productivity for ideal uniform reservoirs understeady state homogeneous fluid flow conditions. Graphical results are presentedfor the effect of perforations of different densities and various degrees ofpenetration into the formation surrounding the casing or cement sheath. Thelatter range from perforations which terminate flush with the casing to thosewhich extend into the formation a distance equal to the casing diameter. Forthe special case where the perforations terminate immediately beyond the casingwith semi-spherical protrusions the electrical analog results correct andsupersede previously reported theoretical calculations. It is found that thepenetration of the perforations into the surrounding productive section may soincrease the resultant productivity as to approach or even exceed that for openhole completions.

Introduction

A theoretical analysis of the effect of casing perforation on well completion, without additional penetration of the formation, was reported several yearsago. In this treatment the perforations were represented by mathematical sinksand no explicit account was taken of the imperviousness to flow of the casingin which the perforations were made. This procedure was justified byconsideration of the mutual interference between the sinks, which seemed toindicate that the analytical method automatically eliminated flow across thecasing radius between the perforations. However, both further theoreticalinvestigation and the electrical analog measurements described below showedthat this assumption in the previously developed theory was not valid and thatthe calculated well capacities would considerably exceed the correctvalues.

Even if this simplifying assumption were retained the generalization of thetheory to situations where the perforations extend into the producing formationwould be extremely difficult. On the other hand, the electrolytic model analogof this type of steady-state homogenous fluid system is, in principle, sosimple that it has not been worthwhile to attempt to develop the exact analysiseven for the more limited case of strict casing perforation. The whole problemhas therefore been studied anew by electrical models to cover the range fromholes in the casing which terminate flush with the casing surface to such asextend into the surrounding rock to a depth equal to the casing diameter.

T.P. 2891
Phase Equilibria in Hydrocarbon-Water Systems II - The Solubility of Ethane in Water at Pressures to 10,000 psi
Authors: Culberson O.L. , McKetta J.J.
Published: April 2012

A preliminary investigation was made to determine the time required to attainequilibrium within the equilibrium cell for this system.

Experimental and smoothed data are presented for the solubility of ethane inwater for temperatures of 100', 160', 220', 280' and 340'F at pressures to10,000 psia.

The minimum solubility phenomenon disappears at 10,000 psia within thistemperature range.

As a continuation of the investigation of the behavior of hydrocarbon-watersystems, the experimental data on the solubility of ethane in water have beenextended to 10,000 psia. The experimental apparatus, technique, materials, andanalytical methods are essentially the same as previously reported.

Time-Concentration Study

Prior to the initial determinations of solubility in the ethane-water system, it was desired to establish the time necessary to agitate the liquid and vapor at equilibrium temperature andpressure in order to have equilibrium between the phases. This was done bybringing the equilibrium cell to the equilibrium temperature, charging it withethane to a pressure of 800 psia, and then charging with water to a pressurewhich was the same for each time-solubility determination. The temperature ofthe determinations was 100'F and the pressure, having been 6,330 psia for thefirst determination, was maintained at this same value on each subsequentdetermination. When the water was charged to the equilibrium cell, the celltemperature departed from 100'F and a period of time averaging about 40 minuteshad to elapse before the cell came back to equilibrium temperature. During thistime, the cell and its contents were not agitated. When the system had returnedto equilibrium temperature, agitation was started and timing was begun. Theresults of the time-solubility determinations are given in Table I. Readingdown a column in Table I, the figures represent respectively: the time ofagitation for the particular run; the time at which water was charged to thecell, taken as zero; the time elapsing after charging the water and until thecell returned to equilibrium temperature where agitation was begun; the hoursrelative to zero time elapsing before agitation was stopped; and the solubilitydetermined for the particular run. Since the ethane and water were in contactduring the period when the temperature was returning to the equilibriumtemperature, the time measured against the solubility values determined is nota true measure. Considerable diffusion undoubtedly occurred under the pressuresinvolved; however, the technique used was necessary in view of the fact thatfor the shorter runs, the system may not have been at equilibrium temperaturewhen the desired time had elapsed. From Table I it may be seen that equilibriumwas attained within one hour after agitation was begun.

