| Show I I fl TT uncle i Sam r Tells I nn ells 11 Tun Where to f T Look i for Oil Vl I I I I I i I A bulletin entitled Hints on Oil all Prospecting has been Issued by Ly the United States Statts geological Ical sUr C survey In which some somo of ot tho the ways b by which oil structures can ho he detected l are pointed cut Gut In 1 this bulletin Is the statement that the belief bollet that oil oU flows lows In rivers riv nv- ers era or streams as great submarine lakes akes Is a fallacy There are aro only a few kinds of or true surface Indications of ot petroleum and most of or them are casU easily recognized says sas the bulletin In regions where oil all has hns not been proved pro to exist either cither oil gas gaa or some flome bituminous substance that was oil Is la the only rell reliable I Indication of ot Its pr presence Oil all may mar SHOp seep from rom norn a porous bed or ooze from joints In the thc rock or It mn may Issue with water at some sonic small spring or ma may form Corm a film on pools In swamps or m b ad or In water wells veils At most such seepages seep sep seepages ages nes the tho oil escapes scap In but small quan- quan yet vet the rainbow hued film tin It It spreads on water and Its odor octor are almost ai- ai most certain to attract attention n I R. R TO SAl s 1 DOMES lOIES In some some- regions' regions salt water springs 8 water springs gypsum rock alt salt and sulphur are arc associated with oil all On tho the gulf coast or of Texas and Louisiana gypsum m or rock salt on surface or In water wells may indicate indi cute cate tho the presence of or oil ns as the oil oilfields fields of or that region ar are commonly as associated associated associated as- as with salt satt domes domes' that contain great masses of at san and gypsum These minerals however occur also In abundance abundance dance In regions where no oil titus bus been found and where It can not possibly pos PO- sibly sibl exist Many rIn things are frequently r re referred re- re erred to RB an indications of or oil which have no connection whatever with it Probably tho the most common of or these fe is IR tho rainbow colored film produced on water h by iron oxide or magnesium oxide or b by decaying decaying- animal or vegetable vege vege- table matter Tho The film can bo be distinguished from the tho film produced b by oil all for tor It has no smell of or petroleum and Is ts brittle whereas oil film Is to J tough h Rainbow films that do not In Indicate tn- tn oil will wilt break into separate patches when stirred and the patches are arC not likely to join Into one smooth sheeA sheet shee A A number nUmbe of or erroneous popular be beliefs lie- lie lIes about tho of at oil de deserve deerve de- de serve ervo particular p mention It I Is sometimes sometimes some some- times said that oil occurs below the tho surface surta c of ot the ground In some regions Just as aa water does docs In itt others other This would mean that a well In an nn pit region re- re gion Ion Is as lIkel likely to strike petroleum ns as a well vell In a water bearing region Is as likely lIkel to strike water water that that the oil Is IB distributed In an almost continuous continuous con con- sheet beneath extensive parts ct ef cf the countr country This Is not true Another statement frequently heard Is I that the oil forms orm an nn under ground round I dream and that a luck lucky location for fora a 1 w vell ll must lie over that stream Expensive and fruitless drilling has re repeatedly TO- TO pea t I l shown that streams of ot oil do not exist A belief beller that Is III strongly strong stroH ly h. held In some flome parts of ot tho the country countr In that pools aro are connected that connected that sonic channel connects the pools In an nn oil region This belief boller 13 is absolutely disproved disproved dIsproved dis dIs- proved h by tho the ranks of or ban barren en welts wells that encircle practically e cr every producing In ing oil pool In the tho world Another wrong g Idea Is that petroleum occurs occur In underground pools or lakes In fact prospectus of ot sonic some oil companies re refer re- re for fer to lakes and rivers rl o ot oil oil giving tho the Idea of great reat caverns cn filled tilted with oil Not ot a n. single such cavern erD has been found In nn any oil field In tn the United States OH Oil as 5 really reaU