bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Temperature and Pressure on Rheological Properties of Cement Slurries
Authors: Farris R. Floyd
Published: June 2014

A thorough knowledge of the behavior of cement slurries under elevatedtemperatures and pressures is necessary in order to solve properly the manyproblems presented in deep-well cementing operations. In the earlier days ofthe petroleum industry the depths of wells were shallow as compared to those oftoday, and the subsurface temperatures and pressures were not of sufficientmagnitude to affect seriously the problem of proper control of cement-slurryproperties. Today, however, the search for new reserves has extended drillingto such depths that bottom-hole temperatures of more than 200?F. andbottom-hole pressures of 3000 to 5000 lb. are not uncommon. Moreover, there isevery indication that within the next few years wells will be drilled to evengreater depths and bottom-hole temperatures and pressures will becorrespondingly higher than those with which we are concerned today.

It has been realized for some time that the behavior of cement slurries at hightemperatures and pressures might be very different from that at atmospherictemperature-pressure conditions, but while the temperature effects have beeninvestigated with a reasonable degree of thoroughness, the pressure effectshave received little public attention.

While the trend toward deeper drilling may make changes in cementing techniqueand the choice of cements imperative, it was the purpose of this investigationto consider factors having a bearing on the latter, only secondaryconsideration being given, for the present, to details of technique andequipment for oil-field use. More specifically, the purpose of this work was toconsider the effect of temperature and pressure upon the behavior of cementslurries.

Although it has long been recognized that cements thicken and set rapidly withincreasing temperatures, practical methods for the quantitative determinationof these effects are comparatively recent developments. In 1935 Silcox and Rulepresented such a method, describing apparatus designed to measure theconsistency-time relationship of cement slurries at relatively hightemperatures. The practical importance of this apparatus in furnishing usefuldata for the evaluation of cement slurries for cementing operations has beenemphasized in various technical publications by such writers as E. L. Davis, F.Bingham, and J. E. Weiler. A paper describing the numerous tests now used toevaluate cements for oil wells was presented in 1939 by W. W. Robinson."Robinson describes the Consistometer and the ThickeningTime Tester, showingsimilarity of data from the two devices, and points out that the purpose ofeach apparatus is to determine the allowable time that a cement may be pumpedat a given temperature.

T.P. 1207
Phase Behavior in the Methane-propane-n-pentane System
Authors: Carter R.T. , Sage B.H. , Lacey W.N.
Published: June 2014

The phase behavior of a number of binary systems consisting of paraffinhydrocarbons has been determined in recent years. In addition, the compositionof the coexisting phases of mixtures of crude oil and natural gas has beeninvestigated. However, the latter study did not include information concerningthe influence of the concentration of a component upon its distribution betweentwo coexisting phases. Owing to the paucity of such information it wasconsidered desirable to investigate in some detail the composition of thecoexisting phases in the methane-propane-n-pentane system throughout thegreater part of the two-phase region at a temperature of 100?F. Information ofthis nature also permits the establishment of the critical behavior of thisternary system.

Method

The compositions of the coexisting phases in this ternary system at 100?F weredetermined by withdrawing samples from a pressure vessel containing aheterogeneous mixture of the three components that had been brought toequilibrium by mechanical agitation at the desired pressure and temperature.The samples were withdrawn under such conditions that the equilibrium was notdisturbed and the composition of each of the phases was ascertained by means ofthe conventional low-temperature fractionation procedure.

The apparatus employed in this investigation was nearly the same as thatutilized in an earlier study of the methane-n-pentane system. Several minormodifications in the arrangement of the apparatus were made in the interest ofsimplifying the procedure and avoiding the possibility of condensation in thetubing connecting the equilibrium apparatus with the analytical equipment. Thepressures were measured by means of a pressure balance with a precision of 0.5lb. per sq. in. It is believed that the equilibrium pressure was ascertainedwith an uncertainty of not more than 2 lb. per sq. in., even though smallvariations in pressure obtained during the withdrawal of the samples. Thetemperature of the equilibrium equipment was maintained by use of anautomatically controlled oil bath. The bath temperature was determined by meansof a copperconstantan thermocouple, the electromotive force being determined bymeans of a potentiometric circuit of such a nature as to reduce the uncertaintyof the temperature to less than 0.1?F.

The fractionating column employed in the determination of the composition ofthe gas phase had a diameter of 0.12 in. and was approximately 4 ft. long, while the column employed in the analysis of the liquid phase was 0.18 in. indiameter and about 5 ft. long. Each column was equipped with the conventionalconstant-volume receivers, which were maintained at a constant temperature bymeans of an automatically controlled oil bath.

