bluuebunny/crossref_metadata_2025 huggingface dataset:
Deep-well Pumping in California
Authors: Marsh Hallan N.
Published: June 2014

The subject of this paper is apt to bring to mind wells ranging from 6000 toover 8000 ft. in depth. However, it is uncommon to pump wells at depths greaterthan about 5000 ft. Fig. 1 shows the number of wells being pumped at variousdepths by one company in Southern California.

A few companies have a very few wells pumping at depths greater than this.This paper will deal with wells between 3000 and 5500 ft. in depth. MostCalifornia oils at these depths are between 25? and 35? gravity. The subject isso broad that it will be necessary to omit many interesting phases, and totreat others very briefly. Power, power transmission equipment, powerefficiency, counterbalancing, sucker rods, pumps and volumetric efficiency willbe discussed.

Power

As a source of power, the 50/20-hp. electric motor is generally preferred.Input is generally between 10 and 25 hp. Due to the unevenness of the load, aninput of 20 hp. on the low range is generally about all that these motors willcarry without overheating, in spite of their overload capacity.
Capillary Phenomena as Related to Oil Production
Authors: Tickell Frederick G.
Published: June 2014

Petroleum engineers are displaying considerable interest in thosefundamental properties of matter and energy that control the phenomena of oiland gas production. The subject is a difficult one to investigate by laboratoryexperiments for two reasons:it is impossible to reproduce in thelaboratory the scale of forces and dimensions that exist in the undergroundreservoir;if we attempt to scale down the dimensions we are unable toreduce all proportionally.

It is as if we tried to construct a model blastfurnace for the reduction of iron ore, and reduced all lineal dimensions. Weshould find that the interstices between the miniature chunks of ore would notpermit rapid transfer of gases, that combustion and heat transfer would nottake place as in the full size furnace and that, in short, the contraptionwould not work. Just so, when we attempt to make a reduced scale oilfield wefind we must have, not only miniature reservoir and miniature wells, but"miniature" sand, oil, gas, etc. Much valuable work, however, has been donealong these experimental lines and more will no doubt follow, but investigatorsshould bear this point in mind and strive to attain dimensional homogeneity anddynamical similarity in order that their conclusions may be translated intoterms applying to the oil reservoir. As Gibson says, "These conditions areattained when all terms of the physical equation have the same dimensions…when all corresponding particles of the two systems trace out similar paths andwhen the velocities are such as to make all corresponding forces acting on twosuch particles in the same ratio." It is the purpose of this paper todiscuss the mechanics of fluid movement as it pertains to the oil pool and topoint out the complexity of the laws of fluid delivery under the conditionsoften found.

We have to do, fundamentally, with confined fluids, possessing potential energywhose expenditure is restricted by certain properties of the confining mediaand of the fluids themselves. The equation of motion and time is completelystated when we can assign values to the propulsive
Proration in Texas
Authors: Donoghue David
Published: June 2014

The efforts towards curtailment in Texas have been successful, despite thegreat area covered and the wide variety of oils offered. There are, of course, examples of noncooperation, perhaps of absolute indifference, but of such itcan at least be said that they have benefited from the restrictions imposedelsewhere.

The prevention of waste is the legal background for proration in Texas. Thelegislature in 1899 passed the first laws to prevent waste of oil and gas.Subsequent legislatures, especially those of 1905, 1913 and 1917, undertook toregulate the development and transportation of oil and gas to the end thatwaste would not occur. In 1917 a constitutional amendment was submitted to thepeople, providing that natural resources of the state should be conserved andrequiring that the legislature pass appropriate laws. This amendment wasadopted, and the Acts of 1919 and 1929 have been passed, and these have had theeffect of making a rather elaborate plan for the conservation of oil and gasand their protection against waste, In 1930 the new pipe line act, designed toprovide for ratable purchases, was passed.

The administration of these laws has been placed under the Oil and Gas Divisionof the Railroad Commission of Texas. The Commission can only consider actualwaste, not economic waste, The various proration plans in use in the state, while differing in efficiency, are based on engineering principles. In theproration of flush fields, the limiting of drilling and the steady productionof oil under restriction are the principal points involved, and these methodsare entirely different from those which prevailed until recently in theOklahoma City Pool, where apparently nothing beyond the restriction ofproduction on a time basis was attempted.

There is little to say in defense of proration in the older and smallerproducing areas in Texas, except that, inasmuch as the market outlet has beenreduced, proration distributes the market ratably among the producers.
An Economic Comparison of Developments in the South Field Oil-producing Region of Mexico
Authors: Knight Oliver B.
Published: June 2014

The producing formation in the South Field, or "Golden Lane"structure of Mexico, is a buried ridge of reef limestone of Comanchean ageoverlain unconformably with sediments of Upper Cretaceous, Eocene andOligocene. The structure extends in a long sweeping arc, with the convex sidetoward the west, from San Geronimo, Vera Cruz, to San Isidro, south of theTuxpam River, which it crosses at the town of Alamo. It is 52 miles long andaverages 3/4 mile in width.

