bluuebunny/crossref_metadata_2025 huggingface dataset:
Economic Equilibrium in Petroleum Refining Operations
Authors: Fitz Gerald Norman
Published: June 2014

The lack of a continuous operating balance in petroleum refining, which isanalyzed in this paper, is by no means a feature solely of this division of theoil industry. Serious disequilibria of a capital as well as an operating natureexist both in the producing and marketing departments, while problems in theformer and to some degree the latter are complicated by political involvements.Attention has previously been directed to the unstabilizing influence ofpresent proration formulas in stimulating unnecessary drilling. Whileequilibrium in petroleum refining operations has been fairly well maintained inthe past decade, examination of departures may prove fruitful.

Economic analysis is the application of time and motion study to thefunctioning of management, rather than labor. Properly applied it may revealchanges in policies that would increase the utility of the properties andfacilities of the industry for stockholders, employees and the public, whilecontributing a stabilizing influence to the general economy. The study ofeconomic equilibrium is essentially one of measurement and interpretation, requiring adequate data and the development of a technique of analysis thatemploys statistical and mathematical methods as a supplement to the broaddescriptive phase of economics.

Economic equilibrium in petroleum refining is a dual concept. It embracesboth the over-all balance between total storage and total demand for majorproducts and the internal balance between the demands and inventories of thevarious products. The latter is the more complex of the two for it is concernedwith proportionating the supplies of the several products stemming from thejoint source to the demands for the individual products which are subject towide variations. All the products are essentially nondurable goods, and theyare used both by producers and consumers but in varying proportions. Motor fuelis very largely a consumer's good, while residual fuel oil is almost entirely aproducer's good, the other products falling between these extremes.

T.P. 1030
Core Analysis
Authors: Pyle Howard C. , Sherborne John E.
Published: June 2014

Core analysis is a recent development in the field of petroleum technology.The earliest work on this subject was done in connection with evaluating andplanning secondary oil recovery by water-flooding. Present-day analysis ofsands of flush fields requires new and independent interpretations of the dataprovided by cored material. Particular attention is being paid to thedevelopment of rapid, routine methods for measuring physical characteristics ofsandstone, such as permeability, porosity and grain size, as well as the sand's fluid content.

Permeability may be defined as the fluid-passing capacity of a rock.

For a sandstone to be permeable it must be possible to pass a measurablequantity of fluid through the material in a finite period of time. The commonunit of permeability is the darcy, which may be defined as the rate of viscousflow, in milliliters per second, of a fluid of one centipoise viscosity througha porous medium having a cross section of one square centimeter, under apressure gradient of one atmosphere (76.0 cm. Hg) per centimeter. 1 Forconvenience the subunit millidarcy, or one-thousandth darcy, is often used.Porosity is defined as the fluid-containing capacity of a rock and is usuallyexpressed as a percentage ratio of the total pore volume to the rock or bulkvolume. Since measurement of only the effective or communicating pore volume isoften made, porosities are distinguished as total or effective. Net effectiveporosity is defined as the net pore volume available for oil and gas. Oil andwater content of sand is measured and expressed either as the percentagesaturation of the total pores or of the bulk rock. The oil content may also beexpressed as the percentage saturation of the net effective pores.

In connection with water-flooding, methods of core analysis were developed tofurnish data that could be used in determining the quantity of recoverable oil, and the probable rates at which various sands or divisions of a sand open tothe wells would take water or produce oil. In flush fields, the analytical dataare used to predict the productivity of a cored interval.

T.P. 1024
A New Device for Determining Porosity by the Gas-expansion Method
Authors: Stevens A.B.
Published: June 2014

In the calculation of oil and gas reserves by volumetric methods, it isnecessary to know the volume of the reservoir available for the storage of theoil or gas. To obtain this information, a number of methods for determiningboth total and effective porosity of reservoir rocks are used. For thedetermination of the total porosity, or the porosity that considers all of thepore spaces, connected and isolated, the Russell and the Melcher-Nuttingmethods are the best known and most widely used in the petroleum industry.These methods have disadvantages in that they give the total porosity of thesamples and in that the samples are reduced to grain size in the determination.In many sands there may be little or no difference between total and effectiveporosity but in other sands there may be considerable difference between thetwo. For the estimation of oil and gas reserves the effective porosity of thereservoir rock always should be used.

Of the methods that have been developed for the determination of theeffective porosity of reservoir rocks, or the porosity that considers onlythose pore spaces that are connected, the best known are the so-called Boyle'slaw and the Washburn-Bunting methods. The Washburn- Bunting method is probablythe most widely used because it gives effective porosity, it is rapid, and theapparatus is inexpensive. This method employs a special porosimeter in whichthe core sample is placed in direct contact with mercury. This method hasdisadvantages in that, as a result of the high vacuum created in the porespaces, mercury is drawn into the openings, making it impossible to use thesample for a check determination and also ruining the sample for any furthertest, such as permeability. The purpose of this paper is to describe anapparatus employing the same principle as the Washburn-Bunting method but sodesigned that the core sample does not come in contact with the mercury in theporosimeter.