T.P. 1250
Fineness and Water-cement Ratio in Relation to Volume and Permeability of Cement
Authors: Coleman J.R. , Corrigan G.L.
Published: June 2014

Four factors that largely determine the end product obtained when cement andwater are mixed are the chemical composition of the cement, the fineness towhich the cement is ground, the amount of mixing water used, and the procedureused in mixing the slurry. In order to study the effect of two of thesefactors, the other two, the chemical composition and method of mixing, are keptconstant, leaving as variables fineness and water-cement ratio.

Through years of experimentation and usage it has been well established thatthe reduction of cement clinker to a very fine state by grinding improve itscementing value, principally because the reaction between cement and watertakes place only at the surface of the cement particle, further action beinghindered by the accumulation of reaction products that tend to coat theunreacted material. Therefore, the more finely ground a cement, and the greaterthe surface exposed in proportion to its mass, the more rapid is the hydrationrate. Similarly, the greater the surface exposed, the greater the proportion ofthe cement that reacts, and the lower the amount of residue that is unreactedand so remains inert and unable to make any contribution to cementingproperties.

Although it is more expensive to manufacture a finely ground cement than acoarser cement, the advantages of fine grinding of construction cements were somarked that the fineness of cement has increased considerably in past years.When the manufacture of special oil-well cements was begun, it was necessary toconsider properties of cement that previously were considered of minorimportance, foremost of these being pumpability. Since, with the water-cementratio constant, a finely ground cement will produce a neat slurry of higherconsistency and shorter time of pumpability than will a coarser cement, thereis a tendency to grind oil-well cements to a lower degree of fineness.Therefore, in order to produce oil-well cements that will make a slurry havinga long time of pumpability, cements are manufactured that because of theircoarseness generally are poorer cementing materials than some of the morefinely ground construction cements. On the other hand, often it is necessary topump oil-well cements for long periods of time to place them properly behind astring of casing in a deep well, and since high strength is not of foremostimportance for such cement, there is room for considerable controversyconcerning the proper fineness range.

T.P. 1266
Some Theoretical Considerations on the Problem of Well Shooting
Authors: Evinger H.H. , Muskat M.
Published: June 2014

Although the shooting of oil wells for the purpose of increasing productionhas been practiced since 1866, present-day shooting technique has been arrivedat almost wholly by a process of trial and error. The difficulties attendingeither a theoretical analysis of the problem or an experimental attack becomeapparent when one actually embarks on a theoretical investigation or attemptsto formulate an intelligent experimental program. The literature on the subjectconsists mainly of descriptions of current practice, scattered eye-witnessaccounts of events following the shooting of a well, and vague speculations onthe mechanical processes involved.

In contrast to quarry blasting, the results of oil-well shooting cannot bedetermined by means of visual inspection, and it is perhaps for this reasonthat only one attempt at what approaches a direct experimental attack has beenreported in the literature. In these experiments, charges of liquidnitroglycerin were exploded in holes drilled in a sandstone outcrop. In orderto observe the character and extent of the resulting fractures, the rock wasblasted away so as to expose the original shot holes. After all this had beendone it was found impossible to distinguish the fracturing due to the originalshots from that due to the subsequent blasting. The enlargement of the holesdue to the pulverizing action of the shots was measured and an attempt was madeto determine the effectiveness of sand tamping. Only five shots were made andfew definite conclusions could be drawn.

Some small-scale experiments to determine the effect of tamping were performedby Snelling and Hall. Small charges (20 grams) of dynamite were detonated atthe bottom of a cylindrical hole in a lead block and the resulting enlargementof the hole was taken as a measure of the effectiveness of the explosion. Itwas found that when the shot was tamped with a sufficient amount of sand orclay, the volume enlargement was approximately double that found when nostemming had been used.

The properties of the explosives have been the subject of much study by themanufacturers, the U. S. Bureau of Mines, and various other agencies, Forexample, velocities of detonation for many commercial explosives are to befound in the Blasters' Handbook, issued by the Du Pont company. Many otherproperties are given in a treatise on the subject by Naoum. The shock wave thataccompanies the detonation of high explosives has been studied photographicallyby Payman and others. The hydro dynamical theory of the shock wave has receivedmuch attention, and an extended theoretical treatment is given byBateman.

Two aspects of the well-shooting problem will be considered in this paper;namely, the fracturing of subsurface strata, and possible damage to casing.With respect to the former of these, several calculations have been made givingthe stresses in the rocks surrounding the shot.

T.P. 1268
Effects of Pressure and Temperature on Condensation of Distillate from Natural Gas
Authors: Buckley Stuart E. , Lightfoot J.H.
Published: June 2014

Deep drilling has led to the development of numerous pools which yieldproducts consisting predominantly of natural gas accompanied by high-gravitywater-white or slightly straw-colored liquid. Yields of this"condensate" or "distillate," as it is commonly called, vary fromtraces to over a hundred barrels per million cubic feet of gas. The fact thatthis liquid exists in the reservoir as an integral part of the gas phase and isformed by condensation attending simultaneous reduction of pressure andtemperature after its entry into the well was apparently first recognized about1932.1 The nature of the physical phenomena involved in this condensation wasclarified for the petroleum industry in 1933 by a report by Sage, Schaafsma, and Lacey of the results of an experimental investigation of the behavior ofmixtures of methane and propane.

