bluuebunny/crossref_metadata_2025_split huggingface dataset:
Underground Surveys of Oil Wells
Authors: Anderson Alexander 
Published: June 2014

In many oil fields a great variation in the production of adjoining wellshas long been observed, and a certain proportion of dry holes, situated betweenprolific producers, has been regarded as normal without thorough investigationas to cause. Similarly, an occasional prolific producer has been found in apart of a field where all other holes have proven disappointing.
Adjoining wells which showed an unreasonable difference in production havebeen surveyed, and the bottom of the poorest producer has been found to havelost sufficient vertical depth, through its drift, to diminish seriously itspenetration in the oil zone. Again, the bottom of the good producer has beenfound to be more favorably situated by its migration up structure.
Surveying of wells in California fields has shown many instances where thedry hole has drifted far off the structure to such a degree that no amount ofdeepening could ever convert it into an oil well. In other cases, edge wellshave been found to drift into the field.
At this time, in California, the surveying of oil wells is beginning to beaccepted as a routine part of operating procedure. Some operators are surveyingall of their new wells and, in some of the recently discovered fields, thispractice is providing invaluable assistance in methodical development.
The information that has been obtained from the surveying of many wells hasconvinced most operators that it pays to give careful attention to the drillingof wells. Crews are now usually cautioned to avoid reckless competition witheach other. Whereas, formerly, certain companies demanded a large footage fromtheir drillers, they now issue orders that a very moderate speed in drillingshall be maintained and that every care be taken to avoid practices likely tocause excessive deviation of the hole from vertical. As a result of these newinstructions to drilling crews, a distinct decline in the average drift of thewells drilled by these operators has taken place and fewer dry holes are beingdrilled from good locations.
Pressure Control of Oil Wells
Authors: Griswold E.H. , Wilkins W.J. 
Published: June 2014

Pressure control of oil wells may be defined as the adjustment of pressures within a well to obtain the most efficient and economic utilization of the natural gas energy with a minimum of sand troubles or irregular water encroachment. The purpose of this paper is to present the methods used by the writers in applying pressure control and a discussion of the various effects occurring within the wells affected. The benefits to be derived from the conservation of natural gas energy have been so adequately discussed and demonstrated in prior papers by various engineers that the effects on ultimate production will not be discussed other than to mention a few representative cases. The detrimental effects of irregular edge-water encroachment and of sanding up are of general knowledge to the industry.

Effect on Ultimate Production
One of the strongest objections voiced against pressure control is that of the danger or inadvisability of deferring oil production by cutting the rate of production. It has been our experience that such deferred production is returned within a few weeks or months rather than years and that an increased cumulative oil production is obtained in the early life of the well by conserving the natural energy. In many cases the rate of production is increased rather than decreased by the adjustment of pressures to obtain the minimum gas factor.
Fig. 1 shows the history of a Wilcox sand well in northern Oklahoma, which was pressure-controlled from completion. It is noted that during the early months while flowing naturally through the casing the gas factor was decreased rather than allowed to follow its natural tendency to increase. A string of 2 1/2-in. tubing was run to restrict the flow and resulted in a decreased gas factor with a more sustained rate of production. When first placed on gas-lift the gas factor again tended to increase, but after the proper pressure adjustments were made, remained approximately steady. It was necessary to defer 100 bbl. per day of oil production in order to maintain this low gas factor.
Measurements of Original Pressure, Temperature and Gas-oil Ratio in Oil Sands
Authors: Sclater K.C. , Stephenson B.R. 
Published: June 2014