T.P. 1061
Bottom-hole Measurements in Pumping Wells
Authors: Jakosky J.J.
Published: June 2014

The fundamental hydrodynamic principles governing the production of oil fromwells have been carefully studied and evaluated by many investigators. Theseprior studies are quite complete and cover virtually the entire field of oilproduction and recovery. One of the most important measurements in productionstudies is that of the bottom-hole pressure at various rates of production. 2It is the purpose of this paper to outline the technique and economics offluid-level measurements as applied to pumping wells and to review brieflyother methods for obtaining bottom-hole data.

The applications of bottom-hole pressure or fluid-level measurements are basedon simple hydrodynamic principles. Under equilibrium conditions,Pbh = hd + pg + pch whenPbh = bottom-hole pressure, lb. per sq. in.absolute,h = height of fluid in well, ft.d = average fluid density, lb. per sq. in. per foot,pg = weight of section of gas column 1 in. square from fluid level tocasinghead,Pch = casinghead pressure, lb. per sq. in. absolute.

In words, equation 1 states that the bottom-hole pressure is equal to theweight hd of the column of fluid plus the weight of the column of gas betweenthe fluid and the casinghead plus the casinghead pressure.

At moderate rates of flow, the rate of production is approximately proportionalto the difference between the reservoir, or static bottom-hole, pressure andthe flowing or producing pressure. However, at production rates approachingzero and also at high rates the proportionality may break down.

T.P. 1058
Effect of Acid Treatment upon Ultimate Recovery of Oil from Some Limestone Fields of Kansas
Authors: Heithecker R.E.
Published: June 2014

Almost every oil well drilled into limestone formations in Kansas is treatedwith hydrochloric (muriatic) acid upon completion: to increase potentialcapacity of well and thereby increase its "daily allowable" production;to shorten time required to produce recoverable oil; and to increase quantityof oil recovered ultimately from reservoir.

Acid treating marked a forward step in the producing fields of Kansas; in fact, many old limestone fields that almost had reached their economic producinglimit were "rejuvenated" with acid and their capacities to produceincreased several times. It also caused a marked increase in the ultimate oilrecovery of some old and nearly depleted fields of Kansas. The effect of theacid was due to the cleaning-out action by the acid at the face of thelimestone, the enlargement of the small drainage channels, and the apparentpenetration of the acid to previously undrained porous and saturated strata.Studies of the effects of acid were made in the Fairport field, three groups ofwells in the El Dorado field and the Shutts field. Estimation of increasedrecoveries resulting from acid in these fields and groups of wells ranged from1000 to 2400 bbl. per acre.

Limestone structures that had been tested by? drilling and found noncommercialwere later completed as commerical oil-producing formations through the use ofaoid. The Kansas City formation, Valley Center field of Kansas, is an example.Increased oil production and revenue from the old fields justified thereconditioning of equipment, which in most cases had become in poor mechanicalcondition.

The first treatment with 'hydrochloric acid of an oil well in Kansas was in October 1932, and by the end of 1937 almost 6000 wells had been treated. Manywells were treated more than once and the total number of treatments exceeded8000 by the end of 1937. Approximately 12% million gallons of acid was requiredfor these treatments.
Influence of Oil Flow on Water Content
Authors: Van Wingen Nico
Published: June 2014

Experiments performed with distilled water, unconsolidated sand and dead oilfor the purpose of determining the influence of oil flow on the water contentof sands were described. While results found are not necessarily, therefore, identical with those that would be obtained under natural petroleum reservoirconditions, the following conclusions were drawn.When oil under constant head is flowed through an unconsolidated sand, theamount of water retained in the core is inversely proportional to the specificpermeability of the core. This corroborates the view that the degree to whichoil displaces.water out of the pore space is limited by the size of thepores.For the range investigated, the displacing action of a more viscous oil ofhigher specific gravity was found to be the same as a less viscous oil, orlower specific gravity.The amount of interstitial water retained in the sand bears an inverserelationship to the pressure head of the displacing liquid.The degree of retained water saturation of the sand appears to approach 100per cent as the specific permeability approaches zero.For the higher values of specific permeability and for the pressure rangeinvestigated the remaining amount of water in the sand occupies approximately10 per cent of the pore space. This, together with the fact that the limitingoil velocity curve approaches approximately 10 per cent water saturation as anasymptote, indicates that beyond this point removal of water is achieved onlyby a stripping of the grains requiring considerable pressure drops across thesands; or by a balancing of the molecular forces.As the water saturation of the sand exceeds approximately 15 per cent of thepore volume, the permeability of the sand to oil decreases rapidly.Sands with water saturations as high as 40 per cent were found to produce100 per cent oil.
Detection of Radioactive Cement in Cased Wells
Authors: Howell Lynn G. , Frosch Alex
Published: June 2014

In a previous article we have described a technique for measuring therelative intensities of gamma rays from the radioactive elements occurringnaturally in geological formations along the walls of a borehole. The apparatusconsisted of two Geiger-Muller tubes mounted inside a pressure tight chamber.Each counter tube was coupled separately to an amplifier and a frequency meterat the surface by means of a multi-conductor cable upon which the chamber wassuspended. The output currents of the two frequency meters were recorded on aphotographic paper as the chamber was moved in the hole. These traces showedremarkable correlation with the geologic formations, as evidenced by comparisonwith commercial electrical logs. Owing to the penetrating power of the gammarays, logs may be taken in both open and cased boreholes.

