bluuebunny/crossref_metadata_2025 huggingface dataset:
Geology and Development of the Paloma Field, Kern County, California
Authors: Wood James T.
Published: June 2014

Stratigraphy, structure and closure of the Paloma field are discussed, withsome details regarding the present state of development. The Paloma anticline, a large dome modified by faults, is the largest single closed dome in thesouthern San Joaquin Valley without surface outcrop or topographic expression.It owes its discovery to geophysics. Of nine wells drilled to the Stevens sand, seven are productive. The ultimate productive area may approximate 3000 acreswhen the limits of the field are determined.

Introduction

The Paloma field derives its name from the Paloma school, 1/2 mile north ofwhat is now the center of the field.

The field is 17 miles southwest of Bakersfield, in the south central part ofthe San Joaquin Valley (Fig. I). The present developed area and its expectedextensions are in townships 31 and 32S., R.26E. It is the most southerly ofseveral fields that produce from the Stevens sand zone.

The first well to produce condensate was a joint test drilled by the WesternGulf Oil Co. and The Texas Co. near the center of sec. 3, T.32S., R.26E., wellNo. 54–3. This well was completed on Aug. 31, 1939, at a depth of 10,178 ft.The initial production was 2280 bbl. a day of condensate and 14,750,000 cu. ft.of gas (1/2-hr. gauge) through a 3/8-in. bean.

Prior to the drilling of this well, the Ohio Oil Co. discovered anddeveloped a small gas field, which embraces a part of three townships abouttheir common corner but lies chiefly in secs. 31 and 32, T.3IS., R.26E. Thefirst well was completed on July 1, 1934, at a plugged depth of 5239 ft. afterhaving been drilled to 7957 ft. Production was found in a 59-ft. zone 110 ft.below the

Fourth Mya bed, within the San Joaquin clays. Until recently this field wasknown as the Buena Vista gas field. It is now carried by the Division of Oiland Gas as the Paloma gas field. Production within the Paloma gas field isderived from six wells, producing from several different zones in the intervalfrom 4177 to 5548 feet.

T.P. 1471
Calibration and Control of the Supercentrifuge for the Fractionation of Oil-well Drilling Muds
Authors: Oliphant S.C. , Houssiere C.R. , Fancher George H.
Published: June 2014

Drilling mud can be an item of great expense on the Gulf Coast. In order tounderstand the nature of a drilling mud, it is desirable to know thecomposition and size of the mineral particles that are present. Thesupercentrifuge has been adapted to the fractionation of mud, and this paperdiscusses the calibration and methods of operation and control. An alignmentchart has been prepared, which was found useful in this work. Typical data areincluded, showing the comparative reliability of the method.

Introduction

The application of the Sharples supercentrifuge to the determination of bothparticle size and the particle-size distribution in colloidal systems has beenpresented previously. While other methods such as elutriation, the Casagrandesedimentation method, microscopy, and the ultracentrifuge are available fordetermination of the sizes of particles, the supercentrifuge has the advantagesof large capacity, rapidity of determination, simplicity of operation, and lowmaintenance and operating costs.

The Sharples supercentrifuge consists essentially of a balanced cylindersuspended from a vertical drive shaft that is driven by either air, steam, oran electric motor. The supercentrifuge and the equipment used for its operationare shown in Fig. I as set up in the laboratory.

The mud suspension to be centrifuged, usually 2 per cent or less of solidsby weight, is allowed to flow into the bottom of the hollow rotating cylinderthrough a small nozzle. From the nozzle, the suspension flows upward parallelto the wall of the bowl and out through channels that open into the bowl nearthe axis of rotation.

T.P. 1530
Factors Influencing Electrical Resistivity of Drilling Fluids
Authors: Sherborne John E. , Newton William M.
Published: June 2014

The relation between the properties of electric logs and the fluid used indrilling a well is briefly discussed in this paper, and the fact that theresistivity of the drilling mud and its filtrate can appreciably affect suchlogs is shown.

Apparatus was designed and a procedure established to determine the effectof various factors on the resistivity of drilling mud. Five muds commonlyemployed in California were tested and the following observations weremade:The effect of raising the temperature from 80?F. to 180?F. is to decreasethe resistivity of the mud or filtrate approximately 50 per cent.The resistivity of the mud in most cases closely approximates that of itsfiltrate.The change in the resistivities of muds caused by the addition of chemicalis not the same function of the amount of chemical added for each mud.The effect produced by increased sodium chloride content is to reducemarkedly the resistivity of the mud and its filtrate.Weighting materials, such as Baroid and limestone, tend to increase theresistivity of drilling mud.Cement and counteracting reagents reduce mud resistivity.