T.P. 2932
Performance of the Lower Pawelek Reservoir, Falls City Field, Karnes County, Texas
Authors: Crutchfield John W. , Bowers Emil F.
Published: April 2012

This paper presents the initial results of a pressure maintenance by waterreturn project in the Lower Pawelek reservoir of the Falls City Field, KarnesCounty, Southwest Texas. Production is from the Lower Wilcox section at anaverage depth of 6,030'Ft on the downthrown side of a "down to thecoast" fault. Of particular interest is that the reservoir oil is highgravity and low viscosity but far undersaturated with gas at the originalreservoir pressure and temperature. The early pressure and production historyindicated only a partial or limited water drive, and this fact, coupled withthe characteristics of the reservoir fluid and artificial lifting problems, made advisable the water injection program to maintain reservoirpressure.

The paper includes a description of the reservoir and reservoir fluids, thepressure and production history, a description of the water injectionfacilities, and the results of reservoir calculations involving Hurst'sunsteady state flow and the material balance equations for calculation of waterinflux and prediction of the pressure-production relationship at various ratesof withdrawal.

The reservoir calculations and initial field results indicate that reservoirpressures in excess of 85 per cent of original pressure can be maintained bycontrol of water injection even at very high rates of production.

Introduction

The purpose of this paper is to report the initial results of a pressuremaintenance by water return program in the Lower Pawelek reservoir, Falls CityField, Karnes County, Texas, and to calculate an empirical relationship betweenpressure and production in this limited or partial water drive reservoir.

Discussion

Location

The Falls City Field (Fig. 1) is located two miles north of the town of FallsCity in Karnes County, Texas, and is approximately 50 miles south-southeast ofSan Antonio on U. S. Highway 181.

Discovery and Development

The initial block of leases was taken after a surface geological surveyidentified a major east-west fault and closure on the south or downthrownsection. The discovery well, Southern Minerals Corporation's Joe F. Bartosch 1, was completed at 4,650'Ft in the Lower Bartosch sand in December, 1944.Drilling was continuous until December, 1946, and resulted in the discovery of12 oil reservoirs between 4,600 and 6,050'Ft in the Middle and Lower Wilcoxformations.

T.P. 2937
Correlation of Bottom Hole Sample Data
Authors: Borden Guy , Rzasa Michael J.
Published: April 2012

Laboratory data on bubble point pressures and reservoir volume factors havebeen correlated as functions of solution gas-oil ratio, calculated gas gravityof the pentanes-and-lighter fraction of the entire fluid, differential residualoil gravity, and reservoir temperatures.

Introduction

Several correlations of crude oil properties have appeared in theliterature.

D. L. Katz in 1942 presented five methods of predicting oil shrinkage, thesebeing of decreasing accuracy for decreasing amounts of informationavailable.

M. B. Standing in 1947 published three correlations of laboratory flashvaporization data of California crudes. From values of GOR (gas-oil ratio), gasgravity, liquid gravity, and temperature, his correlations will predict bubblepoint pressure, formation volumes of bubble point liquids, and two-phaseformation volumes.

Curtis and Brinkley in 1949 presented several correlations. From the gas-oilratio, an approximation of reservoir volume factor and barrels of condensaterecoverable per barrel of reservoir space may be obtained; along with liquidgravity and reservoir temperature, the GOR will allow prediction of bubblepoint pressure. These last correlations seem to be more qualitative thanquantitative.

Generally, laboratory bottom hole sample tests furnish information on solutiongas-oil ratios, residual oil gravities, bubble point pressures, viscosities ofoils, liquid shrinkages, and occasionally gas gravities. Each of these data hasits own applications and use in reservoir engineering calculations. Theparticular uses of correlated bottom hole sample data are found inProviding a basis for obtaining estimates of formation crude propertiesin fields where bottom hole sampling is impractical or impossible.Greatly reducing the time in obtaining the desired information.Determining the applicability of the results from various bottom holesamples to particular field problems.Avoiding, in many cases, the uncertainties of sampling by replacing it withan element over which greater control can be exercised.Permitting use of preliminary field data in application of productionprocedures before a bottom hole sample can be obtained and analyzed in thelaboratory.Serving as a check on data which may appear out of line.Estimating for a particular type crude the appropriate equilibriumconstants by working backward from the bubble point pressure.Estimating original or other past history properties of reservoirs thatwere not sampled in the past.