The apparatus has recently been changed somewhat. One of the counter tubes hasbeen removed and a stage of amplification has been added inside the chamber.This arrangement seems to give a more favorable signal-to-noise ratio andsatisfactory logs can be now made in cased holes and also in open holes aspreviously. Briefly described, the chamber moving in the hole is made of 372-in. drill pipe and is about 10 ft. long. There is an additional extensionabout 2 ft. long at the top, inside which cable connections are made. TheGeiger-Muller tube is mounted inside the bottom end of the chamber. Above thisis the vacuum-tube amplifier with its batteries and transformer. In the toppart of the chamber, small 45-volt batteries are mounted, which in part supplythe high voltage for the counter tube. Additional voltage IS supplied from thesurface through the multi-conductor cable upon which the chamber is suspended.Also, the output of the transformer in the single-stage amplifier is coupled toanother single-stage amplifier at the surface through this cable.

T.P. 1113
Phase Diagram of a Mixture of Natural Gas and Natural Gasoline Near the Critical Conditions
Authors: Katz D.L. , Vink D.J. , David R.A.
Published: June 2014

A phase diagram showing boundary curve and quantity of liquid in thetwo-phase region was determined for a mixture of natural gas and naturalgasoline in the region of its critical conditions. The temperatures andpressures of phase measurements were in the range of 850 to 2120 F. and 1300 to2600 lb. per sq. in., respectively, with the critical conditions at 169.50 F.and 2615 lb. per sq. in. abs. Color phenomena were observed in the region ofthe boundary curve from 1020 to 1920 F. Approximate densities of thesingle-phase and two-phase regions and analysis of the system areincluded.

Boundary curves between the single-phase and the two-phase regions have beendetermined for several binary mixtures containing hydrocarbons. Theseinvestigators did not report the relative amounts of liquid and vapor withinthe two-phase region. The equilibrium values obtained from the dew-point andbubble-point data can be used to compute the lines showing percentage of liquidon the pressure-temperature phase diagram but the positions of the lines nearthe critical temperature and pressure are uncertain. Relative amounts of vaporand liquid were obtained for a gasoline and a naphtha within the two-phase areabut not in the region of the critical temperature and pressure. Thebubble-point and dew-point lines, as well as the percentage liquid lines withinthe two-phase region, were determined by visual observations in glassapparatus.

Apparatus

An arrangement of the apparatus is given in Fig. 1, showing the Jerguson gaugeA with glass windows B.

T.P. 1114
Volumetric Behavior of Isobutane
Authors: Morris W.M. , Sage B.H. , Lacey W.N.
Published: June 2014

The volumetric behavior of isobutane at temperatures below its criticaltemperature has been studied by several investigators. Seibert and Burrellmeasured the vapor pressure of isobutane from the ice point to the criticaltemperature. Dana and co-workers determined among other thermodynamicquantities the density of the saturated liquid and the saturated gas and thevapor pressure from approximately 0? to 130? F. Sage and Lacey studied a numberof the thermodynamic properties of this hydrocarbon from 70? to 250? F. Thespecific volume in the gas and liquid region was determined at pressures up to3000 lb. per sq. in. t throughout this temperature interval. In addition, thevapor pressures were measured at 30? intervals. These data taken together serveto establish the thermodynamic behavior of isobutane at temperatures between 0?and 250? F. with reasonable accuracy. However, apparently there are no dataavailable at the higher temperatures. For this reason an investigation of thevolumetric behavior of isobutane at temperatures between 100? and 460? F. wascarried out with apparatus that has been described in another paper (p. 136, this volume).

Materials

The isobutane used in this investigation was obtained from the Philgas Divisionof the Phillips Petroleum Co. That company's special analysis upon this sampleindicated it to contain less than 0.03 mol per cent of impurities. In order toavoid traces of noncondensable gases, this hydrocarbon material was subjectedto two successive fractionations at a high reflux ratio in a columnapproximately 4 ft. long and ~ in. in diameter, which was packed with smallglass rings. The middle portion of distillate from the first fractionation wasused in the second fractionation and a portion of the overhead from this seconddistillation process was repeatedly condensed at liquid-air temperatures at apressure only slightly above the sublimation pressure of isobutane at thistemperature.