Recent progress in oil-recovery methods has brought into prominencegas-energy relations in oil sands. The greater the effort made to utilize thisgas-energy relationship to the best advantage in oil recovery, the greaterbecomes the need for more precise information concerning physical conditions asthey actually exist in an oil well.
The intelligent use of gas-oil ratios when considering production efficiencyhas been the subject of much recent discussion. It has been stressed that thepressure as well as the volume of gas must be known when considering theefficiency of a producing well on an energy basis. When methods of productionare compared on an energy basis it implies a knowledge of pressure, temperatureand physical properties of the fluids at the bottom of the well.
In questions concerning gas-lift and the pressure control of wells usuallythere is a wide variance of opinion among engineers when energy relations comeup for discussion. Perhaps this difference of opinion can be traced toerroneous assumptions made with regard to the physical conditions existingwithin the well. If erroneous assumptions are made it follows that computationsbased on these assumptions will give results which also will be in error.
That erroneous assumptions are made is not to be wondered at because whenhandling a fluid composed of gas and oil, we are dealing with a complexity ofhydrocarbon components each varying to some degree in physical and chemicalproperties. This means that the physical state of the gas and oil will dependnot only on temperature and pressure but that it will be influenced also by therelative amounts of the various hydrocarbon components present. If water ispresent the problem becomes still more complicated.
From these considerations alone it would appear that we can well afford togive some thought to devising more positive methods or means for obtaining dataon physical conditions within the well rather than depend entirely oncomputations from casinghead data.
Back-pressure Control of Flowing Wells
Authors: Miller H.C. 
Published: June 2014

The energy stored in the compressed natural gas absorbed in or otherwiseassociated with the oil in reservoir sands is usually the most important factorin oil recovery. It is recognized that hydrostatic pressure and gravity may aidmaterially in the drainage of oil, but in the early life of the majority offields the principal source of propulsive energy is the expansive force of thegas associated with the oil. Since gas is admittedly the most important factorin the production of oil, its control so as to produce the maximum amount ofoil with the minimum amount of gas will be reflected in increased oil recoveryfrom reservoir sands. Controlling the gas means regulating its expansion sothat the velocity of flow of oil through the channels in the reservoir sands isneither so great that frictional resistance becomes excessive nor so slow thatthe gas, because it can travel more rapidly than oil through the irregularpassageways in the sands, will by-pass and reach the well without doing usefulwork in bringing oil from the sands.
Oil and gas flow from the reservoir sands to the well because of differencesin pressure. The rate of flow is dependent upon the differential pressuresexisting in the sands and in the well. By altering the amount of back-pressuremaintained on the well this differential pressure can be regulated and changedfrom a maximum (well flowing "wide open") to a minimum when there willbe no flow. Oil and gas flow through the irregular channels in reservoir sandsat different rates mainly because of the fact that one is a liquid and theother a gas. Therefore, because oil and gas have different characteristics offlow, application of back-pressure changes the rates of flow with relation toone another so that wide variations in gas-oil ratios are possible. Obviously, the formation gas energy will be utilized most efficiently when a unit of gasdelivers the maximum amount of oil to the well.
Analyses of Waters of the Salt Creek Field Applied to Underground Problems
Authors: Ross J.S. , Swedenborg E.A. 
Published: June 2014

Oil-field waters enter into many underground problems with which thepetroleum engineer has to deal. Whether the problem is one of infiltration ornatural encroachment, it is always desirable to determine the source of thewater before commencing repair or remedial work. The usual mechanical tests fordetermining the source of extraneous water in wells are slow and expensive. Anexcellent means for the identification of oil-field waters may be afforded bytheir chemical characteristics when the chemical character of waters from thevarious sands has been established by careful sampling and analysis cautiouslyinterpreted.
In the Salt Creek field, Wyoming, a fairly high degree of efficiency hasbeen attained in the control of field operations by utilizing the informationafforded by the analysis. All of the operating companies appreciate this meansof identifying waters, with the result that water-sampling has become generalpractice. Most of the chemical work dealing with Salt Creek waters has beendone since the laboratories of the Midwest Refining Co. and the U. S.Geological Survey, were established in the field; the former in 1922, thelatter in 1924. A spirit of cooperation has existed between the company and thegovernment personnel by which many of the data for this paper were madeavailable.