Search of the literature has revealed that the condensation of liquid fromgaseous mixtures by isothermal pressure reduction is not a new discovery.Kuenen was led by theoretical considerations to expect such a phenomenon, andin 1892 reported the results of experimental verification of his deductions.This was followed by a considerable amount of work on the phase relations ofmixtures by Kuenen and by others, mostly in European universities. Since 1930investigators in this country have reported experimental data on the properties and behavior of a number of hydrocarbon systems.

It is now generally known that in the presence of natural gas the solubility inthe gas phase of the heavier and normally liquid hydrocarbons increasesrapidly with increasing pressure above 500 to 1000 lb. per sq. in. Thus, at pressuresof 2500 lb. per sq. in. or higher a gas may contain appreciable quantities ofhydrocarbons with normal boiling points as high as 600?F., which in turn may becondensed from the gas phase by the reduction of their solubility thereinattending pressure reduction. The combined effects of pressure and temperatureon condensation and vaporization of mixtures are most readily visualized by thestudy of phase diagrams. Since the construction, application, andinterpretation of such diagrams have been described fully in readily availableliterature, this paper will not review the theoretical aspects of thissubject.

While the behavior of gas-distillate systems is now clearly understood, atleast in a qualitative way, most of the published work deals with the resultsof laboratory studies of binary systems or of synthetic mixtures ofhydrocarbons, and although several systematic investigations of the effects ofseparator pressure and temperature on the yields of liquid product fromgas-distillate wells have been made it appears that in all cases thelimitations have precluded the construction of even approximately completephase diagrams for naturally occurring systems.

T.P. 1269
Sampling Gas-condensate Wells
Authors: Flaitz J.M. , Parks A.S.
Published: June 2014

Of the various methods of sampling gas-condensate wells, a method thatsecures a continuous representative sample of the well stream is desirable.Such a method, consisting of a sampling tube introduced into the well tubing, has proved satisfactory. The method is sufficiently accurate for operating andengineering problems. A portable testing apparatus can be used with thesampling tube to obtain data useful in studying the economic and technicalaspects of the development and operation of gas-condensate properties.

Introduction

The recent discovery and development of gas reserves that containhydrocarbons that condense with reduction of temperature or pressure, or both, to form a product known as condensate, has brought many new problems to the oiland gas industries. With further discovery of deep, high-pressure fields it ispresumable that many more gas fields of this type will be added to the steadilyincreasing number. Such gas reserves are found either associated with oil as agas cap or in separate formations. There seems to be no positive correlationbetween the physical or geological nature of the reservoir, and the chemicalcomposition or phase characteristics of its contents.

Knowledge of the chemical make-up and phase behavior of gas-condensatereserves is needed to cope with many problems. A knowledge of the chemicalcomposition and phase characteristics of the reservoir material is necessary toproperly design a gasoline or recycling plant, to estimate natural gas andcondensate reserves, to enable the operator to study the economic and technicalaspects of various methods of operation and development, and to carry out theplan of operating subsurface and surface lease equipment. This information isoften useful in questions of mineral ownership, proration, legal position, andtaxation.

It is the purpose of this paper to discuss methods used by the writers todetermine the chemical composition and phase characteristics of the fluidsproduced from a condensate well. The scope of the paper includes a discussionand description of the method of sampling, the results of tests on the accuracyof the sampling method, a description of a portable testing apparatus used toexamine the phase characteristics, typical results of tests on wells fromseveral condensate fields, and some of the applications of these data toproduction problems.

References to previous work on this subject are cited at the end of thepaper.

T.P. 1374
Engineering Economics of Long Petroleum Pipe Lines
Authors: Hill Edgar G.
Published: June 2014

Much has been written and said recently about the methods used and materialsand equipment employed in building the long tubes that criss-cross a great partof the United States, like the pattern of a spider's web. This paper willdiscuss the fundamentals of design of these lines from the economic as well asthe engineering viewpoint, pointing out the effect of the volumes transported, and the load factor at which they are operated, on the unit costs oftransportation, as well as the effects on costs of the character of the fluidsthe lines are called upon to handle.

Generally speaking, crude-oil pipe lines carry oil from the producing fieldsto the refineries. Sometimes part of the journey is by pipe line to a coastalpoint and tank ships are employed for the rest of the trip.