Introduction

During recent years, the practice of "electrically logging" ageologic formation by means of a system of electrodes lowered in a well borehas provided data of inestimable value concerning the nature of the sedimentspenetrated. Thus, it is generally possible, by means of electric logs, todistinguish readily the differences between shales, sandstones, cherts, limestones, and other rock forms, The distinguishing characteristics recordedin this manner have made possible long-range and closely detailed mapping andvisualization of deeply buried structures to a degree not to be obtained with areasonable expenditure of money by any other means at present in use.

Besides being of value in correlation work, electric logs have been found, in some instances, to be useful in estimating the nature of fluid containedwithin the pores of a rock. In special cases, even the relative permeabilitiesat different horizons have been determined. That electric logs should reflectin some measure such physical properties of rocks as porosity and permeabilityand, in addition, give rise to data pertaining to the fluid content of rockinterstices, becomes evident when the conditions giving rise to the electricalphenomena measured are known. However, it is not the purpose of this paper toreview the present status of electric logging; rather, the reader is referredto the papers cited on page 220 for the principles and practice involved.

T.P. 1466
An Engineering Study of the Magnolia Field in Arkansas
Authors: Winham H.F.
Published: June 2014

The history, development, subsurface geology, production, economics andestimated reserves are discussed in this paper. The Magnolia structure is ananticline with a known maximum structural relief at 372 ft., and the arealextent of the producing acreage is 4494 acres. Production is obtained from theSmackover oolitic lime and 116 successful wells have been drilled. The field, which was developed on 40-acre spacing, has been under strict control. It isbelieved to be producing with a strong water drive. To date it has producedmore than eighteen million barrels and the estimate of ultimate recovery is 220million barrels.

Early History

The Magnolia field is in Columbia County, Arkansas, T. 17 S., R. 19 and 20W. Various geologists had long been interested in this general area, and asearly as 1921, John F. Magale was able to define a surface structure.

The first wildcat, one of the first in Columbia County, was drilled in 1923by Mid-States Oil Co., in sec. 10, T. 17 S., R. 20 W. This well was about 11/2miles northwest of the Kerlyn Oil Company's discovery well and was based onsurface geological work done by Jewel and Dobie. Subsequently, several shallowwells that were not carried below the Upper Cretaceous beds were drilled in theimmediate area of the discovery well, but none of them contained any commercialshowings of oil or gas. In the latter part of 1935, Elam and Magale (orSouthwood) Garrett No. I was located in sec. 13, T. 17 S., R. 20 W., 3/4 mileeast of the discovery well. It was drilled to a total depth of 4018 ft. in thelowermost Glen Rose beds but failed to obtain any showings of oil or gas.

Interest had been stimulated in this general area, however, by the discoveryof several oil fields, mainly Glen Rose oil production in the Rodessa field inLouisiana in 1935, Smackover lime production in Snow Hill in May 1936, production from the Cotton Valley formation in Schuler in 1937, and Smackoverlime production from the Buckner field in November 1937. With this backgroundand subsequent seismic work, which was carried on partly because the oldshallow wells drilled in the township had shown evidence of closure in theUpper Cretaceous beds, the discovery well, Kerlyn Oil Company's Barnett No. I, sec. 14, T. 17 S., R. 20 W., was originally projected to a total depth of 6300ft., to test the equivalents of the Morgan sands of the Cotton Valley series, then producing at Schuler. The well was carried to a depth of 6325 ft. andtested the objective beds without finding commercial production.

T.P. 1491
Determination of Oil-well Capacities from Liquid-level Data
Authors: Rodd Charles C.
Published: June 2014

Prior to 1938, proration procedure in Kansas required the physical testingof wells in order to set up a basis for allocating production. Subsequently theuse of liquid-level data and bottom-hole pressure data was authorized oncertain types of wells as a basis for calculating well capacities, therebypermitting wells to be tested at low rates and with small volumes ofproduction.

This paper gives some attention to the equipment used for obtainingliquid-level data but in general it is devoted to the theoretical and physicalfactors involved in well testing by drawdown methods. These tests are dividedinto two classifications:liquid-level data used directly to calculatecapacitiesliquid-level data and liquid-level measuring equipment usedin connection with other data to determine bottom-hole pressure. Equations andcalculations for both types are shown.

Well capacities calculated from fill-up data have not been used generallybut offer a simple means of testing some wells. Theoretical factors andcalculations for such tests are shown.

In the state of Kansas, proration laws required that the "ability of awell to produce" be given consideration in state allocation orders and formany years this was the only factor used in prorating the allowed oil. The"ability of a well to produce" was the quantity of oil that could beobtained from a well in a prescribed period, usually 24 hr. Early in thehistory of State-regulated proration, Kansas operators realized that, unlesssome restriction were placed upon equipment, the competition between producersto obtain large well "potentials" might result in a race to install thelargest pumping equipment. Consequently, restrictions were placed upon the sizeof tubing and length of pump stroke that could be used in pumping wells duringpotential tests. Later, restrictions were placed also upon the size of tubingand chokes that could be used in flowing walls.