Sands of the Salt Creek Field
The principal sand horizons in the Salt Creek field are the Shannon, First, Second, and Third Wall Creeks, Dakota, Lakota, Sundance and Tensleep. Of thesethe important oil producers are the First Wall Creek, Second Wall Creek, Lakotaand the Sundance. The Third Wall Creek is lenticular and is productive in onlya few wells in the southern end of the field. There are also a number of shalewells, but they do not produce water in any appreciable amount.
Oil Recovery Investigations of the Petroleum Experiment Station of the U. S. Bureau of Mines
Authors: Mills R. Van A. , Chalmers Joseph , Desmond J.S. 
Published: June 2014

Problems Being Studied
The selection of the first problems to be studied was based largely upon thefollowing very practical questions asked by several of the largest operators inthe Mid-Continent field.What are the causes for the formation of excessive amounts of bad thick oilon properties that are being repressured with compressed air and how can thistrouble be prevented?Why, in some areas, does the oxygen in the air injected into an oil sandduring repressuring operations apparently change to carbon dioxide? Is carbondioxide formed by the oxidation of some of the oil in the sand? How can theformation of inert or low B.t.u. casinghead gas, loaded with nitrogen, carbondioxide and oxygen, be prevented?What percentage of the oil originally present in an oil sand can berecovered by the ordinary methods of operation when the gas originallydissolved in the oil is the main propulsive agent?What percentage of the amount of oil produced by ordinary methods can berecovered under average conditions by repressuring a so-called depleted oilsand?What are the relative propulsive efficiencies of compressed air and naturalgas in repressuring operations?What are the practical advantages of pressure maintenance and earlyrepressuring as compared with late repressuring?
Mathematical Development of the Theory of Flowing Oil Wells
Authors: Versluys J. 
Published: June 2014

When a well strikes an oil-bearing layer, the oil has a pressure which isgenerally sufficient to enable it to rise to near the surface (sometimes abovethe surface). As soon as a well begins to produce, however, the liquid movesthrough the pores of the reservoir bed and the pressure in the well becomesmuch lower than the pressure originally prevailing there. At some distance fromthe well, however, the pressure in the reservoir bed remains unaltered; thusthe pressure of the oil has not only to lift the oil, but also to overcome thefriction resistance in the pores. The fact that so many oil wells are gushersis a consequence of the energy accumulated in the gas.
In gushing the well acts as a gas-lift. A mixture of liquid and gas (the latterpartly dissolved in the former) rises vertically from the oil-bearing layerthrough a cylindrical casing to the surface. In time conditions alter and thewell ceases to gush regularly, then the gushing can be further promoted byinserting a narrower tube in the well and connecting the top of the oil stringto the tubing. If the action in time becomes irregular, the gushing can be keptup for a further period by forcing gas between the two tubes. In the oil fieldsthe term" gas-lift" is used actually only where extraneous gas isapplied, as in the last of the stages mentioned. The action, however, is justthe same whether the gas exclusively originates from the formation, or ispartly applied artificially. Thus by gas-lift we simply mean a vertical tube inwhich the energy of gas under pressure, and of dissolved gas, is utilized forraising a liquid.
In gushing oil wells the pressure is frequently very high and the absorptioncoefficient 0.4 (expressed in vol. ratio) of the coexisting gas is notparticularly high, so that in reality it should be assumed that a considerableportion of the gas, at any rate at the bottom of the gas-lift, is dissolved inthe oil. For water-producing wells this is not usually of such importance.
Modern Practice in Water-flooding of Oil Sands in the Bradford and Allegany Fields
Authors: Torrey Paul D. 
Published: June 2014

The water-flooding of oil sands has been widely practiced for many years inthe Bradford and Allegany fields. Its effect upon the production of thesefields has been almost phenomenal. In 1907 their estimated production was 3500bbl. per day; in December, 1929, the combined production is estimated at 33,000bbl. per day, an increase of almost 1000 per cent. in 22 years. This increasein production is directly attributable to the successful application ofwater-flooding, which has transformed the fields that were rapidly approachingabandonment into one of the most actively operated regions associated with thepetroleum industry, and has made them important factors in the production ofPennsylvania Grade crude oil.
The writer is indebted to many companies for information included in thispaper. He is particularly grateful to the Sloan and Zook Co., the PetroleumReclamation Co., George Bovaird, Jr., and the Associated Producers Co., ofBradford, Pa., who have generously made available much valuable data. Owing tothe frequently competitive and confidential nature of property purchases, ithas not always been possible to make specific reference to individual wells orproperties; but wherever feasible, specific references have been made.