The surface of the producing formation of EI Abra limestone consists of aseries of minor parallel highs which are separated longitudinally by synclinaltroughs and laterally by structural saddles. The presence of these highs hasbeen of utmost importance in the development of the field, especially in recentyears when the salt-water level has risen above the synclines and confined theoil to the isolated highs. In many cases, faulty information and interpretationof the subsurface has resulted in drilling costly dry holes and salt-waterwells.

Development

The development of the Golden Lane was started by the Mexican Eagle Oil Co. in1906. San Diego No.3, usually known as Dos Bocas, the first producing well onthe structure, was completed on July 4, 1908. This well came in unexpectedlyfor an estimated daily production of 129,000 bbl., and, as the casing was notproperly set, the well flowed wild into the Tamiahua Lagoon, causing a loss ofseveral million barrels of oil. In flowing wild the well formed a crater whichcovers an area of 48 acres, out of which salt water and small quantities of gasstill flow. Casiano No.2, the Huasteca Petroleum Co., which yielded 200 bbl. ofoil daily, and which was completed in November, 1909, was the next producingwell to be drilled on the structure. In 1910, the same company completedCasiano No.7, with an initial production of 50,000 bbl. daily, and CasianoNo.1, which produced 200 bbl. daily. In the same year, the Mexican Eagle OilCo. completed its Potrero del Llano wells 1, 2 and 4, with initial productionsof 500, 400 and 100,000 bbl. respectively.
Increasing the Ultimate Recovery of Oil
Authors: Shaw S.F.
Published: June 2014

The theory that maintaining a high back-pressure on the oil sand lowers theviscosity of the oil has been generally accepted. The theory has also beenadvanced that lower viscosity permits the oil to be moved through the sand tothe well at an expenditure of less gas per barrel of oil than would otherwisebe required. It seems reasonable to assume that production of oil at theminimum gas-oil ratio will result in a greater ultimate recovery of oil.

During the past five years the writer has acquired data on thousands of testsmade on wells to determine the best rate at which to produce them. In themajority of cases reduction in back-pressure did not definitely increase thegas-oil ratio. The information obtained from these tests has raised doubt inthe mind of the writer as to the correctness of the theory that loweredviscosity results in lower gas-oil ratios and in higher ultimate recovery ofoil. The reasons that explain the results obtained in these tests cannot yet bedefinitely stated, but the hypothesis is being tentatively assumed that thereare other factors which outweigh the influence of viscosity.

Energy In Gas Moves Oil To Well

The general opinion is that in most cases it is the energy in the gas thatmoves the oil to the well. In wells flowing naturally it is also the energy inthe gas that lifts the oil to the surface. In a flowing well, there are twovery distinct operations:Moving the oil through the sand to the well.Lifting the oil to the surface.

The more important function of the gas is that of moving the oil to the well.Means for lifting the oil can always be found once it has been delivered to thewell.

Principles Involved In Lifting Oil

A well that flows naturally is the same as a gas-lift well except that all ofthe gas is supplied by the oil reservoir.
Properties and Treatment of Rotary Mud
Authors: Marsh Hallan N.
Published: June 2014

The subject of mud sounds so simple, uninteresting and unimportant that ithas failed to receive the attention that it deserves, at least as applied tothe drilling of oil wells. As a matter of fact, it is one of the mostcomplicated, technical, important and interesting subjects in connection withrotary drilling. In 1923, R. E. Collom said "It should be possible toestablish certain physical standards for mud fluid," but while considerablework has probably been done on the subject before and since that time, andnumerous articles have been written, the progress of general knowledge of thesubject and the application of better practices have not kept pace with otherdevelopments in rotary drilling, and physical standards cannot be considered asestablished.

Mud is apt to be thought of as an accessible and cheap material, but itscost is likely to be an important factor in the total cost of drilling a well.Some wells "make" most of their own mud out of the formations drilled, but in most cases a great deal of mud-making material has to be supplied frommore or less distant sources. Expenditures for mud materials by one Californiacompany totaled practically one-quarter million dollars during 1929 andaveraged about $13 per rig per drilling day, or about $2000 per well. Underunfavorable conditions, mud cost may reach many times this figure. Parker2 saysthat in the Hobbs, N. M., field "as much as $75,000 has been spent on onewell alone for mud and mud-weighting compounds." Presumably this is anexceptional case. Unit cost of mud fluid will range from 10 c. per barrel, where suitable material is close at hand, to $1 where crude material isavailable at moderate price but must be hauled long distances, and on up to asmuch as $11 per barrel where high gas pressure requires the use of specialprocessed weighting material.