T.P. 1128
A Study of Some Phases of Chemical Control in Clay Suspensions
Authors: Garrison Allen D. , Ten Brink K.C.
Published: June 2014

A previous paper reviewed some of the properties of clays and shales andpresented some data on the nature of the gelling phenomenon. It included abrief discussion of origin of clays and shales, their composition, structure, retention of water, ionization, base exchange, and the nature of the gelling of water suspensions. Other publications of the Institute have discussed theproperties of clays and their relations to drilling-fluid behavior and control. It is the purpose of this article to present some new data obtained andarranged in a different manner and making possible a better understanding ofthe chemical reactions involved in the control of drilling-fluidcharacteristics during the normal drilling operations.

Experimental procedure

The difficulties involved in the measurements of the flow characteristics ofplastic fluids are too familiar to recite. The possible applications of some ofthe well-known instruments to this problem have been adequately discussed by Hobson and he has given an excellent bibliography. Although there are manyviscosimeters of varied design, none of them appear to fulfill the most obviousdemands of accuracy in the measurement of clay or shale suspensions. Since thefluid characteristics are dependent on the rate of flow of the fluid, and theviscosity usually falls off very rapidly as the rate is increased, it is clearthat the first requirement is that the instrument shall be capable of a widevariety of speeds. The viscosity of the fluid at any fixed and constant rate offlow is also a function of time, so that the second demand is that theinstrument shall be capable of a constant and continuous motion for a prolongedperiod of time.

T.P. 1124
Dispersion of Clays and Shales by Fluid Motion
Authors: Garrison Allen D. , Ten Brink K.C. , Elkin P.B.
Published: June 2014

It is the purpose of this article to present the results of an investigation of certain clay and shale suspensions having viscosities that are materiallyinfluenced by fluid motion, and to discuss the bearing of these results uponthe choice of policy in the control of drilling fluids. A previous articledescribed the design and the characteristics of an instrument adapted tomeasure the viscosity of plastic suspensions during continuous uniform motionand at a variety of speeds.

It has long been recognized that the viscosity of a clay suspension depends onthe past history of the fluid motion. Since an abundance of literature isavailable on this phenomenon, it is not necessary to describe it in more thangeneral terms. It is usually observed that rapid motion reduces the viscosityof a clay suspension, and that some time is required for the viscosity to fallto its equilibrium value after the steady motion is started. On reducing thespeed of motion to some lower value, the viscosity again rises, but it alsorequires some time to attain a steady viscosity value at the slower rate ofmotion. Thus clay suspensions are usually observed to be increasing inviscosity as time passes when the measurement has been immediately preceded byfluid motion that was more rapid than that employed in the measurement. And itis usually observed that the viscosity falls as time passes when themeasurement has been preceded by more quiescent conditions. Reed, and Broughtonand Hand have reported a condition of observation of clay suspensions in whichthe viscosity was observed to fall during the first few moments of steadymotion, and rise thereafter.

T.P. 1125
World Production of Petroleum Substitutes
Authors: Garfias V.R. , Whetsel R.V.
Published: June 2014

The present study is intended as a preliminary statistical survey of theworld's production of petroleum substitutes. The information presented isadmittedly deficient. It is believed, however, that the increasing importanceof these substitutes, particularly with Europe at war, justifies itspresentation at this time, if for no other reason than to encourage enlightenedpertinent discussion.

The world's production in 1939 of petroleum substitutes ? whichapproximately 97 per cent are direct substitutes for motor fuels ? istentatively estimated at 108,000,000 bbl., or equivalent to the combined outputof crude oil in 1939 of Rumania, Mexico and Colombia. With few exceptions, these figures of production represent also actual figures of consumption. TheUnited States, owing mainly to its output of natural gasoline, leads allcountries in the production of these products, with about 53 per cent of thetotal.

In European countries, particularly Germany, the imminence of war in 1939 forced an increase in production and improvement of methods of manufacturingmotor fuels, largely from coal, with the result that this country produced inthat year over 20,000,000 bbl. of substitutes. Since the beginning of.hostilities, substitutes have offered more and more the means of meeting theunfavorable balance between supply and demand in European countries; theincrease in production of these products being at least in part offset by thesystematic bombing of synthetic plants and oil storage.

T.P. 1274
New Method of Plotting Slant Holes
Authors: Atherton Tracy L.
Published: June 2014

The mapping of slant-hole oil fields is complicated by the fact thatrelationships between wells are subject to variations in three dimensions andare not readily adaptable to representation on a plane surface. Formalizedperspectives usually expand into an undecipherable maze of lines and peg modelswith the necessary supporting dividers serve only to awe the beholder withtheir perplexity. The usual compromise arrived at is a plotting of theprojection of the courses of all of the wells in the field onto a horizontalplane (Fig. I). These complicated plots, when used in conjunction with theindividual vertical projections of the wells, heretofore have been the mostpractical foundation for the study of general field problems. This method hasmany shortcomings, however, which are not found in the recently developedstraight-hole equivalent projection method. The new method supplies a series ofmaps similar to the type now in common use in straight-hole fields. It isremarkably simple to use and supplies a ready check on clearances betweenwells. Perhaps the method can best be understood if the steps that led to itsdevelopment are described.