The main lines of directional flow of crude oil through pipe lines in theUnited States are shown on Fig. I, but this, of course, does not always showindividual pipe lines.

T.P. 1433
Possibilities of Secondary Recovery for the Oklahoma City Wilcox Sand
Authors: Katz Donald L.
Published: June 2014

The Oklahoma City Wilcox sand, discovered on March 26, 1930, has produced394 million barrels of crude oil and 819 billion cubic feet of natural gas asof July 1, 1941. The 100,000 bbl. wells, pressures of 2600 lb. per sq. in., andflows of "Wilcox" sand caused exciting moments in the early life of thefield. Today the reservoir is substantially at atmospheric pressure andproduces 75,000 bbl. of crude oil daily through 466 pumping wells. Earlyestimates of the initial crude-oil content of the "Wilcox" sandindicated that about 600 million barrels of crude oil would remain after thepumping wells ceased to produce economically. The Oklahoma City WilcoxSecondary Recovery Association was organized in March 1939, to study thepossibilities of recovering a portion of this oil.

Only a very brief summary of the information available can be presented in apaper of this nature. Some simplifications and generalizations are necessary togive the over-all picture in so short a space and statements made may not applyto a specific well or small area. Since the area under consideration by theAssociation is that north of the south line of section 22–11–3, someinformation will be presented for areas A, B, C, 1, 2, 3 and part of 4 of Fig.2, and some will be for the entire Wilcox zone west of the fault.

This paper is essentially an abstract of an engineering report made by A. D.Small, B. T. Murphree, M. C. Sons and the author for the Oklahoma City WilcoxSecondary Recovery Association on Sept. 5, 1940. Some information is taken froma report to the Association by C. V. Sidwell on March 1, 1940, and some dataare from a recent report by A. D. Small. It gives a brief history of the Wilcoxzone, estimates of the initial oil contents of the reservoir, presentconditions in the reservoir, and probable results from several programs of"secondary recovery."

History of Wilcox Zone

The Wilcox sand lies on the flank of the general structure, as shown bycross section of Fig. 1 and areal map of Fig. 2. The sand is of Ordovician ageand is composed of well-assorted, rounded sand grains with no apparentcementing material. The loose texture of the sand is shown by the enormousquantities of sand production from the wells and from the soft cores. Theproductive sand varies from zero thickness on the east to 220 ft. maximum andto zero thickness on the west because of water.

T.P. 1400
Core Analysis - an Aid to Increasing the Recovery of Oil
Authors: Lewis James A.
Published: June 2014

It is the purpose of this paper to show the importance of sandcharacteristics, when combined with other physical data, in evaluatingproduction obtained by secondary recovery operations, and to indicate thebenefits to be gained from the application of these principles to primaryproduction.

Introduction

During the past 10 years there has been a growing interest within theindustry regarding the movement of fluids through oil reservoirs. A number ofresearch projects have been directed toward the development of the physicallaws governing this movement. In the period 1933 to the present, correlationsbetween laboratory analysis of cores, reservoir fluids and well performancehave been established and have been applied to successful secondarywater-flooding recovery operations; and to the completion, production, reconditioning and evaluation of wells in new fields.

The application of these data to waterflooding, either natural orartificial, is comparatively new, but the principles involved were set forth in1880 by John F. Carll, who said:

"The flooding of an oil district is generally viewed as a greatcalamity, yet it may be questioned whether a larger amount of oil cannot bedrawn from the rocks in that way than by any other, for it is certain that allthe oil cannot be drawn from the reservoir without admission of something totake its place.

If one company owned all of the wells drawing upon a pool, and had accuraterecords of the depth and characteristics of the oil producing stratum in eachwell, it is quite possible that some system might be devised by which watercould be let down through certain shafts, and thus the rocks be completelyvoided of oil and left full of water. As it is, however, no systematized planof action can be adopted. The careless handling of one well, by which water islet down to the oil rock, may spoil several others belonging to differentparties. A clashing of interests at once arises and is likely to result indisaster to the whole district…"

T.P. 1487
Petroleum-refining Methods Available for Wartime Demands
Authors: Thornton J.F. , Dickerman W.C.
Published: June 2014

Total global war is making extraordinary demands on the oil industry. Hugequantities of 100-octane gasoline, extreme service lubes, toluene and othermiscellaneous products are required. 100-octane gasoline is blended fromisopentane, base stock, and alkylate. Isopentane is fractionated from naturalor refinery gasoline; but since only limited quantities of base stock can bemade in this way, catalytic cracking is rapidly becoming the major source ofbase stock. Alkylate, the most important component, is synthesized fromisobutane and an olefin. Extraordinary demands are forcing the full utilizationof all present sources and the development of new supplies of feed stocks.Fortunately, the United States finds itself with well-developed processesalready available, and this is true of the manufacture of lubricating oil aswell. Toluene is now being produced by new methods from special cutsfractionated from selected crudes or from catalytically processed naphthas.Designers of refinery equipment are modifying past practices to conserve everybit of material possible.