The cost of mud pales into insignificance, however, when the results ofusing improper mud are considered. Blow-outs and lost circulation are obviouslythe result of inadequate mud. Stuck drill pipe, whether or not twisted off, inmany if not most cases probably is caused by cuttings settling out of the mudor the mud itself precipitating.
Proration in Texas in 1932
Authors: Donoghue David , Baker E.
Published: June 2014

Legal and legislative matters constituted the outstanding features ofproration in Texas in 1932. From East Texas emanated most of the political, legal, technical and industrial activity. Conroe and Thompson developed intofields of major importance. Proration orders were issued by the RailroadCommission on many of the producing fields of the Gulf Coast and West Texas notcovered in previous years. In Yates, Penn Pool, Winkler, Van, the Panhandle, North Texas and West Central Texas there were no changes of importance, exceptin allowables. New proration schemes were introduced in East Texas, Conroe, Thompson, Saranosa, Government Wells, Tuleta and Howard-Glasscock. Littleprogress was made in administration or technical development.

Legal And Legislative Matters

Proration first began in Texas in 1927 as a voluntary attempt to divide themarket outlet of a field on an equitable basis. The statutes then in existencewere considered somewhat archaic and the Railroad Commission's authority waslimited. Subsequent efforts to strengthen the laws were not wholly successful. The 1929 Conservation Act made no mention of market demand but declared thatthe term "waste" did not mean "economic waste." With thepassage of the Pipe Line Act of 1930, providing for ratable purchasing, it wasthe opinion of many lawyer that a legal means of proration had been found. The1931 law had the same provision as that of 1929 with respect to economic wastebut specifically prohibited limiting of production to market demand. The lawpassed Nov. 12, 1932, omitted reference to economic waste and specificallyprovided for limitation of production to reasonable market demand.

Vigorous attacks were being made in State and Federal Courts on theconstitutionality of the laws and the validity of the Commission'sorders.

In Peoples Petroleum Producers, Inc. et al. vs. Lon A. Smith et al., which hadbeen heard before a three-judge U. S. District Court in Houston on May 28, 1932 and again on Sept. 19, the Court's decision for plaintiffs, released Oct. 2, influenced in a large measure the calling of the Legislature and the passage ofthe Market Demand Law on Nov. 12.
Effects of Temperature on the Viscosity of Some Gulf Coast Drilling Muds
Authors: Craft B.C. , Exner J.D.
Published: June 2014

With the introduction of rotary drilling in the Gulf Coast area, somethirty-two years ago, and its subsequent spread to other producing localitiesin the United States, there has been a constant change in the design ofequipment. Only the general features remain, namely the rotating drill stem andthe circulating mud. Only recently have the properties of mud and theirbehavior received attention from petroleum engineers, but circulating problemsin present deep drilling demand further study and understanding.

It is the purpose of this investigation to determine the relative changes inthe apparent viscosity of muds with changes in temperature and to discoverother physical effects due to heat.

Very little information has been published regarding the effects of temperatureon the viscosity of drilling muds. Maust states: "The viscosity of mostmuds is decreased on heating, but the interesting thing is that the degree offlocculation is also increased on heating. There will be a greater tendency toseal off formations at high temperatures than at low temperatures." Withregard to the effect of temperature on viscosity and yield point, Herrickstates: "The variation of yield point and viscosity of mud with temperature….. is not very clearly brought out by the data available. Both appear todecrease slightly with increasing temperature up to 2000 F." Theexperimental results presented in this paper further emphasize thispoint.

Two types of viscosimeters are available for measuring the apparent viscositiesof drilling muds: the efflux tube type as used by Herrick and Marsh, and thetorsional type such as the McMichael or the Stormer viscosimeters.
Instrument and Equipment for Recording Subsurface Pressures
Authors: Parks Ernest K. , Gibbs C.W.
Published: June 2014

In 1929 the Standard Oil Company of California commenced the development ofa device for obtaining temperatures and pressures in flowing and shut-in wellsand of suitable running equipment for such a recorder. Although simple inprinciple, the recorder has required much experimental work in its development.The various problems have now been solved to such an extent that it is believedthat the apparatus affords a sturdy and reliable means for obtaininginformation regarding depth pressures,-apparatus that may be turned over to awell gang for routine operation.

As an example of the rough usage the device will withstand a recent incidentmay be cited. Owing to failure of the lowering line at the conclusion of a runa recorder was dropped some 6300 ft. through 2~-in. tubing filled with gassyoil. The device was fished out undamaged and with the pressure record intact, although the instrument had been subjected to a, pressure greater than 2300 lb.per sq. in. for some 24 hr. after impact at bottom.

Description of Recorder

The instrument is of the continuous recording loaded spring type (Fig. 1).Temperature is not recorded continuously but is obtained by maximum recordingthermometers in an auxiliary thermometer well. The entire instrument assembly, from bottom of the recorder to top of the socket, is 6~ ft. long and weighsless than 25 lb. The maximum outside diameter of the recorder shell is U:4:in., and all attachments need be no larger. This permits lowering the deviceinside 2-in. tubing.

The operating principle is simple. The well pressure acts upon a piston Aresisted by the extension of spring B. The spring deflection is recorded by astylus C upon paper within the recording drum D.