T.P. 2931
The Effect of Permeability Stratification in Complete Water-Drive Systems
Authors: Muskat Morris
Published: April 2012

A theory is presented for calculating the performance history of completewater-drive systems producing from idealized stratified formations. The generalequations are applied to systems where the permeability stratification iseither of the exponential or linear type. Calculations were carried through fordifferent degrees of permeability stratification, but with special emphasis onthe effect of the mobility ratio between the produced oil and the invadingwater on the resultant performance. These results are also expressedgraphically as curves for the initial water breakthrough recovery, for thedifferent degrees of stratification, as a function of the mobility ratio, andof the composition of the produced fluid stream as a function of the cumulativeoil recovery. For several typical cases the latter has also been plotted as afunction of the cumulative oil and water through-flow. The general result isthat when the mobility of the oil is lower than that of the invading water thechannelling tendency resulting from the permeability stratification becomesaggravated as the higher permeability zones become flooded out. Situations ofthis type would obtain when producing low gravity or highly viscous oils.Conversely, if the mobility of the oil is high compared to that of the invadingwater, the flooding of the high permeability zones will lead to a retarding andchoking effect, and the gross bypassing phenomena will be partially suppressed.These conditions would correspond to those of flooding high gravity or lowviscosity oils. A discussion is given of the various basic assumptions made inthe analysis, including that of ignoring the stripping phase of the productionhistory as implied by relative permeability concepts.

Introduction

The physical ultimate recoveries from oil reservoirs are basicallydetermined and limited by the physical oil displacement processes associatedwith the reservoir producing mechanism. In practice, however, the economicultimate recoveries are further limited by the mobility of the reservoir fluidsand the uniformity and continuity of the producing formation. In fact, it isthe differential depletion between the component parts of the compositereservoir which ultimately determines the total recovery at the time of fieldabandonment.

T.P. 2894
Stainless Steel Containers for Laboratory Drilling Mud Test Work
Authors: Lilienthal W.B.
Published: April 2012

A considerable saving in time and money has been effected by use of aspecially designed stainless steel container for laboratory drilling mud testwork. This container involves use of a standard tall-form stainless steelbeaker for service in which the mud sample is heated to an elevated temperatureand maintained there for protracted periods of time, while undergoing agitationto facilitate mixing of mud components. Agitation is accomplished by rotatingthe filled containers on motor-driven rollers within an oven. Several porcelainballs are generally placed in the containers to further improveagitation.

Soft glass containers (Mason jars) were used in this service in early work, andwere found to be unsuitable for the following reasons:Poor resistance to thermal shock.Containers could withstand only relatively low pressures.Accidental breakage in handling.Chemical deterioration and subsequent mud contamination from reaction ofhigh pH muds with the glass at elevated temperatures.

Pyrex containers were also considered, but, inasmuch as they providedimprovement only in items 1 and 4 listed above the additional cost was notbelieved to be justified.

A scale drawing of the container is shown in the figure illustrating details incross-section. A pressed stainless steel lid was fabricated to match the rollededge of the beaker top, and male and female screwed connections external to thecontainer were made up to complete the closure with the O-ring used as a gasketbetween the lid and beaker.

T.N. 56
Interpretation of Capillary Pressure Data
Authors: Purcell W.R.
Published: April 2012

In a previous technical note by Walter Rose, evidence is offered in supportof the contention that "the possibility of describing oil recovery featuresin terms of capillary pressure phenomena has not been establishedentirely." It is not the purpose of this note to present further discussionof this possibility but rather to point out that the argument presented theredoes not appear to be generally valid.