The present world war is making severe demands upon the American petroleumindustry. Not only are large quantities of high-quality fuels and lubricantsrequired but, in addition, the petroleum industry must supply strategiccommodities such as toluene for the manufacture of explosives and stocks forproducing synthetic rubber. The production of these vital raw materials, whichin reality are chemicals, is made possible by years of costly research anddevelopment by the petroleum industry. The vision of its leaders has resultedin the development of a petroleum technology that has expanded the oil businessinto a most highly developed type of chemical industry. This is one of thegreatest assets of our nation in meeting wartime demands.

In considering a program of expansion for the manufacture of additionalvital products, the refiner is faced with an amazing variety of processingmethods. Some of the processes involved are well known and are described in theliterature, while others are just reaching the commercial stage and detailshave not been publicly disclosed. This paper will outline certain processingroutes and discuss the general background involved in the selection of refiningmethods. Needless to say, the nature of the subject will not permit detaileddiscussions of refining methods, but certain generalized ideas will bepresented with regard to the related engineering viewed in light of the presentemergency.

T.P. 1503
Control of Filtration Characteristics of Salt-water Muds
Authors: Gray G.R. , Foster J.L. , Chapman T.S.
Published: June 2014

The wall-building properties of salt-water drilling muds can be improvedmarkedly by the addition of:natural gums, such as tragacanth, karaya, andghattiseaweeds, such as Irish mossgelatinized starch.

Results oflaboratory tests have been confirmed by field trials. For drilling operationsin which the mud becomes contaminated by salt, either through penetratingsalt-bearing rocks or by addition of sea water to the mud, the added costresulting from the use of one of the substances listed above is more thanoffset by freedom from stuck drill pipe and ease in running casing.

Introduction

It has been recognized for many years that oil production might be seriouslyhampered by infiltration of water from the drilling mud. As knowledge of themechanism of the wall-building process advanced, methods were developed forevaluating the filtration characteristics of muds.

The wall-building properties of freshwater muds are commonly regulated bythe addition of bentonitic clays, or of agents to promote the dispersion of thenatural mud solids. When strata bearing soluble salts are encountered in thecourse of drilling, the salts are incorporated in the mud; the clay solids areflocculated and water loss is increased tremendously. Methods generally used incontrolling filtration of freshwater muds are no longer applicable.

The problem of reducing water loss from salt-water muds is not confined toany particular area, but is acute in parts of West Texas. Salt beds severalhundred feet thick must be penetrated before the oil-bearing formation isreached. Since the formation drilled does not provide mudmaking material, it isnecessary to use large quantities of commercial clays, and even the bestcommercial clay does not afford relief from the problem of high filtration.

A laboratory study has been made of methods of improving the filtrationcharacteristics of salt-water muds, and some of the methods have been used infield practice.

T.P. 1351
Natural Gas Hydrates
Authors: Carson Don B. , Katz Donald L.
Published: June 2014

Natural gases under pressure form crystalline hydrates with water.Experimental data are reported on four-phase equilibrium for themethane-propane-water, methane-pentane-water, and methane-hexane-water systems.Temperatures and pressures for equilibrium between gas, water-rich liquid, hydrocarbon-rich liquid, and hydrate were measured, as well as the percentagesof methane and propane in the hydrate. The data indicate that natural gashydrate behaves as a solid solution and that pentanes and heavier hydrocarbonsdo not enter into the solid phase. Vapor-solid equilibrium constants arepresented that permit the approximation of the conditions for hydrateformation, from the composition of a gas.

Introduction

Natural gas hydrates have been the object of considerable research in recentyears, because of the trouble they have caused in the natural-gas andnatural-gasoline industries. Natural gas hydrates are white crystallinecompounds of water and gas, which, under pressure, exist at temperaturesconsiderably above the freezing point of water. Because of the relatively hightemperatures at which the hydrates exist, they become a nuisance inhigh-pressure gas operations where water is present, since their formationcauses partial or complete plugging of valves and pipes. From a practicalstandpoint, the trouble incident to hydrate formation has been solved bydehydration of the gas before it enters the plant or pipe line, or by otherremedial measures.

Extensive work on gas hydrates in the latter part of the nineteenth century, by Villard and others, gave data on methane hydrate and on ethane hydrate.Schroeder summarized these theoretical studies, Hammerschmidt introduced theinformation on gas hydrates to the gas industry, and Deaton and Frost gathereda considerable number of data on the behavior of natural gas hydrates. Recentpapers have extended both the data and the theory of these hydrates.