Springs.-To improve accuracy at lower maximum well pressures fiveinterchangeable spring assemblies are used. These have maximum pressure rangesof from 250 to 5000 lb. per sq. in.
A New Method for Measuring Vented Gas
Authors: Rader C.M. , Feemster R.A.
Published: June 2014

Because of the necessity for taking regularly occurring open-flow tests inprorated high-pressure oil fields, much gas is turned to atmosphere by way ofvertical vent lines leading away from the oil and gas separator. In the past, measurement of such gas has been accomplished by several methods, usually byuse of the open-flow Pitot tube. The use of the closed-flow Pitot tube has beenavoided apparently chiefly because the ordinary vent-line hook-up makes itnecessary to apply the instrument closer to a bend, valve, or obstruction inthe pipe than is recommended by rules of good practice.

The many advantages that would result from the application of the closed-flowPitot tube prompted investigation of the actual effect upon quantity rate offlow measurements computed from data obtained with the tube in a normal workingposition, which is closer to the tee at the base of the vent riser than isusually considered as giving highly accurate results. An effort was first madeto compare the results thus obtained to those under ideal conditions and athigh velocities.

To make this comparison, knowledge of the characteristics of gas flowing atvery high velocities is essential. Research for such information indicated thatlittle or no work had been done that would give data necessary for such acomparison, therefore the problem was changed to a test designed to determinethe relationship between quantity rates of flow as measured by an orifice meterand a Pitot tube placed at the center of a pipe eight diameters from a tee orell at the base of a vent riser, through which gas is flowing under lowpressures at very high velocities.

To determine this relationship, a series of tests was run on a number of 8-in.iron-pipe vent risers in which the Pitot tube data were taken at the positionas stated above. Gas from a wet-gas gathering system was passed through anorifice meter setting and thence to atmosphere by way of the vents.

Data were taken simultaneously from the orifice meter and Pitot tube from whichcomputations for comparisons were made. The actual method of comparison isdiscussed later in this paper.
Estimation of Petroleum Reserves in Prorated Fields
Authors: Judson Sidney A. , Easton H.D. , Schaeffer W.A.
Published: June 2014

Restriction and proration of petroleum production have increased materiallythe difficulties attendant upon the estimation of reserves, particularly inlarge, "flush" fields. Such practices preclude the use of decline orother curves, from which, under capacity production conditions formerlyprevalent, much could be learned as to the ultimate recovery to be expectedfrom a given field or lease therein. In restricted fields that would produce atmany times the low rate allowed by the regulations in force if allowed to flowwithout restraint, one is forced to use other information than productionperformance to predict the volume of oil recoverable. Examples are: atKettleman Hills, California; the Conroe, Van and East Texas fields, Texas; theIowa field, Louisiana.

It is beyond the scope of this paper to apply a definite method to thedetermination of the reserves in any actual field, therefore the discussionwill be limited to a consideration of available methods and an enumeration ofimportant factors governing the accuracy of such estimates. The problem is todetermine not only oil in place but recoverable oil in place, for a given fieldor tract, which is complex and depends not only on the characteristics of thereservoir but also on the plan of development, the production allocationscheme, the rate of production and many other factors. Many data mustnecessarily be considered, weighed as to importance, and assigned quantitativevalues. Estimates of recovery in prorated fields have been discussed by Brace, Shaw, Snider and others.
Estimation of Developed Petroleum Reserves
Authors: Albertson M.
Published: June 2014

The purposes of this statement are to define a problem that exists in regardto the estimation of developed petroleum reserves, to analyze the problem in anabstract manner, and to discuss it as an introduction to certain papers thatfollow. The problem is to devise and develop a suitable procedure to permitmore accurate estimates of developed petroleum reserves. Part of the problem isto make such estimates available earlier in the life of any particularpool.

The problem of securing more accurate estimates of developed petroleum reservesexisted prior to curtailment of production. With curtailment, however, theproblem became acute, some of the more prominent reasons being asfollows:The standard method of estimation depended on production decline curves.This method is inapplicable while curtailment prevails and available methodsare insufficient.The retarding influence imposed by wide open flow conditions uponoverdevelopment is absent. Great losses of capital by overdevelopment can nowoccur before realization of the true situation occurs, or before effectivesteps can be taken to stop such wastage. This increases the need for early, accurate estimates.Above-ground stocks have diminished and the equivalent of such supply tendsmore and more to be retained underground in the natural reservoirs. It becomesincreasingly necessary to know accurately the amount of these stocks.

To direct attention to an additional point of different nature: improvedaccuracy of reserve estimation can be obtained. only by closer scrutiny of thefactors that determine recovery. This examination and the resulting efforts tomeasure the effect of these factors in terms of ultimate recovery must tend toimprove ultimate recovery.