In the cited note reference is made to the experiments of Welge wherein it wasshown that when water was displaced by oil from a core the pressure in thewater phase was less than in the oil phase but that when this oil was thenproduced by water drive the pressure in the water phase was greater than in theoil phase. Rose has concluded from these observations that conditions of staticequilibrium did not obtain since the fluid saturations were such that phasediscontinuities seemed unlikely. The argument from which this conclusion wasdrawn is based on the contention that "the pressure is always greatest inthe non-wetting phase at each static interstitial interface of contact with thewetting phase." This premise appears to have been reached from aconsideration of capillary phenomena in cylindrical tubes, although it may alsohold for other types of pore geometry, but as will be shown below it does nothold for all pore shapes and hence is not generally applicable.

Since the pore structure of porous media such as reservoir rocks is in generalso complex as to defy exact description, it is undoubtedly of great value toestablish a model in terms of pore shapes of known geometry, provided of coursethat the limitations of the model are recognized. That the limitations of thecapillary, or cylindrical tube model have not always been fully recognized willbe evident from the following discussion of a pore of different shape but onewhich may as logically be considered as the capillary tube.

T.N. 60
A Study of the Dornick Hills-Springer Sand Reservoir, Velma Pool, Oklahoma
Authors: Davis W.B.
Published: April 2012

This paper presents a summary of the results of a study of the DornickHills-Springer sand reservoir of the Velma Pool, Stephens County, Oklahoma. Thedata are of interest because this type of reservoir is unusual in themid-continent area.

The reservoir is characterized by very steep dips and a relatively thickproducing section. Its up-dip productive limit is defined by truncation of theproductive sands, and the down-dip limit is defined by deterioration of sandquality rather than by the presence of an oil-water contact. The crude oil isof 29' API gravity, is relatively viscous and was saturated with dissolved gasat the original reservoir pressure.

Consideration of the physical characteristics of the reservoir indicatesthat natural water encroachment will be negligible, and that the producingmechanism will be a dissolved gas drive augmented by gravity drainage.Performance to date tends to confirm this.

Introduction

It is the purpose of this paper to present some of the features of theDornick Hills - Springer sand reservoir which are unusual in mid-continentoperations. The study was undertaken in an attempt to define the producingmechanism or mechanisms that will control reservoir performance, as an aid indetermining well completion and production practices.

Geology

The reservoir under consideration is a series of sand bodies ofPennsylvanian age found in the Lower Dornick Hills and/or Springer formations.For the purpose of this paper, the sand series is referred to as the DornickHills-Springer sand.

This sand series lies on the northeast flank of the Velma anticline, and dipsvery sharply to the northeast in TWP 1S-5W, the average dip being about 45'.However, as shown in Fig. 1, the trend of the pool swings eastward in TWP 1S-4Wwith a coincident decrease in dip angle. In this portion of the pool theaverage dip is about 25'.

T.P. 2999
Capillary Pressure Investigations
Authors: Brown Harry W.
Published: April 2012

This paper presents results of static capillary pressure measurements madeboth by the restored-state and by the mercury-injection methods, and of dynamiccapillary pressure measurements made by the Hassler technique.

The results indicate a variation from sample to sample of the factor used toconvert capillary pressure obtained by mercury injection to those applicable toa water-gas system. Static capillary pressures measured by the restored-statemethod were found to be in close agreement with dynamic capillary pressures, indicating that data obtained from static measurements may be utilized withconfidence in the solution of dynamic problems of fluid flow.

Experimental data are presented on the use of "J-curves" for thecorrelation of capillary pressure-saturation relations for a number of coresfrom a particular geologic formation. It is shown that the correlation wasimproved in some cases by restricting it to certain lithologicclassifications.

Introduction

The Meaning and Importance of Capillary Pressure

The coexistence of two or more immiscible fluids within the voids of aporous medium, such as reservoir rock, gives rise to capillary forces. Becauseof the interfacial tension existing at the boundary between two immisciblefluids in a pore space, the interface is curved, and there is a pressuredifference across the interface. This pressure difference is termed thecapillary pressure.

The magnitude of the capillary pressure between two immiscible fluids whichtogether fill a porous medium depends upon several factors: the texturalproperties of the medium, the wettability of the medium, the interfacialtension between the fluids, the respective saturations of the fluids, and themanner in which these saturations are attained. For a given pair of immisciblefluids in a particular sample of reservoir rock, the capillary pressure is aunique function of the fluid saturation, provided that the saturation of thefluid which wets the rock has previously been decreased unidirectionally froman initially complete saturation.