T.P. 1475
Reservoir Analysis and Geologic Structure
Authors: Bugbee J.M.
Published: June 2014

The engineer and the conservationist agree that effective water drive is thedesirable reservoir production mechanism. Water drive may result either fromthe expansion of edge water, the reservoir water bordering an oil pool, or fromthe artesian flow of edge water from the outcrop. Thus, the extent of thereservoir has an important bearing upon both the rate and the ultimate quantityof water influx to an oil pool.

Lens-type reservoirs are generally recognizable, but the complete structureof the more important domal types, having possible limitations from crestal andsynclinal faulting, is not well understood. The delineation from cores, electrical logs and exploitation phenomena of the crestal portions ofreservoirs is increasingly exact. This paper suggests that inference from thesefactual pictures, combined with the scattered well and geophysical data of thesynclines and with consideration of the dynamics of structural formation, maybe applied to solving the complete geologic structure. Since faulting on thedomes and in the synclines may effectively seal and thus limit the size of areservoir and bar additional water influx, consideration of geologic structureand its possible effects is essential to complete analysis and prediction ofreservoir performance.

Introduction

Implicit in reservoir studies is the fact that the oil must be displacedfrom the reservoir rock by some other fluid, either gas or water, and thisunderstanding yields the terms descriptive of the major reservoir productionmechanisms, gas expansion and water drive. Three recent papers make clear theeconomic and conservation preeminence of water drive as a production mechanism;in fact, the title of the latest of these is "Production under EffectiveWater Drive as a Standard for Conservation Practice."

There appears to be an assumption at times among analysts that theeffectiveness of a water drive is solely dependent on the rate of oilproduction; that is, if water drive appears to be insufficient or lacking, alower oil-recovery rate would increase or reveal it. This assumption mightresult from the fact that the analysis has been wholly developed during theperiod of production curtailment; that is, since 1929. The writer takes it thatthe recurrent phrase in De Golyer's paper, "some degree of waterdrive," is related to this assumption. In California, an extraordinaryphrase, "inactive water drive," is rather common and the connotation ofuncertainty regarding our knowledge of reservoir performance is evident.

T.P. 1527
Relationship between Velocity, Oil Saturation, and Flooding Efficiency
Authors: Earlougher R.C.
Published: June 2014

Based on laboratory tests conducted with the use of fresh core samples aswell as a considerable amount of field data obtained from numerous water floodsin northeastern Oklahoma, it appears that for any given oil saturation there isa critical maximum velocity above which the oil-recovery efficiency falls offvery rapidly. In effect, when a water flood is operated above this criticalvelocity, the injected water-oil ratio rises extremely fast, thus shorteningthe economic life of the flood and reducing the ultimate oil recovery. Thiscritical velocity apparently varies considerably with the percentage of oilsaturation of the sand, so that in effect the higher the oil saturation at thebeginning of a flood the higher the velocity that can be used successfully. Inreviewing several of the earlier floods in the Mid-Continent area, it isconcluded that most of the failures were due to two things:too Iowan oilsaturation, such as 30 per cent, andtoo high water-injection rates.

Although considerably more field data are necessary to establish definitelimits, it would seem that the proper field injection rate for a 330 by 330 or440 by 440-ft. spacing varies from approximately 1 bbl. per foot of sand perday where the oil saturation is as low as 30 per cent up to 5 bbl per foot ofsand per day when the oil saturation is as high as 45 to 50 per cent.

Introduction

With secondary recovery by water-flooding receiving more and more attentionthroughout the industry, a greater working knowledge of multiphase flow underfield conditions becomes more and more necessary. A great deal of research hasbeen carried on in highly idealized laboratory conditions, from which certaintrends have been indicated, but with few exceptions no direct application tofield use has been reported. Widely varying conclusions have been drawn fromthe mass of idealized laboratory experiments and often this divergenceapparently was due to the neglect of connate or interstitial water.

Since interstitial water is such an important factor in water-floodingoperations, it then follows that any laboratory flooding experiment mustnecessarily take it into account; and since it is difficult to set uplaboratory models to allow for interstitial water, the next best procedure isto use fresh core samples for such tests. Even this procedure has itsdifficulties, inasmuch as it is possible to run only one flooding test on eachsample, as each sample differs somewhat in character from all other samples.However, this disadvantage can be overcome to a large degree by the use of anextremely large number of samples.

T.P. 1592
Permeability as a Function of the Size Parameters of Unconsolidated Sand
Authors: Krumbein W.C. , Monk G.D.
Published: June 2014

The relation between permeability and the size parameters of unconsolidatedsand is approached by considering sands as logarithmic frequency distributionshaving the basic parameters mean size and standard deviation. Sieve separateswere mixed in accordance with the normal logarithmic probability law, so thatthe mean and standard deviation could be varied at will. Experiments wereconducted in which one parameter was kept fixed and the other varied; in thismanner the dependence of permeability on the individual parameters wasevaluated. It was found that permeability can be expressed as the product of apower function of the mean size and an exponential function of the standarddeviation.