The statements regarding the acute nature of the problem also indicate to someextent the importance of the problem and the necessity of finding asolution.
Use of Data Oil the Build-up of Bottom-hole Pressures
Authors: Muskat Morris
Published: June 2014

In preparing a well for pumping, observations are often made of the fluidlevel in the well bore or bottom-hole pressures at various times beforeequilibrium has set in. From a qualitative point of view one may immediatelyinfer that if the rise in the bottom-hole pressure or fluid level is rapid thepermeability of the sand about the well bore is large, and converse conclusionmay be drawn if the rise is slow. However, a more quantitative estimate willgive additional information of value, as will be shown in this paper.

To derive such an estimate we may proceed as follows. Let h be the fluidheight, above the sand face, at time t, and let "Yo be the average densityof the fluid that enters the bore. The bottom-hole pressure, for a fluid heighth will therefore be p = "Yogh, neglecting, of course, the friction drop inthe well bore, while the fluid is rising, as may be justifiably done for mostpumping wells.

If a is the free area of the open-flow string-assumed to be uniform-the rate ofproduction from the sand during the rise of fluid will be:ah a apQ = a- = - - = f(p)at "Yog dt

where the last part of the equation merely indicates that, in general, theproduction rate Q must be considered as a function of the back pressure, and isdetermined by it alone. In fact, equation 1 shows that if the rate of rise ofthe pressure or fluid level is determined as a function of the height of rise, or p, for a number of values of the latter, this functional relation between Qand p will be immediately given.

Conversely, if we know this functional relation, the rate of increase of p or hmay be predicted, or, by observing the rate of rise of p or h some of theconstants of the sand may be determined.
Spacing of Oil Wells
Authors: Foley Lyndon L.
Published: June 2014

The proper spacing of oil wells is a problem of vital importance to the oilindustry. Conservation demands a maximum recovery, while economicconsiderations attach primary importance to profitable extraction of oil.Formulas have been evolved, which attempt to solve the spacing problemmathematically, using reservoir characteristics as factors. Comparisons havebeen made of fields producing from supposedly similar sands, which have beendrilled to varying densities, and also of different leases in the same field.Intermediate wells have been drilled in old, depleted fields to test theefficiency of drainage by the original operation. Intermediate wells have beendrilled also to obtain cores of the depleted sand for analysis, from which tolearn the degree of efficiency of extraction. The problem is being attacked bymany students, and along several different lines.

Unfortunately, the fields now depleted were produced generally withoutrestriction, and conclusions drawn from them may not apply to fields operatedunder restricted production. Reservoir conditions in a restricted field, especially reservoir pressures and pressure gradients within the reservoir, arequite different from those in a field produced to capacity.

Many people have held the idea that the closer the spacing, the greater therecovery. This general statement is not always true, as other factors than wellspacing enter into the recovery problem. Cutler, 5 who has been quotedfrequently by advocates of close spacing, limited his conclusions to gas-drivefields, and to the particular fields and spacings that he investigated. Hilland Sutton 7 analyzed four tracts in the Powell field; the tract most closely drilled had the third largest recovery peracre-foot, and the tract with the widest spacing had the second largestrecovery per acre-foot. A search of the references to well spacing in thepublications of the U. S. Bureau of Mines discloses repeated condemnations ofthe wastefulness of the practice of town-lot drilling.
A Method for Determining the Water Content of Sands
Authors: Botset H.G.
Published: June 2014

A knowledge of the water content of producing sands is becoming ofincreasing importance to the petroleum industry. It is now a generally acceptedfact that practically all oil sands contain some free water. Recent experimentshave shown that an appreciable fraction of the pore space of a sand may befilled with water while oil production from this sand is water-free. Crowtherand Haines, in experiments on electroendosmosis in soils, reported that therewas no endosmotic flow of water when the moisture content of the soil was 14per cent or less, indicating that the moisture content of the soil below 14 percent was held by different forces than the water content above this value. Thisresult is confirmed qualitatively by Dunlap, who found that "as the volumeof water in the voids exceeds approximately 15 per cent of the pore volume, thepermeability of the core to kerosene is markedly reduced." The author hasalso found in other experiments that the gas flow through a water-saturatedsand reaches essentially 100 per cent when the pores of the sand still containfrom 10 to 15 per cent water. The velocities of the flowing fluid in theexperiments cited were comparatively high, so that in practice one may expect, at lower fluid velocities, an even higher moisture content of the sands withwater-free oil or gas production. Thus a knowledge of the water content ofoil-field sands becomes of considerable importance in estimating petroleum andgas reserves, and efficiency of fluid recoveries from depleted reservoirs.

Rapid and reasonably accurate methods of measuring the water content of sandcores have not been described so far in any literature that has come to ourattention. The method described below is developed from methods that have beenused for some time to measure the water content of alcohols. It is anapplication of the fact that in the presence of certain organic liquids such askerosene, carbon tetrachloride, xylol, etc., water and alcohol are only partlymiscible.