At present, data are available on temperatures and pressures of hydrateformation for pure methane, ethane, propane, n-butane, methane-ethane mixtures, methane-propane mixtures, methane-butane mixtures, and some 15 natural gases, all in the presence of excess water. However, up to the present time no methodhas been available for predicting the temperature at given pressures or thepressure at given temperatures at which natural gases will form hydrates ifsaturated with water.

T.P. 1371
Pressure Prediction for Oil Reservoirs
Authors: Bruce W.A.
Published: June 2014

This paper presents the essentials of a mathematical method of studying thepressure beha vior of an oil reservoir as the fluids are withdrawn. Methods areshown whereby the behavior of a reservoir can be used to predict the futurerelationship between withdrawals and pressure. The oil reservoir is consideredas a small part of a large porous continuum, which contains for the most partwater. The expansion of this water resulting from a decrease of pressure in theoil zone causes a movement of water that is an important factor in therelationship between fluid withdrawals and reservoir pressure. Examples aregiven to illustrate the methods of pressure prediction for a circular reservoircontaining undersaturated crude, the pressure distribution over a field that has a uniform production rate, theeffect of a fault line near a field, the mutual interference of near-by fields, and the perturbing influence of a gas cap. Applications of the analysis towell-spacing problems are shown.

Introduction

The pressure-prediction methods to be described here are based upon theconception of an oil pool as a small part of a large porous continuum, containing for the most part water. The formation containing this water may bethought of as extending over an area of many square miles and having one ormore small bodies of oil or gas trapped in high spots or reservoirs. It will betreated as having the general aspect of a thin, flat sheet with an over-alltilt to the horizontal and with numerous small high spots, tight zones, andirregularities. This porous continuum will be treated as being much moreextensive than the oil or gas zones, but will be recognized as terminating atsuch large boundaries as a general fault, outcrop, unconformity, orpinch-out.

Throughout the greater part of this limited porous continuum it is likelythat there is a hydraulic connection. If this is true, the removal of fluid inone place will cause a disturbance that eventually will travel to all parts ofthe continuum.

This picture has led to the recognition of water as the major fluid in theporous continuum and in many cases the expansive nature of this water as themain driving force producing the oil. The next step is the solution of thegeneral problem of compressible liquid behavior in porous media.

T.P. 1454
Analysis of Reservoir Performance
Authors: Old R.E.
Published: June 2014

Through the use of pressure and production records, formation properties andbottom-hole sample data, the performance of an oil reservoir may be studiedanalytically to define and evaluate the natural forces acting on and within thereservoir. Use is made of material-balance methods and the equations fornatural water encroachment to estimate reserves. Methods for calculation ofpressures are given.

A study of the Jones sand, Schuler field, Arkansas, has been made and isgiven here to illustrate the value of the methods discussed.

Introduction

With the decreasing rate of discovery of new oil reserves, attention isnecessarily focused on the efficient development, evaluation, and production ofexisting reserves. From the nation's viewpoint, the necessity of conservingresources is obvious. From the operator's viewpoint, the problem is to lengthenthe period of profitable operation, in an attempt to increase the return on hisinvestment. To do this the operator must take advantage of the natural forcesacting on and within the reservoir. Natural water encroachment, the nemesis ofprofitable operation in the past, can be and is being harnessed to produce agreater oil recovery during the stage of flowing production. Proper evaluationof water encroachment rates and a fuller understanding of reservoir behaviordictate the appropriate production procedures.

Complacency in hit and miss production is obsolete. Oil production must andwill approach the efficiency of other businesses, such as manufacturing. Amanufacturer will not place an article on the market until he has fullyinvestigated the processes involved, additional investment in equipment, costsof production, and expected profits. These may be modified by actual experienceat a later date, but at least he begins with an idea of expected return. It isjust as logical that an oil operator should investigate these same factorsduring the development and the early period of production of an oilreserve.

The complexity of the problems existing in oil reservoirs should not beunderestimated. Conversely, they should not be regarded as insoluble. Manycompletely defy solution, but there are others that can be solved completely orattacked intelligently to yield approximate results.

T.P. 1529
Gravitational Drainage of Liquids from Unconsolidated Wilcox Sand
Authors: Stahl Roscoe F. , Martin W.A. , Huntington R.L.
Published: June 2014

A marked gravitational segregation of liquid has been observed to take placein a number of volumetric fields toward the later stages of their oil-producingperiods. This phenomenon has been pronounced in thick, highly permeable sandformations such as those of the Wilcox zone in Oklahoma City. This observationhas prompted considerable research directed toward the semiquantitativedetermination of the equilibrium saturation distribution of oil verticallythroughout a formation at final depletion. In this paper, data are alsopresented showing the transient distribution of liquid at different stages ofthe depletion period. Other experimental results show the effect of temperatureon the drainage rates of water, Wilcox crude oil, and a close-cut heptanefraction. Intermittent drainage of liquid produced saturation gradients thatmight well be expected from the flow theories involved. Yields of the variousliquids varied from 50 to 75 per cent of the original fluid content of thesand-packed (4 in. by 8 ft.) vertical tube.