Introduction

Earlier studies of the effect of size of particles on the permeability ofunconsolidated sand have shown that the permeability varies with the square ofsome average diameter. This was first pointed out by Hazen in 1892 and verifiedby Slichter in 1898. Hazen's mean size was defined as the 10 percentile of thecumulative curve (i.e., size that is smaller than 90 per cent of thedistribution and larger than 10 per cent). Slichter's effective size, on theother hand, was found by Wilsey to agree with the 31 percentile. Fair and Hatchfound that the geometric mean size of sieve separates yielded the same powerfunction; Hulbert and Feben found that the permeability of sieve separatesvaried as the 1.89 power of the median diameter (i.e., the size associated withthe 50 percentile of the cumulative curve).

Relatively few studies included the effect of the "sorting" of thesediment on the permeability. It was recognized that the nature of the sizedistribution, in terms of the spread of the particles about the mean, affectsthe permeability, but no systematic investigations of this effect are known tothe writers. Cloud demonstrated that the effect of the grain-size distributionon permeability is definitely measurable. In the present paper the authorsinvestigate this relation analytically, and show that the effects of the sizeparameters on permeability may be predicted for at least a restricted set ofconditions.

T.P. 1492
Response of a Gulf Coast Drilling Mud to Chemicals, Temperature and Heat-treatment
Authors: Fancher George , Whiting Robert L.
Published: June 2014

A typical drilling mud from the Hastings oil field, Brazoria County, Texas, containing only 8 per cent (dry basis) of material of colloidal dimensions, which is largely illite, was concentrated to a density of 10.2 lb. per gal. andused in this study. The effects of water dilution, treatment with complexpolyphosphates, temperature and the time of heating upon the rheologicalproperties of the mud were investigated. It was found that water plays animportant part in chemical treatment and that sodium acid pyrophosphate andsodium tripolyphosphate were more efficient than other complex polyphosphatesfor chemical treatment. Muds treated with either of these chemicals manifestedmaximum reduction in viscosity and minimum filtration rates at lowconcentrations. Furthermore, mud treated to minimum viscosity with either ofthese two chemicals was virtually unaffected by heat-treatment.

Introduction

The drilling of deep wells is dependent upon the use of drilling mud, andproblems frequently arise concerning the effects on mud of temperature, prolonged heating and aging. The use of chemicals to control the rheologicalproperties of mud is a well-established practice. Salts of weak organic acidssuch as sodium tannate or gallate were used at first until the complexphosphates of sodium were found to be more efficient. Consequently, it seemed important to investigate the reactionof a mud to chemical treatment with phosphates, temperature, heat-treatment andaging, particularly since previous work in the laboratory at the University ofTexas had provided the particle-size distribution and mineral composition of Hastings mud.

Properties of Mud Used in Experiments

A large sample of the mud from a drilling well in the Hastings field, Brazoria County, Texas, was obtained directly from the circulatory system. Someof the general physical characteristics of the mud and other data are presentedin Table I. The Alexander mud was used for the experimental work. Comparisonwith Curkeet mud indicates a considerably greater dilution but otherwisesuggests similarity. The mineral composition and particle-size distribution ofCurkeet mud (Table 2) are available (Fancher and Oliphant). It is suggestedthat Alexander mud would have a similar composition.

T.P. 1589
Effects of Certain Gums and Starches on Filtration of Salt-water Muds at Elevated Temperatures
Authors: Perkins Frank , Craft Benjamin C.
Published: June 2014

The wall-building properties of salt-water muds can be maintained at hightemperatures by additions of gum karaya, gum ghatti, gelatinized starch, orcommercially prepared starch. A germicide should be used to preventfermentation.

Introduction

The behavior of drilling mud has received special attention from thepetroleum industry within the past few years in numerous research projectsdealing with such subjects as chemical treatment, gelation, and filtrationcharacteristics.

The importance and control of filtration, or water loss, is readilyapparent. It affects the analysis of side-wall cores and interpretation ofelectric logs; it controls to a large extent the work of primary cementing, reduces the amount of expensive fishing, and permits the running of longstrings of casing.

It has been found that among the many factors that have an adverse effect onfiltration, the presence of electrolytes, in general, and of salt, inparticular, is outstanding. The effect is one of flocculation of the colloidsdue to neutralization of the negative charges on the clay particles. Thisreaction is further increased on the Gulf Coast because high temperaturesreduce dispersion to a minimum, causing increased flocculation in both fresh-water and saltwater muds. The problem of reducingwater loss in salt-water muds by the addition of gums and starch at atmospherictemperature has been investigated, and many successful field tests in WestTexas indicate its solution. From the work of Byck it is concluded that noexisting method will permit an approximate determination of the filtration rateat high temperatures from data taken at room temperatures. Filtration should bemeasured at the temperature actually anticipated in the well, or at least at anumber of lower temperatures and extrapolated over a small range.