Economic Factors
The successful application of water-flooding for increasing the recovery of oilhas been almost confined to the Bradford and Allegany fields. This has been duenot only to legal restrictions in other fields and to very favorable sandconditions in the Bradford-Allegany region, but also to certain economicfactors which are worthy of consideration.
There has been some alarm regarding the effects of the rapidly increasingproduction upon the oil market but the writer is inclined to believe thatfuture development can be made sufficiently flexible to meet the demand forthis grade of oil. There has been a decided tendency toward consolidation ofproperties by mergers and purchases and, in addition many of the individualproducers are content to take advantage of floods advancing on their holdingsfrom adjoining properties without developing their own on an intensivescale.
Mechanics of a California Production Curve
Authors: Herold Stanley C. 
Published: June 2014

Only two years ago there appeared in our technical magazines articleswherein it was shown that the application of back-pressure increased theultimate production of a well, that edge water can be stopped in itsencroachment by the injection of gas into the productive formation, with theconsequent conservation of energy within the pool, that gas is the source ofall energy involved in oil production, and that each pool has a definiteminimum-valued gas-oil ratio to be attained for the most economical operationof wells. Today we are not so certain of these matters. Probably in somefields, under special circumstances, these ideas are correct, but certainlythey must not be correct in all fields, under any and all circumstances. Thenature of the productive structure, the location of particular properties onthe structure, the existence of adjoining neighbors, whether these are higheror lower on the structure, and the methods of production followed by alloperators on the structure, sand for sand on depth, make these subjects worthyof full consideration.
Our difficulties in analyzing and comparing the performance of reservoirs invarious parts of the world do not rest solely upon structural features andproperty lines. We do not complete the list of causes for these difficulties ifwe add lithologic features and correlation of strata encountered by the drill, with the magnitude of pressures exerted by fluids within any of these strata. Afurther cause, one which the author believes will complete the list, is oneinvolving the theoretical mechanics of fluids within porous formations-porousin the nature of interstices in sandstones and some limestones, networks offractures in shales, and cavities in otherwise compact limestones.
The confusion of ideas concerning reservoir mechanics still with us today seemslargely due to our failure to recognize among all wells three great divisionsof theoretical mechanics, three great systems which are distinct in themselves, and according to which each well, or better, each group of wells, must beanalyzed separately. These systems have been named by the writer HydraulicControl, Volumetric Control and Capillary Control, respectively.
Superhard Metals for Tool Facing
Authors: Morgan Harry J. 
Published: June 2014

Abstract
One of the greatest improvements in drilling equipment has been the developmentof hard facing metals which are welded by electricity or by acetylene to form afacing which protects the steel of the bit from abrasive wear. The maindesirable characteristics of hard facing metals are resistance to abrasivewear, resistance to shock and perfect bond with underlying metal.
Resistance to abrasion offered by various metals shows many anomalies. Compounds containing carbon, silicon and boron are the most important hardsubstances. Carbon, as diamond, silicon carbide and especially the carbides ofiron, chromium and tungsten are the outstanding hard products in common use.Tungsten carbide is probably the most commonly used. It is made in the electricfurnace and it is important to get the right amount of carbon and the correctcrystalline structure in order to obtain the greatest hardness and greatestresistance to abrasion. It may be obtained in three main divisions: wrought, cast and casehardened.
Insert hard metals are common. The method of application varies, but it isgenerally welded to the bit, placed in channels or in drilled holes and coveredwith a hard surfacing metal. Robinson has given a very complete article on the use of inserts. Gregg and Kiittner has discussed themetallography of tungsten carbides and given a good bibliography of thesubject.
The time and expense of large-scale testing, together with variations inresults, led to the development of a laboratory testing machine for determiningthe abrasive-resisting qualities of different metals.
Law of Flow for the Passage of a Gas-free Liquid through a Spherical-grain Sand
Authors: Schriever William 
Published: June 2014