Common practice of oil-well surveyors is to supply the owner with a tabling ofthe survey and a plan view plotted against the true meridian. If a verticalprojection is plotted, it is usually plotted separately and shows verticaldepths against the projection of the stations along a section line joining thetop and bottom of the hole on the plan view. A more practical method would beto plot the section line of the plan parallel to the abscissa of the verticalprojection (Fig. 2). If this is done, any line parallel to the "baseline" will pass through the points on each projection that represent asingle point in the hole. Another very useful graph, which the well surveyorcould provide, would be plotting of vertical depths against measureddepths.

Fig. 3 illustrates the next step facilitated by this form of plotting. Thelines designated "well A" represent the proposed course of a hole to bedrilled. Superimposed on the drawing, in its proper relative position, is theplan view and a portion of the vertical projection of a present producer,"well B." From an inspection of the plan view we arrive at the correctconclusion that the only indicated possibility of collision is at the point ofcrossing of the wells on the plan view. Referring to the vertical projection, note that the vertical depths of stations on B, in the vicinity of thecrossing, are plotted on the same plane of projection as A. The clearance isthe indicated distance between the two vertical sections measured along theparallel to the "base line," which passes through the point ofintersection of the plan view. Repeat this process for the other wells crossingthe proposed course of A on the plan view and you have a preliminary check ofclearance for the proposed course.

T.P. 1283
Validity of Competition in a Natural Resource Industry
Authors: Gill John D.
Published: June 2014

This paper assumes the incontrovertible nature of the statement that thevalidity of competition in the nonnatural resource industries is establishedfirmly on the rate and extent of the economic development of the United States.It then demonstrates the nonexistence of any condition within the petroleumindustry that would invalidate the principle of competition as applied to it.It points to the benefits that competition has effected in the oil industry andthe reasons why the practice of the competitive principle should continue tokeep the industry virile and progressive in meeting the requirements of futuregenerations for the kind of products natural to it. Finally, it pleads for aclearer view of the affairs of the oil industry by seeing them against abackground of the whole economy.

Introduction

Even a few years ago there would have been only an academic reason forpresenting before this Institute a paper on the validity of competition in theoil industry or any other natural resource industry; today there is no morepractical subject for this body to consider. In social importance it transcendsattempted solutions of perplexing technical problems; and even the numerouslegal and economic problems that grow out of administration of state regulatorymeasures appear to be of secondary importance because they would cease to existif competition were abolished.

The aspiration of certain elements of the Federal Government to acquirecontrol of the oil industry has long been suspected and so frequently indicatedas to need no documentation here. The President's attitude, as expressed in thefollowing statement from an open letter to Representative Cole, is noteworthybecause of its high authority:

The vital need for petroleum in the national defense ?confirms my belief inthe urgent need of Federal legislation to safeguard our petroleum supplythrough prevention of waste and by establishment and maintenance of soundeconomic conditions in-the oil industry?

But also it may be dismissed with this mere mention of it because itpredicates government control and the abandonment or broad reduction ofcompetition on a war emergency. Clearly, the fight for a nation's life mayjustify a government's control over men and resources that would be abhorrentand economically enervating under conditions of national security.

T.P. 1324
Production under Effective Water Drive as a Standard for Conservation Practice
Authors: DeGolyer E.
Published: June 2014

The problem of good engineering practice and of good conservation practicein oil production is that of keeping gas in solution. This can best be done byproducing a field as a water-drive field. Some degree of water drive isbelieved to be present in most fields but in the past most fields have beenproduced too rapidly to allow water drive to be effective. Ultimate recoveryshould be 50 per cent greater for fields produced by water drive over that fromgas-expansion fields. Wide spacing will permit fields of low-degree water driveto be produced effectively as water-drive fields.

Introduction

Neglecting all the complicated scientific and technical argument that leadsto the conclusion, the solution of the problem of good production practice, ofgood engineering practice, and of good conservation practice in oil productionis to keep gas in solution. This can best be done by producing fields at a ratelow enough to make effective the water drive, which exists, it is generallybelieved, to a degree great enough to be made effective in more than 80 percent of the fields of the United States. Oil is being so produced in the TenSection field of California; the Hobbs field of New Mexico; the Yates, Hastings, Friendswood, Anahuac fields and the main sand of the Conroe pool, inTexas; the Magnolia pool in Arkansas, and doubtless in many other pools.

The measures of success in the efforts to achieve the solution of theproblem are the maintenance of bottom-hole pressure and the prevention of anincrease in gas-oil ratio. Some decline from the original bottom-hole pressureand the production of some gas are essential. A pressure gradient from thereservoir to the well is necessary and at least as much gas must be produced asthat in solution in a barrel of oil. Once the optimum pressure and the gas-oilratio have been established, they should be maintained.