A laboratory study has been made of the chemicals available for thefiltration characteristics of salt-water muds at high temperatures, and the useof germicides to prevent fermentation.

T.P. 1551
A Method for Evaluating Pressure Maintenance
Authors: van Wingen N.
Published: June 2014

This report describes one possible method of determining the economics ofpressure control and maintenance operations as applied to a deep, high-pressurereservoir having a low gas-oil ratio. The results of the analysis indicate thata premise of increased recovery need not be predicated to justify economicallysuch methods of operation. The entire problem of determining the feasibility ofpressure-maintenance operations is thus resolved into a consideration of thefollowing:a determination of increased recoveries, resulting from pressurecontrol and maintenance as against deferred sales for the gas, including aconsideration of the economic feasibility of purchasing gas for injectionpurposes;an investigation of the extent to which it will be possible tocontrol the expansion of the secondary gas cap so that no appreciableby-passing of the cycled gas will result.

Introduction

One of the most important factors involved in the selection of a method orscheme of operation for any given reservoir is the consideration of optimumeconomic returns. As wasteful operation leads to diminished profits, a greatdeal of thought has been given in the petroleum-producing industry toimprovements in the technique of developing and producing oil fields. Only inthe last decade, however, has sufficient knowledge become available for theseconsiderations to be extended effectively from the early standpoint whenimprovements of mechanical equipment were of chief concern to include theconcept of the effect of exploitation methods on the ultimate recoveryobtainable from a particular reservoir.

In this paper a description is given of one possible method of determining theeconomics of a primary recovery, or pressure-maintenance operation, as appliedto a deep, high-pressure, low-permeability reservoir. The analysis has beenmade in two parts on the following basis:That progressively higher degrees of pressure-maintenance operations willresult in correspondingly greater ultimate recoveries, which the writerbelieves actually will be true.That the oil and gas recovery will be the same as would be obtainable by thenatural depletion method of operation regardless of the degree of pressuremaintenance.

The primary intent is thus to attempt to demonstrate to what extent aconsideration of relative increased recoveries for operations under variousdegrees of pressure maintenance need be predicated in order to justifyeconomically pressure-maintenance operations.

T.P. 1665
Positive Colloid Muds for Drilling through Heaving Shale
Authors: Bond Donald C.
Published: June 2014

Positive colloid mixtures have been prepared which possess all of theproperties desirable in a drilling mud for penetrating heaving shale. Thesepositive colloid muds are stable and they can be weighted to almost any desiredspecific gravity. They can be given any viscosity or thixotropic gel strengthrequired, within reasonable limits. They have excellent filtration, orwall-sealing, properties. They are not affected by relatively hightemperatures. They cost, initially, a little more than silicate muds, but theyhave many advantages over silicate muds. They have electrical resistivitiesapproximately equal to the resistivity of shale, which is highly desirable whenthe hole is to be logged electrically. Best of all, these positive colloid mudsare true colloidal mixtures, which have no swelling or disintegrating effect onheaving shale. '

The Nature of Heaving Shale

The penetration of heaving shale formations during drilling may be inferredfrom several effects that can be noted at the surface. The mud pumps may slowdown or the circulation of mud may cease entirely. The physical properties ofthe drilling mud, such as specific gravity, viscosity, or gel strength, maychange rapidly. (These effects are not to be confused with those caused bymixing of the mud with brine or with cement.) Cavings of shale may appear inthe mud returns. Finally, the drill pipe may be seized so firmly that it cannotbe turned.

It is found that these effects are symptoms of two conditions that may exist inthe hole. In some instances, a large cavity filled with sticky, viscous shaleis formed at the bottom of the hole when the heaving shale is penetrated by thedrill. In other cases a plastic mass of swollen shale sloughs into the drillhole at some point above the drill. In either case the result is a decrease orcomplete cessation of circulation of mud, accompanied by increased resistanceto the rotation of the drill pipe.

T.P. 1674
Effect of Certain Micro-organisms on the Injection of Water into Sand
Authors: Plummer F.B. , Merkt E.E. , Power H.H. , Sawin H.J. , Tapp P.
Published: June 2014

This paper describes briefly some of the common micro-organisms that occurin waters obtained from tanks in the Luling and east Texas oil fields;discusses in some detail the effect of the organisms on the chemical content ofthe waters; describes the bioproducts and precipitates resulting from thegrowth of bacteria and algae; and illustrates by means of experiments theeffect of these organisms and their precipitates on the permeability of oilsands into which contaminated water is introduced. The experiments anddiscussion are designed with special reference to waterflooding andwater-disposal problems.

