Show r Oil an and Oil Shale Lands Of Colorado rs an and Utah I J Region That Gives Promise of Substantial Results in Production Production Production Pro Pro- of Petroleum Petroleum Apparently Apparently No Connection Between Shale Deposits and Oil Pools Glen M. M Ruby In Mineral Age For several years the possibilities of ot oil oU from the shale beds of ot Northwestern Northwestern Northwestern North North- western Colorado and Northeastern Utah have gradually eclipsed the In Interest interest interest in- in terest in petroleum in that section which was caused by the discovery of the Rangeley field In Rio Blanco county Colorado About the time Wyoming began to demonstrate the value of oil oU in the Rocky 1 Mountain Mountain Moun Moun- tain section and turned the Interest of prospectors in that direction Colorado Colorado Colorado Colo Colo- rado and Utah were being examined for beds of oil oU shale and the location location location loca loca- tion and prospecting of these shale deposits caused this region to be regarded regarded regarded re re- re- re as valuable only for oil oU shale It has been generally accepted as asa asa asa a fact that the formations of the Rocky Mountain region are not oil oU bearing The sediments of this age are in la most part of freshwater freshwater fresh freshwater water origin and not favorable to the formation of petroleum but the Green river formation of age shows much evidence of maine deposition It is the Green river formation formation formation for for- mation in which the oil oU are found and which also promises to be bea a large producer of petroleum where proper structural conditions exist The petroleum In t the e Green river formation exists entirely separate from from the oil oU shale however and appears appears appears ap ap- ap- ap pears to have no connection connection with it ft The oil in the oil oU does not exist exist as free oil oU after atter the nature of ofa a saturated sand and cannot be extracted extracted ex ex- by a solvent but must be retorted retorted re ra- tort d The of the heat within with within with with- In in the retort is necessary to the completion completion com com- o of oj the ch the chemical ical action in the elements in the shale In order to form and extract the oils Additional that oil 11 shale is not likely to be the source of free oil oU in sands under a structure Is that the sandstones found in direct contact with the richest shale beds show no ev evidence dence whatever of migration migration migration migra migra- tion of oil into the sand from the I shale shaler When this peculiarity of oil I shale became generally known it if was taken for granted that the Green river formation would not be a producer producer producer pro pro- ducer ducer of petroleum and consequently it has bas not been as such I Recent studies have shown the presence of petroleum in this formation formation forma- forma tion Uon tion in certain section where conditions condItions conditions condi condI- of deposition were favorable Oil shale also is found but has has' no noco co connection whatever with the petroleum petroleum petroleum petro petro- leum leum being deposited under differ differ- ent conditions and several hundred feet above the sediments In which the petroleum was found Thus ItIs it itis itis is evident that the oil shale in the been river nver formation has no bearing bearing bearing bear bear- ing on the petroleum possibilities but since this has not been previously previous prevIous- ly recognized it has resulted in the entire formation bel being g condemned as asa asa asa a possible petroleum pr producer ducer During the recent in investigation of the Uintah basin of Northeastern Utah and Northwestern Colorado the writer discovered geologic evi evl- evidence deuce dence ence of certain conditions of deposition deposition deposition tion of the sediments in the lower part of the Green river formation which appeared to be be very favorable I to the formation of oil oU A careful search over some of these areas re resulted resulted resulted re- re in the the finding if of f several sands saturated with oil of base lInse One of the sands was over forty feet thick and a few luelle's b back ck lr from m the outcrop showed supEr super tion The oil bearing sands allds are inter inter- bedded in a n heavy body of soft sofi dark sha shale e which shows shows' none none of the he chill char chai- of the so-called so ol on 01 shale occurring several hundred feet teet higher high high- er In the geologic section While there is IS' no areal connection between this oil bearing portion of the Green river formation and the oil bearing formation of California they are pf of the same age and were e deposited under very similar although In separate seas ItIs It Itis Itis is not probable that the oil-bearing oil sands Bands of the Green river formation are as a's extensive