T.P. 3025
Relative Permeability to Liquid in Liquid-Gas Systems
Authors: Rapoport L.A. , Leas W.J.
Published: April 2012

As a preliminary, consideration is given to the conventional definition ofrelative permeability and to the conditions governing the simultaneous flow ofoil and gas through porous media.

For the conditions of flow prevailing throughout most of a gas drivereservoir, the oil and gas can reasonably be supposed to be in capillaryequilibrium with each other. Under these conditions, and these conditions only, the relative permeability to liquid can be expressed as a function ofsaturation. The relative permeability to liquid in that case is dependent uponthe distribution of fluids which itself is shown to be related to the capillarypressure, and, in turn, to the saturation. As a consequence, relativepermeability to liquid can be expressed in terms of the volume and surface areaof a network of liquid channels bounded by the rock and the gas phase. Whilethe volume of this network can be evaluated accurately, the surface areacannot. However, for any such volume, maximum and minimum values of thecorresponding surface area can be calculated from capillary pressure data. Itis then possible to establish for any saturation the limits within which thevalue of the relative permeability to liquid must lie.

As a consequence of the theoretical development, the validity of anexperimental method for measuring relative permeability to liquid whichutilizes a stationary gas phase is demonstrated. In this method capillarybarriers are cemented to the ends of the core sample to permit the maintenanceof capillary equilibrium between the two phases. At the same time, thisprocedure eliminates undesirable secondary phenomena such as end effects, fissure effects, etc., the presence of which adversely affect the results ofother laboratory methods.

The results obtained by theoretical calculations, and experimentally, arediscussed. In view of the overall precision that can presently be obtained inreservoir calculations, the agreement between the calculated and measuredrelative permeability to liquid data can be considered satisfactory.

In conclusion, for reasons of economy and simplicity, the procedure ofcalculating limiting relative permeability to liquid curves from capillarypressure data is indicated for general engineering purposes. It is shown thatthe above procedure can easily be extended to the cases where connate water ispresent. Its use for reservoir studies is particularly recommended inconjunction with the method for measuring relative permeability to gas whichsimultaneously yields the capillary pressure data necessary for thecalculations.

T.P. 3021
Experimental Investigation of Factors Affecting Laboratory Relative Permeability Measurements
Authors: Geffen T.M. , Owens W.W. , Parrish D.R. , Morse R.A.
Published: April 2012

Laboratory studies of several factors affecting measurements of relativepermeability were made using the three-section plastic-covered core technique.Results show that the core assembly, properly constructed, will perform as asingle unit, and that the testing technique will, under suitable conditions ofpressure gradient, gas expansion, and migration of partial water saturation, permit measurement of flow characteristics not affected by technique.Wettability equilibrium is readily established in cores exhibiting strongwetting preference to water or oil when initially saturated with water.Laboratory tests must be conducted so that saturation changes represent thosethat occur in the reservoir. Immediate implications of saturation history arethat the possibility exists of increasing the displacement efficiency ofsolution gas drive reservoirs over the natural process, andresidual gassaturations following water flooding in gas or gas condensate reservoirs willbe 15 to 50 per cent pore space rather than 1 to 11 per cent as generallybelieved.

Introduction

Solutions of petroleum reservoir problems pertaining to productionperformance require the use of true relative permeability characteristics. Thisrelationship of fluid conductivity and saturation has been obtained byreservoir engineers in four ways, namely:From past gross reservoir performance and the extrapolation of this databased on experience,By using published fluid flow relationships obtained in laboratory studieson general type porous materials,By attempting a mathematical derivation of flow behavior, using someexperimentally obtained characteristics of reservoir rocks, andBy laboratory flow tests using representative rock samples of areservoir.