Early Work on Micro-Organisms in Oil-Field Waters

It has long been known that microorganisms are present in oil-field waters.Rogers, Bastin, Gahl and Anderson Ginsburg-Karagitscheva, Ginter, and Bushnelland Haas have pointed out their presence and possible chemical effects onoil-field waters. Sanders has found them in oil and Klinkenberg has mentionedthe possible effect of bacteria on the flow of water through sand. However, very little has been published by petroleum engineers on the quantitativeeffect of micro-organisms on the permeability of oil-field fluids or on methodsof counteracting harmful chemical effects of oil-field bacteria or on methodsof sterilizing and purifying oil-field waters on a large scale. Mostpublications on the microorganisms of springs and ponds are by biologists andwritten from a biological point of view, and they do not deal particularly withoil-field waters.

Description of Micro-Organisms

Four types of organisms are present in oil-field waters and appear to play aprincipal part in producing harmful precipitates; that is, iron bacteria, sulphur-oxidizing bacteria, sulphate-reducing bacteria, and blue-greenalgae.

The iron bacteria were discovered by Ehrenberg in 1836. Many kinds occur.One of the commonest forms in Texas waters is Gallionella. This form is longand ribbonlike or tapelike, and under the microscope it looks like evenlytwisted, tiny, spiral threads or bands (Fig. I). The spiral bands may occur assingle filaments or may be twisted together. The filaments are covered withferric hydroxide secreted by the bacterial cell (Fig. 2). The terminal cellstructure, only 1.2 by 0.5 microns in size, consists of two coccuslike cells,0.3 by 0.5 microns in size.

T.P. 1678
Natural Potentials in Sedimentary Rocks
Authors: Dickey Parke A.
Published: June 2014

Potential differences between strata of shale and sandstone have beenrecognized for about 15 years, and they form the basis of the electricallogging of oil wells. Hitherto these potentials have been ascribed solely toelectrochemical reactions caused by the disturbing effects of the water in thedrill hole through which they are generally measured. Observations by theauthor in wells empty of water and in a mine shaft suggest that potentialdifferences between sandstones and shales are natural and specific propertiesof the rocks, although they are modified in measurement by the disturbingeffects of the water in the drill hole. The cause of these potentials probablyis to be sought in the relative polar adsorptive capacities of quartz and clayparticles.

Introduction

The existence of potential differences in the surface of the earth has beenknown for some time, and their measurement has facilitated the discovery ofgeological discontinuities such as ore bodies. The technique of measurement hasbeen well established. 1–3

In measurements in oil wells, it has been found that the potential of shaleswith respect to some arbitrary reference is very nearly constant in anyonewell, at least below the zone to which meteoric water has gained access.Sandstones and some other types of sedimentary rocks have a difference ofpotential with respect to shale that is negative and may attain a value of 200millivolts or more. The difference of potential, as usually measuredcommercially with water in the hole, is distributed over about one footvertically at the top and bottom contacts of the sandstones. The sharpness ofthe curve at the formation contacts can be improved by using a short electrodethat is close to the wall of the hole.

These potentials generally have been ascribed to the disturbing effects of thewater in the drill hole. Potentials have been found, however, in wells in whichno water was present. In the course of experiments in electrical logging inPennsylvania, carried out by the Pennsylvania Geological Survey, observationswere made of several phenomena that hitherto have not been described, to theauthor's knowledge, in the published literature.

The potential differences across the contacts of sandstone and shale are calledin this paper "natural potentials," as distinguished from thepotentials caused by electroendosmosis (electrofiltration) and concentrationdifferences, which will be discussed subsequently.

Potentials in Cored Well

In the spring of 1942, the author measured the potentials in an exploratorywell (Day 13, near Grand Valley, Pa.) which had been cored with diamond tools.The potentials were first measured with fresh water in the hole. A null balancepotentiometer was used in this and all the other measurements described in thispaper.

T.P. 1625
The Interpretation of Earth-resistivity Measurements
Authors: Muskat Morris
Published: June 2014

The method of R.W. Moore for determining subsurface interfacial depths bymeans of integrated curves of apparent resistivity has been analyzedtheoretically. It is found that the only unique tangents that can be drawn tosuch curves are the asymptotes at infinite electrode spacing and the tangentsthrough the origin at vanishing electrode spacing. Explicit expressions havebeen derived for the relationship between the electrode spacing at the pointsof intersection of these tangents and the thickness of the surface strata as afunction of the conductivity parameters for the two-layer and three-layerearths. It is found that in all cases the electrode spacing at the points ofintersection will exceed 3/2 of the thickness of the surface layer, and mayeven become indefinitely large as the resistivity of the deepest layersincreases as compared with that of the surface layer. These results do notagree with the empirical findings of Moore that the intersection of the tangentlines fall at an electrode spacing very approximately equal to the thickness ofthe surface layer.