T.P. 972
Apparatus for Study of Pressure-volume-temperature Relations of Liquids and Gases
Authors: Sage B.H. , Lacey W.N.
Published: June 2014

An apparatus is described for the measurement of thepressure-volume-temperature relations of pure substances, simple mixtures andcomplex mixtures with an over-all absolute uncertainty, which is usually notmore than 0.2 per cent. The equipment is suitable for studies in the gaseous, two-phase, and liquid regions. The behavior of such systems may be investigatedat pressures as high as 10,000 lb. per sq. in. for temperatures between 700 and 6000 F. The methods of measurement and the construction of the apparatus aredescribed in some detail.

The measurement of the volumetric behavior of multicomponent systems requiresthe simultaneous measurement of the pressure, volume, temperature and weight ofeach component of the system. In the present apparatus a sample having constantweight is investigated at a number of independently controlled pressures andtemperatures, therefore it is necessary only to establish the weight of eachcomponent added before a given set of measurements. This method is indistinction to that in which the total volume remains constant and the pressureis varied by addition or removal of material, the system having variableweight. An objective in the design of the apparatus to be described was todevelop equipment that would yield results involving no uncertainties largerthan 0.25 per cent throughout the range of pressures from 150 to 10,000 lb. persq. in. at temperatures between 700 and 6000 F. Although this over-all absoluteuncertainty of measurement may not appear to be small, it necessitated care inthe plans for control and measurement of each of the fundamental variables. Ingeneral, any uncertainty greater than 0.05 per cent in the pressure, volume, absolute temperature or weight of each component was considered undesirable;therefore the attempt was made to obtain a precision of measurement in eachcase such that the absolute uncertainty would be only half this amount exceptin certain regions near the ends of the experimental range of the variableunder consideration.

T.P. 1127
Petroleum Engineering Education
Authors: Power Harry H.
Published: June 2014

While the attention of all engineering branches is focused today on changesand improvements in the several curricula, we are concerned here with the manyquestions arising in industry and college concerning the preparation for thepetroleum engineering profession. The succession of problems confronting thepetroleum engineer demands a degree of versatility not ordinarily encounteredin other professions. As a consequence, the student cannot acquire mastery ofall the several engineering branches represented in field practice, and as analternative, he has learned to appreciate the value of thorough training in thebasic or fundamental sciences as a preliminary foundation for professionalwork.

While our attention is directed primarily to the training of engineers ineducational institutions, it is necessary that the ultimate education of theprofessional engineer be kept in mind. It is apparent that his success as anengineer is limited not only by his educational and job experience, but by hisnative endowments: mentality, personality and health. The engineer's lack ofjob experiences often proves as much a handicap as the lack of adequate collegetraining. If the final product proves to be satisfactory, both industry andtechnical institutions are to be congratulated. However, if the product isfound wanting, the one most responsible should be apprehended.

Fitness for Profession

For the most part, students of engineering colleges have had their interestsin applied science awakened at a relatively early age. Many of them enteredcollege as a convenient means of acquiring a technical education, butundoubtedly would have had better prospects in a shorter program offered byinstitutions of noncollege grade. The activating motive of practical interestis also strong in students suitable for college training, but in many cases anintellectual interest must be awakened in order that it may survivegraduation.

T.P. 1312
Some Problems of Horizontal Steady Flow in Porous Media
Authors: Putnam John A.
Published: June 2014

Data on the physical and thermodynamic properties of hydrocarbons have beenmade available in recent years but the formal method of applying these data toflow in porous media appears not to have been fully developed. By making usualthermodynamic assumptions and employing existing data on permeability totwo-phase flow, Darcy's law may be applied to obtain the flow characteristicsfor representative combinations of flowing medium and geometry. The numericalexamples presented herein are based on hydrocarbons for which complete physicaland thermodynamic data are available under equilibrium conditions.

Introduction

Thermodynamic data are obtained in the laboratory under equilibriumconditions and their application requires the assumption that equilibrium alsoexists during flow. This assumption is at least usual in engineering analyses, though not easily justified in many instances, and will be followed here. Inregard to hydrocarbons, laboratory experience in determining thepressure-volume-temperature relationships indicates that gas-liquid mixturesmust often be stirred vigorously for periods of 15 to 20 min. before reachingequilibrium. On the other hand, boiling and condensation are known to occur onsolid surfaces and the large surface exposed to the flowing substance by aporous medium may bring about rapid approach to equilibrium. For the purpose ofproviding at least a guide to experimentation and a standard for latercomparison with experimental results, it will be assumed that the phasespresent in cross sections perpendicular to the direction of flow are inthermodynamic equilibrium.

Another assumption usually made in the solution of problems of flow inporous media is that the fluid remains at a constant temperature; i.e., isothermal flow. This assumption is arrived at by considering the porous mediumand surroundings to be an infinite heat source and the rate of heat flow to beinfinite at a boiling front. Its validity depends in large measure upon thecharacter of flow, the number of components, and the physical and thermodynamicproperties of the fluid. However, the assumption of isothermal flow representsa limiting case. The other limit can be represented by the assumption that thefluid is thermally isolated; i.e., irreversible adiabatic.