The first three methods listed above have shortcomings which make their uselimited or questionable. Production characteristics of only certain processesare obtained from field data and these are not available at the beginning of areservoir's producing life, at which time they are desirable. It is fortuitousif general fluid flow characteristics obtained experimentally have accurateapplication to specific field problems. Also, it is felt that at this timethere is not sufficient knowledge of the flow behavior of oil, water, and gasin porous materials to enable applicable analytical description of this to bemade based on other measured rock characteristics.

Measurement of relative permeability in the laboratory offers the only directmethod subject to adequate checking for determination of flow characteristicsapplicable to field problems. Primarily, this paper deals with laboratoryexperiments to establish the effects of several factors on the measurement ofrelative permeability and the practical significance of this knowledge.

T.P. 3053
The Shuler Jones Sand Pool; Nine Years of Unitized Pressure-Maintenance Operations
Authors: Tarner Jack , Evans W.R. , Kaveler H.H.
Published: April 2012

The geological features, development history and engineering detail of theShuler Field and the results of approximately two years of unitized operationof the Shuler Jones Sand Pool, were discussed in a prior publication. Thepurpose of this paper is to present the results of pressure maintenance in theShuler Jones Sand Pool after nine years of unit operation.

General Information

The Shuler Jones Sand Pool is located in and about Section 18, Township 18South, Range 17 West, Union County, Ark. The pool was discovered in September,1937, unitized in February, 1941, and subjected to gas injection operations inJuly, 1941. Water was first returned to the reservoir in July, 1944.

The reservoir is an anticlinal trap covering about 4,000 acres. The 154,000acre-ft of sandstone initially consisted of approximately 150,000 acre-ft ofproductive oil zone and 4,000 acre-ft of gas-cap. The average depth ofproduction is 7,400'Ft. Maximum closure of the reservoir is 135 ft and the oilcolumn lies between a gas-oil contact at -7,270'Ft and a water-oil contact at-7,370 to -7,380'Ft. The field is approximately four miles long, east and west, and one and one-half miles wide.

The sand grains are angular and vary from fine to medium size. The porosityof the sandstone averages 20.2 per cent. The specific permeability averages 400md. Some zones have as high as 30 per cent porosity and specific permeabilityof 4,000 md. The reservoir rock is not uniform in character but consists ofsandstone zones interspersed with shale. The variation in rock characteristicsis evident in the electric log and core analyses presented in the originalpublication. Asphalt present in the pore space of the sandstone limited thereservoir to the southeast and apparently blocked any encroachment of waterfrom that direction.

The initial reservoir pressure at a subsea depth of 7,300'Ft was 3,520 psi.The reservoir temperature was 198?F. Initially, the solution gas volume was 765cu ft per bbl and the reservoir volume factor was 1.45. The equation for thegas volume factor presented is based on a direct measurement of a sample of thegas and is a correction of that used in the original paper.

The gravity of the oil produced is from 32 to 34? API.

T.P. 3054
Plastic Flow Properties of Drilling Fluids - Measurement and Application
Authors: Melrose J.C. , Lilienthal W.B.
Published: April 2012

The application of Bingham's law to the behavior of drilling fluids in arotational viscometer permits the expression of viscometric data in terms ofplastic viscosity and yield value, the flow properties of a plastic fluid. Acommercially available rotational viscometer is described, and when modified toa multispeed type viscometer, is shown to provide a simple and convenientinstrument for the measurement of these properties both in the laboratory andin the field. The data obtained are shown to be useful in defining andunderstanding mud control problems relating to chemical treatment and to thehydrodynamic behavior of muds.

Introduction

The highly complex drilling fluids which are required for deep drillingoften give rise to new and unusual mud control problems. Rapid and economicsolutions to these problems may require, on the one hand, better understandingof the changes which contaminants and chemical treating agents produce in thecolloidal and inert solids of the mud, or, on the other hand, closer control ofthe hydrodynamic behavior of the mud. The latter objective obviously can beachieved only if a correct rheological analysis of the flow behavior ofdrilling muds is available and if this is accompanied by the appropriaterheological measurements. The purpose of this paper is to describe suchmeasurements in the field, and to show how the resulting data can be of valuein solving difficult mud control problems.