Introduction

In a recent paper, R.W. Moore proposed a new method for the analysis andinterpretation of earth-resistivity measurements. This consists essentially inplotting against the electrode separation of a Gish-Rooney system the integralof the apparent resistivity with respect to the electrode spacing, andobserving the breaks in the integral curves. Specifically, tangents are drawnto the various segments of the integral curves, which show appreciablydifferent slopes, and the intersections of these tangents are used asindications of the depths of the various underlying strata. By numerousexamples Moore has shown that the electrode separation at the firstintersection so found agrees very closely with the depth of the bottom of thesurface layer. Moreover, in a number of instances the intersections for greaterelectrode spacings seemed to correspond to the depths of deeper beds.

T.P. 1761
Viscosity of Natural Gases
Authors: Bicher Leo B. , Katz Donald L.
Published: June 2014

A correlation is presented for predicting the viscosities of light paraffinhydrocarbon mixtures such as natural gases for temperatures from 0? to 400?F. and forpressures from atmospheric to? 10,000 lb. per sq. in. The correlation is based on theviscosity data for the methane-propane system and requires only a knowledge of the molecularweight of the natural gas. The viscosities of natural gases reported in the literature up to2500 lb. were reproduced by the correlation with an average deviation of 5.8 per cent.

Introduction

The viscosity of a natural gas is required whenever calculations are made ofthe pressure drop that occurs while the gas flows through pipes or porous media. Methods ofpredicting the viscosities of gases at the present operating pressures are not available.This paper presents a simple method of predicting the viscosity of a natural gas in thesingle-phase region from its molecular weight, temperature, and pressure.

Viscosity of Methane-Propane Mixtures

The viscosity of methane, propane, and four of their binary mixtures, 2?,4?,60, and 80 mol per cent, have been determined for pressures from 400 to 5000 lb. per sq. in.and temperatures from 77? to 437?F., with an experimental accuracy of 3.2 per cent.The apparatus used in the "investigation was a modification of that employed inprevious studies on the viscosity of normal paraffin hydrocarbons. It consists of a viscosimeterof the rolling-ball, inclined-tube type, with auxiliary equipment for making up andcharging binary mixtures into the viscosimeters. The viscosity data on the methane-propanemixtures have been plotted as a function of molecular weight with lines of constant pressure, charts of constant temperature in Figs. I to 3. These charts are extrapolated attemperatures below 77?F. and at pressures above 5000 lb. per sq. inch. Prediction of Viscosityfrom Molecular

Weight of a Natural Gas

At atmospheric pressure the viscosity of light hydrbcarbon gases increased withincreased temperature, contrary to the change of viscosity of liquids with temperature.The atmospheric viscosities of the normal paraffin hydrocarbons have beendetermined by several investigators and are plotted in Fig. 4 as a function of molecular weight, with extrapolation to 896?F. and to 220 molecular weight. Data for isopentane andnormal pentane show less than 2 per cent difference in viscosity, indicating that Fig. 4 canbe used for isomeric paraffin hydrocarbons with an accuracy of approximately 2 per cent.Trautz and Sorg determined the atmospheric viscosities of methane-propane mixtures and showedthat they are proportional to the molecular weight.

T.P. 1599
Applications of the Electric Pilot to Well Completions, Acidizing, and Production Problems in the Permian Basin
Authors: Lehnhard P.J. , Cecil C.J.
Published: June 2014

The paper describes the use of the Electric Pilot in the Permian Basin formaking permeability surveys of wells and for the selective acidization ofwells. A general summary of the information obtained from the many permeabilitysurveys run in this area is given, and the possible application of thisinformation to reservoir control problems is discussed. The application of theElectric Pilot on specific wells, involving well completion, acidizing andworkover operations is also included.

Introduction

The Electric Pilot is a comparatively new tool in oil-producing areas. From thebeginning, the possibilities of this new service caught the imagination of manyof the oil operators and acidizing engineers. Through the continued and everincreasing use of the pilot during the past year, and the close cooperation ofthe oil operators who have used this service, the efficiency and utility of theElectric Pilot service has been increased to a point where it is now a wellestablished and recognized service.

There are two major uses for the Electric Pilot:permeability survey;selective acid treatments.

Permeability surveys are made to determine the thickness of the variouspermeable sections at the borehole, the vertical position of these zones at thebore hole, and the relative capacities of the various zones.

Nomenclature

Data obtained from the permeability survey are used to calculate threedifferent indexes that pertain to the volume of fluid injected into the variouspermeable zones. A nomenclature for these various indexes has been set up, which correspond with the various productivity indexes, except that they are ameasure of injected fluid rather than produced fluid. The nomenclature anddefinition of the indexes used in connection with a permeability survey by theElectric Pilot are as follows:Capacity.-The volume of water injected into an individual permeable zone, ingallons per minute.Capacity Index.-The volume of water injected into an individual permeablezone, in gallons per minute per pound per square inch differentialpressure.Specific Capacity Index.-The volume of water injected into an individualpermeable zone in gallons per minute per pound per square inch differential perfoot of thickness of the zone at the borehole.