contained In the tn tny openings b between grains of ot sand In tho the pores pore and crevices ot or a 0 crys crystalline talline limestone or or as In tho the larger lar er wells In the comparatively small openIngs openIngs open- open Ings Inga of or a a. very porus rock Petroleum Is Is contained in time ino that underline certain parts part or of the tho country count count Most oil all Is found In beds bed of ot sand limestone or sandstone but Associated As ns is- is with these beds thero there are arc In InvarIably Invariably In- In variably shale shalo Improperly called slate by b oil men and clay cia tI n S. SANDSTONE EIn E. E In practically practical o er every producing oil region of or tho world beds of oC limestone or sandstone lie between thick beds bt cs of ot shale shalo or cla clay A region without these rocks has small email prospect of or containing commercially nc of or petroleum Certain other kinds of or orrock rock such as granite An gneiss iss schist t. t and are distinctly form oil fields and drilling In such rocks Is If a puro pure waste of or mono money and tim time Of ot course as thero are aro exceptions exceptions exceptions to all rules a few fow recorded wells ells havo struck oil below rocks such as those indicated but no paying oil field has yet ot been ben opened In such rocs In vcr ever every oil field a n. little oil is HI t so generally through the oil bearing bearing- beds that a n. well reaching reaching- these beds at almost any place Is likely lIkel to get et a showing sho such as a L rainbow colored colored col cot ored film on drilling water but oil oilIn oilin In paying quantities is found only in comparatively small pools In pools practically every even tiny tin opening In Inthe Inthe inthe the oil bearing bed Is filled with wih oil or with tho the gas that generally general accompanies accompanies accompanies ac ac- ac- ac companies it Tho Time formation of or an oil pool ap appears p p- p pears to depend on several oral thou though h other conditions that arc are not yet et clearly clearl recognized or defined 11 may account for tor tho the absence of pools where favorable reco recognized conditions are However In areas of ot sedimentary I rocks by far the tho most Important and detected h by ly a stud study of or tho the surface is Indeed the only On condition that can be bethe beI bethe the structure of oC the roCks rocks by which Is meant the wa way the they are aro folded or I titled Where the oil bearing beds are aro re rear oil oU has arched ar hed or bowed upward tho the In iii many places formed S lO-S at the tho top of ot the arches STRUCTURE The Ideal form forni of or oil bearing sand sandor or set of beds Is dome shaped like I In a n basin or a a. set of or basins bains turned upside upside upside up up- upI I side down downS but hut in man many places simple archin Is sufficient to afford other types of or structural features aro are a 1 gathering gath bath Ipes ering ening ground for tor oil al Some Somo So mo terrace on which the dip clip or or- Inclination of ot a n. bed bedIs bedIs bedis Is Interrupted Interrupt by the accumulation of oils ois such as tho the considered moderate moderate- morer moderately teI te- te I ly favorable fn for a flattening like lIko astep u a 1 step or a terrace beyond which tte tIC bed bd again slopes downward at th the origInal original onig- onig inal Inn angle angie The Tho best pla place e to prospect for tor 0 oil l lIs Is In a re region lon where It Is the vu to exist In a t place where the tho beds show structure that structure that Is Is where beds are arc bow bowed d upward Into an arch or as it Is called caled b by an anticline An n anticline may perhaps be br de detected fe- fe dc- dc by an untrained observer but butto I ho to Is very likely like to confuse tho turo turn of ot the heds with wih tho form for of ot the tho surface of or the tIme ground round and so to be LI I mislead In Ili some parts of or tho ho United I States even en a c carefully trained c geologist reolo- reolo colo- colo gist of or largo large experience ma may be bo unable to locate without dohl doing painstaking work with wih sur surveying In- In In man many re regions lons the folds that form arches archeR or domes In fn oil 01 bearIng bearInG bearing bear- bear Ing formations can not nol bo le discovered In tn InG advance o of |