Introduction

In certain volumetric oil fields the performance of the reservoir during thelatter part of its producing life is governed to a large extent by the downwardmovement of liquid due to the force of gravity. This is especially true offormations having thick or tilting beds of uniformly high permeability, free ofshale breaks. Leverett and Katz have presented original data and discussed thetheory relating to the capillary and gravitational forces acting on liquidscontained in a sand body. These investigators have pointed out the importanceof such studies in the estimation of future reserves as well as the originalfluid content of a reservoir.

In this previous work, no data have been reported showing the history ofsaturation distributions during the drainage period. Since a knowledge of thesetransients is helpful in obtaining crude oil from such a reservoir, the authorshave obtained these data during this investigation.

T.P. 1548
The Nature of Hastings Drilling Mud by Supercentrifuge and X-ray Analysis
Authors: Fancher George H. , Oliphant S.C.
Published: June 2014

Two samples of drilling mud from the Hastings oil field, Texas, were tested, and the solids in each were separated into small fractions of a limited rangein particle size. The mineral composition of each fraction by X-ray analysis isreported, and the results are interpreted in relation to other measuredquantities, such as the physical properties of the original samples and thedensity of the various fractions. It was found that only 7 to 8 per cent byweight of the solids was of colloidal dimensions and that neither of thesamples contained montmorillonite but did contain illite. Considerable calcitewas also found. These data should be useful to the geologist interested in theorigin and history of sedimentary strata as well as to the petroleumengineer.

The physical and chemical properties of clay suspensions, it is difficult todefine precisely a drilling mud, and much more difficult to say whatconstitutes a good mud.

It is generally believed that the smaller particles of a drilling mud greatlyaffect its physical properties. In fact, it is customary to blame the colloidsin a mud for nearly everything that goes amiss, because colloidal propertieshave effects out of all usual proportion on viscosity, filtration rate andreaction to electrolytes. It is germane to know whether drilling muds possesscolloids and if so, the quantity and kind.

Introduction

The questions, What is good drilling mud? What constitutes bad drilling mud?are pertinent, because the proper use and control of drilling fluids has been afactor of great importance in the successful drilling and completion of oilwells since the days of Captain Lucas. Adequate control of the characteristicsof drilling fluids has assumed greater significance comparatively recentlybecause of the problems introduced by caving formations in deep wells, costlyblowouts and impressive mud bills.

T.P. 1531
Deeper Drilling Prospects in the Mid-Continent
Authors: Denison A.R.
Published: June 2014

Several productive areas in the Mid-Continent are broadly and briefly examinedwith respect to the present depth of drilling on productive structures, and thethickness of sediments remaining untested. Evidence is offered to show that avertical mile to two miles of untested but prospective formation remain withinreach of the drill. In no case would a well deeper than 15,000 ft. be required, and in most cases to no greater depth than 10,000 ft. Recent outstandingsuccess of deeper prospecting in West Texas demonstrates the merits of deeperdrilling on known structure.

Introduction

New fields discovered during 1942 equaled or exceeded the number in anypreceding year. The total amount of oil found by these discoveries was lessthan in any previous 'year, for which accurate records are available. Thismeans that the pools now being discovered are much smaller than in past years.This is to be expected, since the prospects available during 1942 were largelythose overlooked in the earlier years and therefore represent a second or thirdorder (in quality) of structural feature. This failure to find pools of goodsize and quality raises grave doubt as to the security of our future oilsupply. With military needs rising almost daily, and the period of heaviestconsumption in our war effort still in the future, there is even a growingdoubt as to our ability to supply the amount needed for our ultimate victory.This does not mean that our reserves are inadequate, but rather that our"capacity to produce" may be inadequate. Lacking large fields withflush production, our capacity to produce is rapidly approaching our currentneeds, Since the industry is unable to find the large new fields necessary tokeep a safe margin of "capacity to produce," other means are needed. Itseems obvious that one of these should be deeper prospecting on the large, proven, productive structural features now known.

The exploratory wildcat is drilled primarily in search of a trap and the reasonfor failure to find oil and gas in nine out of ten cases is due to the absenceof a suitable trap under the drill site. Therefore, deeper drilling on a knownstructural feature that is productive largely eliminates the greatest hazard inwildcat drilling. While by no means all the oil known today is found instructural traps-in fact, some have estimated that less than half is so locatedthe fact remains that structural traps are far more commonly the oil fieldsthat have multiple horizons of production superimposed one over the other.Outstanding examples are the Eldorado field in Kansas, the Tonkawa and Cushingfields in Oklahoma, the Louden and Salem pools of Illinois, and the richest andmost prolific of all structural traps, the Long Beach, Ventura and othersimilar fields of California.