Capacity is the most generally used index, and for planning initial acidizingprocedures and most workover jobs it is sufficient.

T.P. 1759
An Experimental Water-flood in a California Oil Field
Authors: Babson E.C. , Sherborne J.E. , Jones P.H.
Published: June 2014

A study of the Chapman zone in the Richfield field, Orange County, California, indicates that the quantity of oil recovered by present methods will be only asmall portion of the oil originally in place. Since the volume of residual oilis believed to be of large magnitude, an experimental water-flooding operationhas been initiated in order to determine whether water-flooding offers promiseas an economical method of recovering some of this residual oil. A singleinjection well was drilled between old producing wells, and a water-treatingplant using alum flocculation and chlorination was designed and built. Waterhas been injected into the input well for six months at rates in excess of 100bbl. per day. Production from one of the neighboring wells has increasedmaterially, the oil production having risen from. 7 to 30 bbl. and the waterfrom I to 40 bbl. per day.

While definite conclusions regarding the economic success of water-flooding inthe Chapman zone are not justified at this time, it has been demonstrated thatwater can be injected into the zone on a sustained basis and that this waterwill displace appreciable quantities of oil from the sand.

Introduction

As a result of an investigation of subsurface conditions in the Chapman zone ofthe Richfield field, it was concluded that ultimate oil recovery from this zonewould probably be low and that natural water encroachment was so localized asto be of little importance from a recovery stand-point. Furthermore, it wasfound that in many portions of the zone the wells were approaching anunprofitable level of production. When these data were presented to themanagement of the Union Oil Co., their reaction was that an attempt should bemade to develop methods of recovering at least a portion of the large quantityof oil remaining in this zone.

After some investigation, it was decided that water-flooding offered the mostlikely means of accomplishing this end, but reservoir conditions in the Chapmanzone differ so widely from those encountered in any of the flooding projectsdescribed in the literature that it was difficult to evaluate the probabilityof success. Despite encouraging results from laboratory tests, it was not evencertain that water would displace an appreciable volume of oil from the Chapmansand under reservoir conditions. Therefore, it was decided to initiate asmall-scale project, for two purposes: first, to determine whether water woulddisplace oil from the Chapman sand and, second, to obtain information andexperience for future operations? if water-flooding appeared to be a promisingmethod of secondary recovery.

T.P. 1816
Postwar Inventories of Crude Oil and Petroleum Products in the United States
Authors: McIntosh Albert J.
Published: June 2014

With petroleum consumption declining temporarily after V-J day, the oilindustry is urged to use this period as a kind of stopgap to rebuild itswar-depleted inventories and help cushion the effect of this decline onproducers and refiners. Higher inventories should be reestablished, sincerecent experiences have indicated that, by and large, the present inventoriesof crude oil are too low even with the tremendous current production available.The following analysis indicates that inventory levels could be built up toabout 490,000,000 bbl. by the end of 1947, an increase of about 40,000,000 bbl.over the reported stock estimated far the war's end. If at the end of the warthe military have some 20,000,000 bbl. on hand, this inventory will either beresold to the industry or certain demands that have been assumed to be met byindustry will be supplied out of these military stocks, which would leave about 20,000,000 bbl. (net) to be built up from current production. For stockrebuilding the industry could use 10,000,000 bbl. of crude plus 10,000,000 bbl.of products, totaling 20,000,000 bbl. If this were spread over a year, thiswould mean 55,000 bbl. a day. By analyzing the average inventories held in ayear with the total quantity of goods handled during the year, the followingstudy and tables indicate how far the inventories should increase in theimmediate postwar period.

Introduction

For the period immediately following V-J day, most of the petroleumeconomists have forecast a considerable decline in the total consumption ofpetroleum and its products in the United States. This will be caused by theelimination of most of the military demands and the inability of civilians toimmediately replace automobiles, burners, etc., and thus increase theirrequirements to make up for the military decline. When the automobile industryhas been back on full production for two or three years, civilians will be ableto consume much larger quantities of gasoline. Delay in the manufacture of newoil burners and the time it takes to construct new homes, adds up to the samestory for distillate fuels. In reviewing this outlook, the question has arisenwhether the petroleum industry should not use this period of lower consumptionas a kind of stopgap to rebuild its war-depleted inventories and help cushionthe effect on producers and refiners of this sudden drop in requirements. Somepersons have indicated that hundreds of thousands of barrels a day could beused for this purpose extending over a year or more. Refineries will be inexistence, which could run over 5,000,000 bbl. of crude oil a day and crude-oilproduction might be running 600,000 to 700,000 bbl. a day above the demands nowforecast for the period after V-J day.

T.P. 1870