T.P. 1340
Effect of Gravel on Unconsolidated Sands
Authors: Gumpertz Ben
Published: June 2014

The important factors in any study of the screening of sand with a gravelenvelope, as applied to use in oil wells, are:gravel size upon sand migrationsand size and shapegravel size and shaperatio of gravel size tosand sizeflow velocityviscosity of the fluid.

Perhaps the first extensive investigation of the function of gravel inscreening sand was performed by Coberly and Wagner,' from which the followingconclusion was drawn: "The diameter of the largest grains in a singleclassified sand suitable for gravel packing is approximately 13 times the grainsize at the ten-percentile analysis of the formation sample." This appliesto sands classified by Tyler screens and is for gravel grains of the maximumsize that could be used to form a stable bridge. Field practice has shown thatthe screening effect of a given gravel for a given sand apparently varies withthe flow velocity. 2 Also, it has been assumed by some operators that thethickness of the walls of the gravel envelope surrounding the well has littleeffect upon the screening process. It is thought by others that a narrowenvelope of gravel might form an ineffective screen. Thus the purposes of thiswork are:To investigate the effect of gravel-sand size ratio upon screening actionunder the condition of varying flow velocities.To investigate the effect upon screening action of varying the thickness ofthe gravel screen.To investigate sand migration in the gravel screen and the effect of flowvelocity and gravel size upon sand migration.

Description of Apparatus

In an attempt to reproduce field conditions for the purposes of thisinvestigation, a flow tube was constructed, according to the manner of Uren, torepresent a radial drainage segment of an oil sand.

To arrive at the dimensions of the flow tube, a radial drainage segment ofrectangular cross section was assumed to define an area of 2 sq. in. on theface of a well 6 in. in diameter. From this the dimensions of the segment werecalculated out to a distance of 5 ft. from the face of the well. By computingcross-sectional areas at a number of sections along the rectangular segment andtransforming these areas into the circular form, a drainage cone was obtainedhaving everywhere the same cross-sectional area as the drainage element ofrectangular cross section.

To construct the apparatus, two sections of pipe of 7 5/8 in. inside diameter, one 13 in. and the other 4 ft. long, were joined by a bolted flange. A mandrelhaving the dimensions of the drainage cone was centered in the pipe and a neatcement mixture was cast around it. A protective gasket was placed between thetwo sections of pipe so that the cement body could be separated at that point.When the mandrel was withdrawn a drainage cone was obtained

A round slotted screen, which could be screwed up against the end of thedrainage cone, held the gravel in place.

T.P. 1195
Measurements of the Viscosities of Oils under Reservoir Conditions
Authors: Hocott C.R. , Buckley Stuart E.
Published: June 2014

The viscosity of the oil in the reservoir is one of the properties thatinfluence its movement through the sand to producing wells. Measurements ofviscosity, therefore, are pertinent to problems associated with well behaviorand with the estimation of recoveries, and afford an indirect means for partialevaluation of various methods of controlling reservoir behavior. The effect ofdissolved gases on the viscosity of crude oil has been determined, but no datahave been published on the viscosity of representative samples of reservoiroils, This paper describes a simple instrument that has been used to determinethe viscosities of a number of subsurface oil samples at the temperatures andpressures existing in the reservoirs, and presents the results of thedeterminations for typical fields.

Construction of the Apparatus

The principal requirements of any instrument used for the examination ofsubsurface samples are that it be strong and simple both in design and inmethod of operation. Accuracy beyond that of the degree of reproducibility ofsubsurface samples from various wells in a reservoir or exceeding that of thecommon measurements of reservoir temperatures and pressures is not required.Because of the expense of procuring subsurface samples, it is necessary alsothat the instrument operate on a relatively small fraction of a sample, leavingthe remainder for other tests, and that there be few or no failures of the equipment to cause undue delay orloss of a sample.

After preliminary experiments with a falling bullet, the results of which werenot satisfactory, a simple viscosimeter was built of the rolling ball typefirst proposed by Flowers and later used by several investigators. Theapparatus consists essentially of a removable, accurately bored cylindricalbarrel of 1/4-in. nominal internal diameter, 8 in. long, in which a closely fitting steel ball rolls through the oil with thebarrel inclined at a definite angle, The ball makes contact at one end of thebarrel with an insulated electrode, closing an electrical circuit, whichactuates a buzzer. The measurements consist essentially in determining the timerequired for the ball to travel the length of the barrel.

The details of the construction are shown in Fig. 1. The barrel in which theball rolls was made from a section of 2s-caliber blank rifle barrel, speciallybored to an exact uniform diameter and polished. The barrel slides snugly intoa hole bored in a solid stainless-steel cylinder, an upper external shoulder ofthe barrel compressing a small spring, and is held in place by a hollow nut.The spring prevents the barrel from seating against the bottom of the boredhole in the cylinder, while narrow external longitudinal slots in the barrelpermit fluid to flow around it and through the bottom.