T.P. 1349
Capillary Behavior in Porous Solids
Authors: Leverett M.C.
Published: June 2014

Knowledge of the theory underlying the behavior of mixtures of fluids inreservoir rocks is essential to the proper solution of certain types ofproblems in petroleum production, but is as yet incompletely developed. Theobject of this paper is to show the application of well establishedthermodynamic and physical principles to these problems, and thus to assist inthe development of the basic theory. For convenience the problems to beconsidered here may be divided into two groups:Static problems, involving only the static balance between capillary forcesand those due to the difference in densities of the fluids; i.e., gravitationalforces.Dynamic problems, involving analysis of the motion of mixtures of immisciblefluids in porous media under the influence of forces due to gravity, capillarity, and an impressed external pressure differential.

Capillary Equilibrium in Sands

Under this heading the static type of problem will be discussed and the resultsof experimental investigations on the capillary properties of unconsolidatedsands will be presented. Although the discussion of this section is, in asense, prefatory to the treatment of problems of mixture flow, the conceptsdeveloped here have considerable intrinsic importance apart from theirapplication to flow problems. For, it is reasonable to postulate that thereservoir fluids are, owing to their long existence in undisturbed mutualcontact prior to exploitation, in substantial equilibrium. It follows thattheir distribution in the reservoir at the time of tapping should be entirelypredictable from the theory of capillary equilibrium, provided certainexperimentally measurable properties of the reservoir rock are known. Knowledgeof the distribution of the several fluids in the reservoir is, of course, helpful in the estimation of reserve, and in other problems.

It is to be emphasized that throughout the discussion of capillary statics itis assumed that the fluids are in equilibrium from the capillary standpoint.Thus, water, where it is referred to as being in a reservoir, will beunderstood to be interstitial water, present at the time of drilling thereservoir, commonly termed "connate" water.

The theory developed here is perfectly general for any porous solid, whether acarefully prepared unconsolidated sand or a natural sandstone from an oilreservoir. At present, however, only problems involving clean, unconsolidatedsands can be made to yield numerical solutions, since only such sands have beenadequately investigated experimentally. Experimental evaluation of thepertinent properties of natural reservoir rocks will permit the extension ofthe numerical treatment to problems involving these materials. We shall nowconsider in some detail the static equilibrium of fluid mixtures in poroussolids; that is, the manner in which the reservoir fluids are distributedvertically when the forces due to capillarity are just balanced by those due togravitation.

T.P. 1223
Completion Practices Related to Well Productivity
Authors: Travers W.J.
Published: June 2014

Several new procedures for completing oil wells have been developed inrecent years. Each method when used where properly applicable promises to be adefinite aid to operators in lowering development or operating costs, or indeveloping the full potentialities of the oil well. Multiple-zone completionsare now frequently used, in contrast to the older practice of setting a solidwater string over each zone to be produced. Gravel packing in unconsolidatedformations often prevents sand troubles formerly experienced where aconventional perforated liner was used. Light-weight bentonitic clay muds andoil-base drilling fluids are definite steps toward eliminating mudding damage, which occurs when heavy rotary mud is used.

Since in each case the new procedure developed is an alternate of olderconventional methods, a problem of selection is presented. The purpose of thispaper is to suggest methods of arriving at these choices and to presentpractical observations that may be of aid in their application.

Introduction

Discovery of deep and prolific oil-producing zones in the San Joaquin Valleyof California during the years 1936, 1937 and 1938 directed attention to meansof improving rates of penetration in drilling. In these years rapid advanceswere made in hole-making technique, and as a result the investment required fordeep development projects was substantially reduced. Improvements introducedduring this period included:larger drilling machinery, with fasterhoisting speeds, higher rotary speeds, and larger circulation volumesbetter mud controlincreased use of alloy steels.

This increasedefficiency of operation has been maintained but further improvement in deepdrilling practice has been less marked in the years 1939, 1940 and 1941. Thediscovery and intensive development of the Wilmington field, in the Los AngelesBasin, which reached its peak in 1938, was influential in shifting the emphasisfrom hole making to completion procedure. Since 1938, California operators havedevoted an increased amount of study to programs for drilling in and completingwells. This new emphasis on completion procedure has, led to the development oftechniques that represent the first successful departures from conventionalmethods to be introduced in many years.

T.P. 1465
Density of Natural Gases
Authors: Standing Marshall B. , Katz Donald L.
Published: June 2014

Density data are reported on 16 saturated hydrocarbon vapors at pressuresranging from 1000 to 8220 lb. per sq. in. and at temperatures ranging from 35?to 250?F. These data have been used to extend the compressibility-factor chartfor natural gases up to 10,000 lb. per sq. in. The relatively large quantity ofhigh-boiling constituents present in high-pressure vapors in equilibrium withcrude oils makes it necessary to include in the analysis of the gas themolecular weight, density, and possibly boiling range of the heptanes andheavier fraction. Relationships have been presented by which the density ofgases may be obtained directly from the temperature, pressure, and gas gravityprovided the gases have a common source or are similar in composition.