as the oil shale deposits deposits de de- posits and they cannot be expected to cover the area r represented presented by the the California fields Th There re are areas of Green river formation in which no signs of petroleum have been r I found and further investigation will undoubtedly show that It exists In small areas compared to that covered covered covered cover cover- ed by the oil shale and in definite re relation relation relation re- re lation to the source of the s sediments The only region known to the writer In which the lower part of this formation carries oil Is s within the Uintah basin and contiguous areas and although barren in many other localities it is probable that other districts will be found where oil may be expected although not showing evidence at the surface The oil oU of the Rangeley field In Northwestern Colorado is found below below below be- be be be- low the Mesa Verde sandstones Inthe in inthe inthe the upper part of ot the Mancos shale and Is the most valuable oil of the region While no sands exist in the portion of the shale body in which the oil is found it is probable that thi horizon maybe correlated with the Ferrn n sandstone found the south southsIde southside southside side of the Book cliffs clias It Is known that this sandstone rises toward the Mesa Verde as the outcrop is followed follow follow- ed eastward and that north of Grand Junction it has changed completely to shale The territory between Grand Junction and Helper I Utah and north of the Book cliffs cUfIs contains sufficient sand to act as a reservoir that a good field may be expected in the upper Mancos under proper structure At least two such structures s have been found and will be drilled this year but as only a small portion of ot the favorable area has been searched for for- folding it is probable that more drilling sites S will be b located located Bated Bat Bat- ed and prospected The Mesa Verde formation of y Cretaceous f age was found to contain contain con con- tain several heavy sand showing s saturation saturation sat sat- t- t with oil and this may also prove to be a large reservoir reservoir reservoir reser reser- voir of petroleum The Book cliffs lJ s north of the Denver 8 Rio Grande railroad are capped by the the Mesa Mesa Verde sandstones and offers a large barge area for prospecting t In the territory around Price the Ferron sands are near the base of the Mancos and will be tested in the near future at the town of Huntington Hunting- Hunting ton twenty miles south of Price Here the Ohio Oil company is preparing preparIng preparing pre pre- paring to drill 1800 feet to test the Ferron sandstone under favorable structural conditions A As the sand In Inthis inthis this territory occupies a position similar to the Wall creek sands of Wyoming the chances of obtaining a high grade oil are very good The uplift known as the San Rafael swell exposes rocks as old aa U Pennsylvania and is flanked by the massive La Plata sandstones of Jurassic Jurassic Jurassic Ju Ju- Ju- Ju age This sandstone s series la is lamade made up of two massive sands each feet thick and separated by feet of sandy shale Although It Isa Is 18 Isa a fresh water deposit It shows much evidence of having been oil bearing before erosion exposed it In the San Rafael uplift The Immense faults west of Castle valley were probably responsible for oil from a lower horizon horizon horizon hori hori- zon coming into the La Plata sands I Since there arc are oil seeps in these i sands on the west side of the swell It Itis t a ais is presumed that any favorable folding folding fold- fold ing where the sand Is well covered east east of the major faults should retain re re- Y i t. t j tain tamn olland be worthy of ot a test teat Outside this area the La Pla Plata a Is not considered a probable oil sand Se eral Standard subsidiaries are arenow now preparing to drill as many I structures to test this formation In Southeastern Utah The Pennsylvanian Pennsyl- Pennsyl series offers excellent chances in n San Rafael swell an certain areas t farther uther east and south One proven 1 area is the old San Juan field which D produces a small amount of high grade oil oU from Pennsylvanian sands It cannot be reckoned as a big producer producer producer pro pro- ducer for the canyon of tl the San Juan river has hris cut so sa deeply that the varIous various vari varI- ous sands are exposed and anti the oil oU consequently allowed wed to escape S Some me oil has hns been retained and this furnishes t the e small production ion now being refined there It Is safe to say that the the- coming year will see at least twenty Important Import y ant tes tests ts drilled drilled and and with the excellent excellent excel excel- lent indications already found there Is every reason to expect Utah to become become be become be- be come an important oil 11 producer j I t f y 1 Y |