T.P. 1220
Pressure Distribution about a Slotted Liner in a Producing Oil Well
Authors: Miller Frank G.
Published: June 2014

The lower cost of producing oil from naturally flowing wells compared withproduction costs accruing from artificial lifting methods has stimulated muchresearch, with the joint purpose of extending the natural flowing life of wellsand of increasing the productivity of small wells. The laboratory investigationdescribed herein was made to determine the effect of a slotted liner on thepressure gradient in the vicinity of the wall of a flowing well. Flowrestrictions caused by the liner induce energy losses between the oil-bearingformation and the inside of the liner, which may be reduced by improved linerdesign, and thereby the flow capacity of wells may be increased. These losseshave been evaluated for rectangular slots of different sizes, and means aresuggested for reducing them.

The dearth of information concerning the nature of the flow of fluids fromunconsolidated sands through small openings in the walls of pipes-asrepresented by the flow of oil from an oil sand into a slotted liner-isacknowledged. Although the benefits to be realized by operators through the useof optimum liners is just beginning to be recognized generally, Coberly in 1937pointed out that the functioning of screen casing is an important factor in theproduction of oil. From his study on the selection of size of oil strings forwells in California, Parks concluded, in part, that the perforated section ofthe oil string deserves continued study, especially with respect to theselection of perforations.

The growing use of gravel packing resulting from certain research findingslends even more significance to the problem of selecting optimum liners, as theapplication of these methods usually requires slotted liners or other kinds ofperforated liners.

The present study was made to, obtain further information for the guidance ofengineers and operators in selecting slotted liners and to develop a laboratorymethod that may be used in analyzing possible pressure conditions surroundingmost types of perforated casings used in producing oil wells, so that thepresent inadequate fund of knowledge on this important subject may beexpanded.

Discussion of Problem

At the beginning of the investigation the following assumptions were maderegarding bottom-hole conditions of a producing oil well and the oil-sandreservoir it penetrates:Conditions of steady-state flow existasingle-phase homogeneous liquid is being producedno contaminatingmaterial (such as drilling fluid) is present between the liner and the face ofthe oilbearing sandthe well is vertical and completely penetrates ahorizontal sand stratum of uniform thickness occurring between two impermeablestratathe flow is wholly viscous.

T.P. 1222
Volumetric Behavior of Oil and Gas from the Rio Bravo Field
Authors: Sage B.H. , Reamer H.H.
Published: June 2014

Attempts have been made to predict the volumetric and phase behavior ofnaturally occurring hydrocarbon mixtures but these methods have not beenextended to the higher pressures and temperatures that are currentlyencountered in some producing formations. Furthermore, the methods ofprediction at present available have not been tested in a sufficient number ofcases to ensure their applicability to all naturally occurring hydrocarbonmixtures, even at the lower pressures and temperatures. For these reasons thebehavior of a number of hydrocarbon mixtures from a field in which thesubsurface pressures are above 4500 lb. per sq. in. and the temperatures are inthe neighborhood of 250F was investigated.

Methods

The objective of this program was to determine the volumetric behavior ofmaterial as it existed in the reservoir as a function of pressure, temperatureand composition. Strictly speaking, this cannot be accomplished in any simplefashion. However, the variations in composition that are encountered within aproducing reservoir my be approximated roughly by means of mixturers made up oftwo arbitrarily chosen constituents. Experience indicates that the liquid andgas phases from a high-pressure gas trap afford a simple source of material forthis purpose. Throughout this discussion the samples of the gas phase andliquid phase from the production trap will be called the "trap-gassample" and the "trap-liquid sample" respectively.

The volumetric behavior of both of the trap samples wasdetermined throughout the temperature interval between 100F and 250F atpressures up to 5000 lb. per sq. in. In addition, the behavior of eightdifferent mixtures containing varying proportions of the two trap samples wasstudied throughout the same temperature and pressure intervals. Theexperimental results yielded information concerning the specific volume of thematerial as a function of pressure, temperature and the relative quantity ofthe trap samples.

The relative amount of each of the paraffinhydrocarbons of lower molecular weight than n-hexane was determined for each ofthe trap samples. In addition, the specific weight, viscosityandaverage molecular weight of the hexanes-and-heavier fraction of thetrap samples and eight systematically chosen mixtures.

Materials

The gas and liquid samples were obtained from the production trap of a well inthe Rio Bravo field in California durring the fall of 1939.

T.P. 1251
Productivity Index and Measurable Reservoir Characteristics
Authors: Lewis James A. , Horner William L. , Stekoll Marion
Published: June 2014

The data in this paper show a relationship between measured productivityindex and certain commonly measured reservoir characteristics. Comparison ismade of theoretical radial flow assuming certain drainage radii and thetentative relationship shown by these data. Among the more importantmeasurements found to correlate with productivity index are permeability, formation thickness, oil viscosity at reservoir conditions, andformation-volume factor.