Introduction

The densities of natural gases are necessary in many engineeringcomputations in petroleum production and utilization. Gas reserves, changes inreservoir pressure, gradients in gas wells, metering of gases, pipeline flow, and compression of gases are typical problems requiring the density of the gas.A decade ago, engineering computations used ideal gas laws with deviations upto 500 lb. per sq. in. Recent discoveries of pools having pressures up to 7500lb. per sq. in., and installation of pressure-maintenance and recycling plants, have increased the need for data on gas density at high pressures.

Methods Of Computation

The accepted method of computing the density or specific volume of naturalgases is the use of the ideal gas law corrected by a compressibility factor.The method proposed by Kay of correlating compressibility factors for gaseousmixtures on pseudo critical properties appears to be satisfactory for naturalgases. The methane-compressibility factor has been shown to deviatesystematically from the behavior of natural gases and a chart giving thesecorrected factors is available.

A method of computing specific volume of gaseous mixtures from partial molalvolumes has been reported by Sage and Lacey. Complete data for the computationare not yet available for all hydrocarbon gases.

Most of the reported data on gas densities have been in the single-phaseregion removed from the dew point or saturation condition. Since most gases inthe reservoir or while on contact with liquid during flow are saturated, thedetermination of densities under conditions of saturation is particularlyimportant.

T.P. 1323
Dimensional-model Studies of Oil-field Behavior
Authors: Leverett M.C. , Lewis W.B. , True M.E.
Published: June 2014

This paper states the theory underlying the design of two kinds ofdimensionally scaled models of parts of idealized oil fields. One of thesesimulates an oil well and its surrounding sand for a distance of 16 ft.radially from the well. The other model simulates linear flow through layeredsands. Construction and operation of the models are described and typical dataare given. The unique features in the design of the models are:thetreatment of the permeability-viscosity quotient as a single variable andthe use of previously reported experimentally developed relations betweenrelative permeability and saturation and capillary pressure, saturation, porosity, permeability and interfacial tension.

The models at present simulateflow of oil and water only, through unconsolidated sands. They are superior tounscaled models, which may give rise to erroneous conclusions. The models aredesigned to study the desirability of various methods of well completion andthe effects of various factors on recovery of oil from layered sands.

Introduction

Recent work on the fundamental behavior of flowing mixtures of fluids insands has resulted in the development of some new theory in this field, much ofwhich has been presented in previous papers. However, the application of thistheory to the behavior of oil wells or oil fields has proved too complicatedfor ordinary mathematical techniques, except in very highly simplified cases. Apractical solution to this problem appears, therefore, to lie in the use ofdimensionally scaled models of elements of oil fields.

The object of this paper is, first, to present the theoretical andexperimental basis of the design of such models, and, second, to describe theirconstruction and operation. Experiments now under way on the models alreadybuilt will yield material for other reports, which will be devoted tointerpretation of the results in terms of oil-field behavior.

So far, simple dimensional models of two kinds have been built and are beingoperated. These models represent different parts of an idealized oil field butobey the same underlying theory. The only fluids represented are oil and water, since certain questionable approximations are necessary for gas-liquidsystems.

T.P. 1413
Surface Energy Relationships in Petroleum Reservoirs
Authors: Livingston H.K.
Published: June 2014

A technique has been developed which makes it possible to determine thespreading pressure of liquids and solids, for simple systems. Data for surfacetensions, interfacial tensions, spreading pressures, and contact angles forwater, heptane, and silica are tabulated. These results can be applied to theevaluation of capillary rise and displacement pressure in a petroleumreservoir. Appropriate equations are presented and the application of theseequations is discussed. The presence of surface-active components affects bothcapillary rise and displacement pressure and also seems to influence the rateof fluid flow.

Introduction

The purpose of this paper is to supplement and bring up to date the lastarticle on the subject of the surface chemistry of petroleum reservoirs, thatof Garrison in the 1935 Oil and Gas Journal. A discussion of the "adhesiontension" concept used by Garrison has been presented in anotherpublication, together with the reasons for the recommendation that the term"adhesion tension" be abandoned. In view of the fact that some of thedata used by Garrison have been superseded by more recent work, it seemedadvisable to call attention to this fact and present the more important datacurrently believed to be correct.

In the earlier paper, Garrison set up the equations that relate solid-oiland solid-water interfacial tensions to each other, and applied data fromBartell and Miller to these equations. However the adhesion tensionmeasurements made by Bartell and Miller involved a confusion of symbols, sothat they did not actually measure the spreading pressure. The spreadingpressure is a convenient method of indicating the amount by which the surfaceenergy of a solid surface is lowered on immersion in a liquid or vapor.

T.P. 1526