It is now generally recognized that Bingham's law of plastic flow can beutilized in describing the hydrodynamic behavior of drilling fluids in thenon-turbulent flow range. Beck, Nuss, and Dunn have recently applied this lawto the flow of mud in small pipes, and Rogers has reviewed the rather extensiveliterature on this subject. So far, however, the use of Bingham's law has beenrestricted to the analysis of mud flow in pipes or capillary tubes, and it hasnot been directly applied to the flow in rotational viscometers. In the work tobe reported, the Reiner-Riwlin equation for the flow of a plastic fluid in arotational viscometer has been utilized to permit the expression of multispeedviscometric data in terms of plastic viscosity and yield value, the twoabsolute flow properties of a plastic fluid.

T.P. 3061
Relative Permeability Studies
Authors: Fatt I. , Dykstra H.
Published: April 2012

Relative wetting phase permeabilities calculated from capillarypressure-saturation data are compared with measured relative permeability data.The equation relating relative permeability to capillary pressure-saturationdata is derived by assuming that a porous medium is analogous to a bundle ofcapillary tubes. The equation includes a term to correct for the differencebetween fluid path length and length of core. Relative oil permeability data inthe water-oil-gas system are presented, and it is shown that if the water isconsidered part of the rock matrix, the relative oil permeability curve istypical of a wetting phase relative permeability curve. Apparatus for measuringtwo and three-phase relative permeabilities are described.

Introduction

The difficulty in measuring relative permeability of cores has made itdesirable to have a correlation between relative permeability and some moreeasily measured property of porous media. Such an easily measured property isthe capillary pressure-saturation relation.

In the past there has been a tendency to separate the capillary pressureconcept from the very complex pore geometry and to consider that the capillarypressure-saturation curve gives only some characteristic distribution ofinterfacial curvature between two fluids. Recently, however, it has beenrealized that if capillary pressure data are to yield information concerningpore size distribution and fluid flow in porous media, the pore must be assumedto have a simple shape such as a cylinder or a sphere.

Childs and George showed that relative water permeability could becalculated from the capillary pressure-water saturation curve by assuming thatthe pores are cylinders in which the fluid flowing obeys Poiseuille's Law, andthat the capillary pressure curve indicated the size and number of pores.Purcell derived an equation relating the permeability of a porous medium to thecapillary pressure curve by assuming the porous medium to be analogous to abundle of capillary tubes. Gates and Lietz calculated relative permeability byan equation derived from Purcell's equation.

In this paper an equation is derived giving the relative water permeability asa function of water saturation by assuming that the core sample can berepresented by a bundle of capillary tubes in which the fluid path length isnot the same as the bulk length, and in which the fluid path length varies withsaturation.

T.P. 3078
Phase Equilibria In Hydrocarbon-Water Systems IV - Vapor-Liquid Equilibrium Constants in the Methane-Water and Ethane-Water Systems
Authors: Culberson O.L. , McKetta J.J.
Published: April 2012

Introduction

The equilibrium constants for methane and for water, and for ethane andwater have been calculated from experimental data for the two binary systems.These constants are for the two-phase systems for the temperature range of 100?to 340'F and the pressure range of 200 to 10,000 psia.

The constants for ethane are greater than those for methane. Equilibriumconstants for a natural gas from a natural gas-water system are about the sameas those for methane. Equilibrium constants for water in all three systems arevery nearly the same over the greater part of the range of temperatures andpressures studied.

In ideal solutions, the vapor-liquid equilibrium constants for a componentshould be the same in all such solutions at a given temperature and pressure.Few solutions are ideal, and consequently the use of generalized constantsoften leads to error in situations where they do not actually apply. Indecidedly non-ideal systems, it is desirable to have equilibrium constant datafor the specific system.

Vaporization equilibrium constants may be calculated either by thermodynamicmethods or from experimental vapor-liquid equilibrium data.

