Show prospecting for oil and gas in the quest of that world sought fluid petroleum probably thirty million dollars is spent yearly in the united states in drilling operations which result only in dry holes in the ground round states the bureau of mines which has just 1 3 completed a b general study I 1 of methods of prospecting for oil and gas in a period of two years dry holes were drilled in this country at an average avera b e cost of at least per hole california and new york show the lowest percentage b of dry holes of all the oil producing states texas shows the highest percentage b of dry holes undoubtedly because of wildcat drillen drilling b oil and gas 6 as have been found in at least twenty three states and alaska petroleum Petrol euni is rarely free from sulphur but the quantity present is usually very small sulphur is abundant in the saline dome areas of louisiana and texas and may be considered to be an indirect indicator of oil and gas in popular opinion the presence of fossil sea shells in rocks is a sign of oil or gas probably because engineers and geologists when examining lands for oil nearly always in inquire of the residents if they know of any fossil shell outcrops except that they indicate the presence of sedimentary strata which is necessary for oil accumulation fossils are not an indicator in prospecting for oil and gas the chemical composition of the waters found in drilling may furnish important clues to the proximity of oil and gas approximately of the oil wells completed in the united states during 1914 1918 were drilled by the cable tool system in which formations are broken and the hole is made by the pounding of a heavy bit the three deepest wells in the united states two of these the deepest in the world were drilled with cable tools these are the lake well 8 miles southeast of fairmont W va depth feet the goff well 8 miles northeast of clarks burg W va depth feet and the geary well 20 miles southeast of pittsburgh pa depth feet the bureau of mines considers that the responsibility for many dry holes may be laid to the use of instruments such as the forked stick electric boxes bokes and other variations of the divining rod idea in the determination of drilling locations cat ions oil operators are advised to spend no money for the services of a water witch or for the use or purchase of any machinery or instrument devised for locating underground der ground oil deposits the commercial development of petroleum and natural gas fields has reached its present status within sixty years and is still considered by some operators to be per cent wildcatting declares the bureau A tendency to drill for gusher production the production that yields big returns in spite of any mechanical defects in drilling methods has frequently caused drillers drillars dr illers to pass by oil bearing strata of comparatively small yield and actually to overlook rich oil zones in proved fields in addition whole fields have been ruined by water because development methods were never carried beyond a hole in the ground stage unfortunately the petroleum industry has no mine dumps or tailing piles as at metal mines to yield fortunes through later and better methods of treatment the wasted oil and gas are gone as are the time money and effort wasted in ill advised or haphazard drilling probably as production costs increase less oil will be wasted but the need to develop and produce from sands of low yield will become more urgent with the increase in iii consumption of oil and the decrease in supply oil and gas are usually found in sedimentary rocks limestone sandstone ar or shale which differ greatly in min min era logic composition As a reservoir rock limestone usually holds the oil in crevices or small cavities or in porous sandy parts many oil men believe that production from limestone reservoirs declines rapidly sandstone is the most common reservoir for oil and gas as in the states of new york ohio pennsylvania and west vir virinia virginia inia and is common in many other states the productive sandstone strata have been given iven distinctive names many of which are firmly established over areas of thousands of square miles oil fields in louisiana texas and california furnish examples of sand reservoirs indicators are those rocks or minerals that may be or are considered indicators or signs of oil or gas they may outcrop or be found in drill holes at considerable depth indicators include asphaltum some gases sulphur salt coal and waters having a certain mineral content gases that indicate petroleum the most common gases that arise from the earth in gas cras blows and springs and which may le be deemed correctly or not as signs of oil or other hydrocarbons are petroleum gas marsh gas hydrogen sulphide gas carbonic acid gas and air petroleum gas the natural gas of commerce is the bureau of mines considers the only reliable indicator of the group A seepage of natural gas may lead to the discovery of a gas field or a pool of oil and gas gas blows are not as easily seen as oil seepages see pages and are therefore e often ofte n overlooked in the search for surface signs b A definite showing of natural gas in a drilling we well ll 11 encourages further prospecting but small tools have been blown out of a hole by marsh gas which Js is not a sign of the proximity of oil in prospecting 6 for oil the theory that gas comes from oil is not reliable without corroborating evidence fields yielding no oil produce gas in large volume the monroe gas field of louisiana the largest gas field in the united states has produced no oil altho although although uh 6 the 6 gasoline asoline content of the gas is gallons to a million cubic feet in other fields gas is found in a reservoir separate from the oil frequently as in parts of the midway field california the gas occurs at different depths over a given area and efforts to correlate these gas sands in well cross sections are fruitless again a sand may yield oil and gas in one part of a field and give gas only in another part however a gas well may lead to further prospecting and the development of producing oil wells marsh and poisonous gases marsh gas is not associated with deposits but is found most often in areas where masses of veleta vegetation have been buried under tinder sediments in steams lakes or marshes and have decayed with ai air r excluded it burns as freely as natural gas As marsh gas has no relation to accumulations of oil it does not indicate the existence of petroleum at equal or greater depths hydrogen sulphide gas is a colorless gas with characteristic act odor very poisonous one part in being fatal to mammals this gas is commonly if not universally present where oil is associated with salt domes the gas in the oil rock of the spindle top field texas is poisonous enormous flows of this gas have come I 1 from many sa salt I 1 t do dorne ni e wells A flow of cubi cubic f feet t daily came from froin 7 I 1 3 I 1 wem wells in the bryan heights do dome in e texas carbonic acid gas sometimes called damp or choke damp is heavier than air it escapes from the ground in many places bubbles up in some mineral springs and may show as bubbles in the rotary ditch or the bailed baided fluid it will not burn nor support combustion and will put out a candle flame in a confined space it is in no way related to the occurrence of hydrocarbons bubbles of air rising to the surface of a spring or pond are sometimes thought b to be natural Z gas all b ground water contains air which ma may y escape as bubbles in consequence of higher temperature or lower pressure oil and gas indications the so called paraffin or sour dirt of the gulf coast country is a yellow waxy substance resembling paraffin or beeswax it is popularly deemed an unfailing indication of the proximity of an oil and gas reservoir and is is supposed to be the result of natural gas emanations the presence of ammonia in a formation penetrated by the drill may in a way be an all indicator of the presence of oil or gas in a drilling well petroleum may be found in any quantity from a whirling iridescent film on the water in the ditch to a sudden and perhaps unexpected gusher flow but all showings of oil are not necessarily signs of oil grease from tool joints can easily be mistaken for a sign b of oil and holes in the ground have been salted with oil failure to find oil is not conclusive proof of its nonexistence unless the presumably favorable reservoir has been thoroughly tested strata containing b asphaltum or tar are found in the hi hiher higher b her levels of man many y wells during drilling b and may be a sign of oil and gas at greater depth the areal intimacy between known coal deposits and oil and gas pools in the united states may be superficially explained as a coincidence of ceolo geologic ic segregation coal can occur together with oil or gas as especially the latter only under certain limited conditions in sedimentary rocks nowhere can the development of salt in a drilling well be considered as an indicator of the existence of petroleum except in the salines of louisiana and texas where salt domes or plugs form the cores about which oil has accumulated salt is an indi actor of a favorable structural condition but not a sign of oil |