T.P. 1650
Engineering Features of the Schuler Field and Unit Operation
Authors: Kaveler H.H.
Published: June 2014

A summary of the reservoir engineering and related geologic data on the Schulerfield, Union County, Arkansas, is presented here in a manner intended tointerest both technical and nontechnical readers.

The Cotton Valley formation and the Reynolds oolite are oil-productiveformations in the Schuler field, but the Jones sand pool, at a depth of 7500ft., developed with I46 wells on 20-acre spacing, is the reservoir of principalinterest.

The Jones sand sandstone reservoir is an anticlinal trap typically gas-drive ordepletion type in performance. The core analyses from 88 per cent of the wellsdrilled, together with drilling time and electric-log data, yield an accurateestimate of the "productive" sand thickness and its areal distributionover the pool. Accurate production statistics, monthly reservoir-pressuresurveys, and bottom-hole sample analyses when correlated by the "material-balance equation" show unusually good agreement with thatprinciple. Estimates of oil initially in place made by the material-balancemethod and the sand-volume method are in good agreement at 1I6 to I20 millionbarrels. The reservoir-pressure history of the pool reflects the reaction of areservoir to production, proration and secondary-recovery practices.

The cost of the extensive program of reservoir study in the Jones sand pool hasbeen estimated, in order to emphasize the value derived from such an investmentthrough better understanding of a reservoir's reaction to productionpractices.

Unit operation of I40 of the I46 Jones sand wells made possible an effectiveunitized gas injection pressure-maintenance program. Reservoir-pressure declinewas arrested, natural flow was maintained, and pumping and lease equipment wereconserved. An increased ultimate recovery of 20 million barrels beyond theestimated 34 million barrels primary recovery is indicated at present.

Extension of the Jones sand unit to include the undeveloped Cotton Valleyformation will permit additional recovery of otherwise uneconomic reserves ofoil through wells no longer required in the Jones sand operations.

Introduction

The Schuler field comprises approximately 4000 acres in and about sec. 18, T.Ig S., R. 17 W. in west central Union County, Arkansas. Three reservoirs areproductive of oil and gas: the Cotton Valley formation, the Jones sand, and theReynolds oolite section of the Smackover limestone. The Jones sand pool is themost important reservoir from an engineering viewpoint. It possesses thetraditional and somewhat classic characteristics usually associated with ananticlinal trap. Development and operations have followed the dictates ofadvanced 'engineering practices. maintenance operation now being carriedout.

T.P. 1605
Estimated Consumption of Petroleum Products in the United States after the War
Authors: Burrill C.L.
Published: June 2014

The forecasts presented in this paper constitute an attempt by the writer topredict the pattern of the consumption of petroleum products in the UnitedStates during the period of transition from war to peace. Although, inpreparing the estimates, secular trends were not overlooked, greater emphasiswas placed upon considerations of a cyclical character, or upon influenceswhich might be peculiar to parts of the period. The estimates do not extendbeyond the year 1950 because by then conditions in the industry should havereturned to normal.

The consumption of petroleum products is affected, of course, by changes in thecondition of business in general. Before estimates of petroleum consumptioncould be prepared, therefore, it was necessary to predict the pattern ofgeneral business during the period under review, particularly the economicseries that in the past have shown the closest relationships with petroleumconsumption.

It is the writer's view that business activity in this country (as measured byindustrial production) will be higher on the average during the period betweenthe end of the war and the year 1950 than it ever was before during a peacetimeperiod of the same duration. When the war is over, consumers will have savedamounts of money that will be very large as compared with any previousaccumulations. There is little question, therefore, as to the financial abilityof consumers to purchase goods. The production of many durable consumers'goods, such as automobiles, refrigerators and radios, has been completelystopped since early in the war; also, many semidurable and nondurableconsumers' goods have not been available in the quantities or the qualitiesdesired. There is considerable need, therefore, for consumers to purchase goodsafter the war. The important question is whether consumers will purchase goodsin large enough quantities to keep our economy running at a high level. Thewriter answers this question in the affirmative. The mere existence of verylarge consumer savings lends considerable support to this view because, withsuch backlogs of "security," consumers can afford to spend more oftheir current earnings than they otherwise could. Also, several polls have beentaken, which indicate that consumers expect to buy large quantities of avariety of goods. Some of the savings, therefore, probably will go into currentconsumption. Even though this percentage is relatively small, so that the bulkof the funds accumulated by consumers during the war continues to remain assavings during the period under review, spending should be great enough tostart the production cycle and keep it going at a relatively high rate for afairly extensive period.

T.P. 1730