Introduction

The need for reliable means of predicting rates of fluid flow into wells hasbeen recognized for a number of years. As early as 1898, physical measurementsof the sand to determine productivity were described by Slichter and King as anaid in the determination of water supply. The United States Geological Surveyhas made frequent use of permeability measurements on samples of water sand toaid in predicting the rates of flow from wells, and practical applications ofpermeability data to problems of water-flooding have been made since 1932.

It is now becoming widely recognized that the economics of well spacing andfield operations may be solved only after evaluation of several factorsinfluencing subsurface flow. A number of papers published during the past fewyears indicate the possibility of determining the productivity index of oilwells from permeability and other factors, but these contributions have dealtprimarily with the theoretical relationships involved and were not intended tofurnish results that could be used to determine a working equation forpredicting well performance from laboratory tests.

In this paper, reliable determinations of productivity index are given for anumber of wells, together with some significant results from core analyses andbottom-hole sample analyses.

T.P. 1467
The Electrical Resistivity Log as an Aid in Determining Some Reservoir Characteristics
Authors: Archie G.E.
Published: June 2014

The usefulness of the electrical resistivity log in determining reservoircharacteristics is governed largely by:the accuracy with which the trueresistivity of the formation can be determined;the scope of detailed dataconcerning the relation of resistivity measurements to formationcharacteristics;the available information concerning the conductivity ofconnate or formation waters;the extent of geologic knowledge regardingprobable changes in facies within given horizons, both vertically andlaterally, particularly in relation to the resultant effect on the electricalproperties of the reservoir.

Simple examples are given in the following pagesto illustrate the use of resistivity logs in the solution of some problemsdealing with oil and gas reservoirs. From the available information, it isapparent that much care must be exercised in applying to more complicated casesthe methods suggested. It should be remembered that the equations given are notprecise and represent only approximate relationships. It is believed, however, that under favorable conditions their application falls within useful limits ofaccuracy.

Introduction

The electrical log has been used extensively in a qualitative way tocorrelate formations penetrated by the drill in the exploitation of oil and gasreservoirs and to provide some indication of reservoir content. However, itsuse in a quantitative way has been limited because of various factors that tendto obscure the significance of the electrical readings obtained. Some of thesefactors are the borehole size, the resistivity of the mud in the borehole, theeffect of invasion of the mud filtrate into the formation, the relation of therecorded thickness of beds to electrode spacing, the heterogeneity of geologicformations, the salinity or conductivity of connate water, and, perhaps ofgreatest importance, the lack of data indicating the relationship of theresistivity of a formation in situ to its character and fluid content.

On the Gulf Coast it is found that the effects of the size of the boreholeand the mud resistivity are generally of little importance, except when dealingwith high formational resistivities or extremely low mud resistivities.Fortunately, little practical significance need be attached to the exact valuesof the higher resistivities recorded. Low mud resistivities are not common, butwhen this condition is encountered it may be corrected by replacing the mudcolumn. With the present advanced knowledge of mud control, invasion of mudfiltrate into sands can be minimized, thereby increasing the dependability ofthe electrical log. The effect of electrode spacing on the recorded thicknessof a bed is often subject to compensation or can be sufficiently accounted forto provide an acceptable approximation of the true resistivity of theformation.

T.P. 1422
Field Application of Core Analysis and Depth-pressure Methods to the Determination of Mean Effective Sand Permeability
Authors: Van Wingen N.
Published: June 2014

Effective sand permeabilities can be ascertained from core analysis if thelaboratory data are compensated to allow for the presence of connate orresidual water. Such adjustments can be made by applying empirically derivedcorrection factors.

Effective sand permeabilities can be estimated also from analytical studiesof field depth-pressure measurements. In one method the time rate of pressurebuild-up after a well is shut in from steady-state flow is required, and in theother the direct measurement of a steady-state rate of flow and thecorresponding equilibrium pressure.

The results of the investigation discussed in this paper demonstrate thatthese methods for determining mean effective sand permeabilities can becorrelated.

Introduction

In recent years many investigators have demonstrated the practical value ofan accurate knowledge of the physical and dynamical characteristics ofreservoir sands containing oil and gas. Of these factors, which serve tocompletely define a porous medium as a container or carrier of fluids, thedynamical characteristics are of particular interest to the production engineerbecause they afford a direct measure of the rate at which the oil or gascontent of a reservoir will become available. The constant that definesdynamically the porous medium as the carrier of a homogeneous fluid in viscousmotion is the "permeability."

Core-Analysis Method

The generally accepted practice in compiling permeability data has been toanalyze in the laboratory core samples taken in the course of drilling throughthe productive horizon, and to obtain the mean measure of the productiveability or permeability for the interval open to production by graphicalintegration of the permeability profile.

An average permeability ascertained in this manner, however, is useful tothe production engineer only for comparisons of wells drilled in the samehorizon, as permeabilities determined in the laboratory are measures of onlythe ability of a porous medium to transmit a single fluid. As a result of manyinvestigations, it has been shown, however, that under actual reservoirconditions water is coexistent with the petroleum and that its presence greatlyreduces the permeability of the sand to oil.

T.P. 1464