(Equation 1)

Equilibrium constants calculated from Equation (1) have been found to haveonly limited agreement with experimental values, even though the solutions forwhich they were calculated approached ideality. If the more volatile componentis at a temperature above its critical, the accuracy of the equilibriumconstant for the component is made more doubtful by the use of the vaporpressure term under such conditions. In order to make the thermodynamiccalculation on a component above its critical temperature, one must resort toone of the empirical methods of extrapolation of the vapor pressure toconditions above its critical point. Application of the thermodynamicequilibrium constant then to the methane-water or the ethane-water systemswould be risky since the systems are non-ideal, and the methane and ethane areabove their critical in most petroleum operations.

T.P. 3201
Measuring the Water Vapor Content of Gases Dehydrated by Triethylene Glycol
Authors: Politziner Irwin , Townsend F.M. , Reid L.S.
Published: April 2012

Recently published data indicate that the water vapor content of a gas, asdetermined by dew point measurement, is inaccurate when the gas has beendehydrated with diethylene glycol. Water vapor contents and dew pointmeasurements of gases dehydrated with triethylene glycol have been obtained inthis investigation in order to determine the magnitude of a similar error, ifone exists.

Experimental data show a very low concentration of triethylene glycol vaporin gases dehydrated at atmospheric temperatures and pressures ranging from 500to 2,500 psia, and that the accuracy of dew point measurements is not impairedby the presence of triethylene glycol vapor.

Introduction

Nearly all natural gas transported by pipe line to northern and easternmarkets must be dehydrated to a low residual moisture content in order toassure maximum transmission efficiency and continuous delivery under peak loadconditions. Without dehydration, water vapor often condenses in pipe lines inquantities sufficient to restrict the flow and, under low atmospherictemperature conditions, gas hydrates may form and plug gathering, transmissionand distribution facilities.

Gas may be dehydrated to pipe line specifications by a number of methods.The most widely used methods areadsorption of water vapor on a soliddessicant such as activated bauxite, alumina or silica gel,by absorptionof water vapor by either diethylene or triethylene glycol-water solutions ofhigh glycol concentration, andby simultaneous expansion-refrigeration ofvery high pressure gas in which gas hydrates are purposely formed and thenquickly decomposed.

Of these three fundamental methods, the adsorption andabsorption processes provide the bulk of the dehydrated gas moving to market atthe present time. The expansion-refrigeration process, a relatively newdevelopment, is gaining in favor because of its simplicity but is sharplylimited in its application by available differentials between source andgathering system pressures.

T.P. 3200
A New Technique for the Measurement of the Formation Factors and Resistivity Indices of Porous Media
Authors: Morgan F. , Wyllie M.R.J. , Fulton P.F.
Published: April 2012

The importance of formation factor, F, not only in electric logging but as afundamental rock parameter has recently been stressed. The desirability ofinvestigating the range of variation of the resistivity index exponent, n, inthe relationship I = Sw-n, where I is the resistivity index and Sw the watersaturation as a fraction of the void volume of a porous medium, has also beenurged. The magnitude and variation of n with saturation and rock texture is asubject not only of theoretical interest but also one of prime importance inthe interpretation of electric logs.

A simple technique has recently been developed which enables both F and n tobe measured with high accuracy and which may also find acceptance as aconvenient method for the determination of irreducible saturation attainment inthe restored state method of core analysis.

Experience has taught that reproducible measurements of F are possible onlyif the resistance measuring electrodes are so arranged with respect to a planeface on a porous medium that they are able to make electrical contact withsubstantially all entry pores in that plane. In practice this may be achievedby using a platinized-platinum gauze electrode backed by some absorbentmaterial (such as felt) which has been saturated with a fluid identical withthat used to saturate the porous medium. Application of pressure to theelectrode and absorbent material then forces the gauze against the plane faceof the porous medium and simultaneously squeezes saline solution through themeshes of the gauze. By this means the electrode is in continuous aqueouscontact with all pores and satisfactory and reproducible low resistance contactwith the porous medium is achieved.

Clearly this method, although satisfactory for measurements of F, cannot beapplied to the making of continuous resistance measurements on a porous mediumwhile capillary pressure desaturation is being carried out. However, acceptingthe principle that for satisfactory results electrical contact must be madebetween a measuring electrode and all pores adjacent to that electrode, methodsof bringing electrodes into intimate contact with the surfaces of porous mediawere investigated.

T.N. 65