Law of Flow for the Passage of a Gas-free Liquid through a Spherical-grainSand
The flow of a gas-free liquid through a spherical-grain sand has beeninvestigated by Slichter. By theoretical considerations involving a ratherlarge number of approximations he arrives at the following flow-formula:

v = CPd2At

NLB(1-m)
where V is the volume of liquid delivered in time t through a cylindricalcolumn of sand of length L and cross-sectional area A by a pressure-drop P whenthe sand grains of diameter d are packed to a porosity m and the coefficient ofviscosity of the liquid is n. C and B are constants which were determined fromgeometrical relations; B was in reality a function of m. Values of B(l - m) forvarious values of m were given in a table.
In the same Annual Report of the U. S. Geological Survey, King reported theresults of his experiments on the flow of water through porous media. He foundthat there was a departure of about 86 per cent. from a linear relationshipbetween rate of flow and pressure, for a specimen of Dunnville sandstone forpressure drops not exceeding 60 cm. of mercury. The specimen was approximately4 cm. in diameter and 5.1 cm. in length. Over the same range of pressure hefound a departure of 45 per cent. for a specimen of Madison sandstone. Forunconsolidated sands he found departures as great as 49 per cent. for pressuredrops of 70 cm. of mercury; for pressure drops not exceeding a few inches ofwater he obtained a close approximation to a linear relation.
*This paper contains results obtained in an investigation on The Effect ofNatural Gas upon the Viscosity, Surface Tension, Adhesion and GeneralExtractability of Petroleum of Various Types, listed as Project No. 33 ofAmerican Petroleum Institute Research. Financial assistance in this work hasbeen received from a research fund of the American Petroleum Institute donatedby John D. Rockefeller. This fund is being administered by the Institute withthe cooperation of the Central Petroleum Committee of the National ResearchCouncil. Prof. H. C. George is Director of Project No. 33.
Cementing Problem on the Gulf Coast
Authors: Wilde H.D. 
Published: June 2014

At the Sugarland and Raccoon Bend fields in the Gulf Coast area, all wellsare drilled with rotary tools and the casing is always set in cement that isplaced by the circulation method. After the cement is set, the rotary mud thatfills the hole is not withdrawn or bailed out; consequently, it is notcustomary to give the cementing job a direct test either by putting pressure onthe hole to see whether the cement will hold or by observing whether aneffective water shut-off is secured.
About three years ago, this company started the practice of coring the cementleft in the bottom of the casing and examining the core thus secured. If thecore was hard and strong, the cementing job was judged a success but if thecore was incoherent, soft, and crumbly, the job was considered a failure. Ofcourse, there were intermediate types of cores and it was not always a simplematter from this examination to decide whether the job was a success orfailure. After about two years, a summary of the core examinations that hadbeen made indicated that of cementing jobs made at depths of 1000 ft. or less,60 per cent. were failures; of those between 1000 and 2000 ft., 80 per cent.were failures, and of those between 3000 to 6200 ft., 100 per cent. werefailures. This startling table emphasized the need of the study of theconditions under which the wells were cemented and of adopting means to reducethe percentage of failures.
In addition to these core tests, two wells gave direct evidence that thecementing jobs were not always successful. In one, a four-year-old well atGoose Creek, the casing was perforated, and when fluid was circulated some ofthe old cement was brought to the surface. Most of it was powdery and the fewchunks that were brought up were soft and crumbly. The other was a well at Raccoon Bend which during a blow-out brought a number of chalky, soft andcrumbly pieces of cement to the surface.