| Show oil problems in in the uinta basin bas n IV by prof earl douglass NOTE ifor for a description of asphalt deposits of the uinta basin see the asphalt and bituminous rock deposits of the uinta geo eo H eldredge twenty second rep U S geol sarv vol 1 pp ap surface indications gi gilsonite Is 0 nite I 1 in n studying the surface ace indications of oil we ave will begin with avith more commonly called gilsonite as it is the hydrocarbon which i is S most abundant and has attracted the most widespread interest nt erest this with the other hydrocarbons is recognized Is an oxidized residue which remains after the vaporize 1 on oil of the more volatile constituents of petroleum so if ye e can call trace its ori origin 6 in and history it ought b to take us a on ong way toward the solution of the oil problem one who is impressed with natural phenomena and athral curiosities will avill hardly forget the impressions made joaie I 1 y the first sight of a large open vein of this clean black hill chiny y hydrocarbon which fills the space between the clean ut vertically parted walls of sandstone or sandy nd extend for miles in either direction i some of the questions which ily illy arise sooner or later if he thinks much uch of tell teh matter are k what is it where did it come from how did it get et here why are the walls so strai straight ht and moth lookin looking as if they had been cut pen open for the purpose of holding the Is onite byh are they almost perfectly per endi cular why do the veins nearly all extend n the same direction r why is the appearance next to the alls ails usually somewhat from n hat at in the middle of the veins why do the veins occur in this par icolar formation dunles the mineral was formed when he rocks were formed it must have been oft when en it came into the fissures if so yat hat held the fissures open until it hardened fiss fissures utes beneath if this had occurred would the upper portions of the fissures have remained open did the material come from the surrounding rock if so this of course would be it is said that a fool can ask more questions than several wise avise men can call answer these however are not fool questions but those which a wise man will surely try to answer if lie he is going to invest his money in prospecting for oil here there seems to be at least one encouraging C smile on the face of this sphinx the lighter constituents of petroleum escape in the presence of the atmosphere so one would naturally suppose that the forming of the viscid or solid hydrocarbons would take place near the surface of the earth if so perhaps it is 6 going on yet and can be observed or if not we may find where it has taken place besides the theory stated and quoted by geologists N T w AT outcropping cropping Out of gilsonite disunite vein cin in the ot of the middle Uin tali fori nation in line vitia excavation in foreground may ina he be seen een many nian much openings long along the vein ein for a great distance I 1 the te veins remained open why instead of ure gilsonite do we not find it mixed with rocks vegetation and debris etc from the surface why like wells prospect holes etc do these fissures ot serve as traps to catch rabbits mice and other ani als recent and extinct thus preserving their skeletons in e gilsonite Ss onite something as they are preserved in the r laces asphalt beds near los X angeles in california and in other r if this is the heavier residue of petroleum what became f the lighter lighter or more volatile portions where here when and under what conditions did this or vaporization and oxidization n take place Is W could it take place le deep P in m the earth where there ri little ittle atmosphere and no currents of air to carry off the batile portions ao As the go g down sev several eral hundred feet at least buld could it come up tip from beneath as it has been sur iced that it did it has been inferred that it came up under pressure hat nat could have forced it up tip unless by the closing of the that asp came from pressure heard another theory stated orally it was avas in substance as follows before erosion had proceeded so far there was a lake of liquid asphalt similar to the pitch lakes of trinidad and venezuela the earth was fissured beneath and the asphalt descended into the fissures tile the site of the lake or lakes was later eroded away and the hardened veins came to view I 1 have laughed at this but after all is it not as rational as the theory that the gilsonite came from below under pressure and haac hav we any right to say without a fair investigation that it is not nearer to the truth tile the question as to what gilsonite is has been discussed in previous articles but we ave will avill repeat the definition here it is on oil the uinta railway stage line on the bench land north of white river that some of the larger b gilsonite veins can be most conveniently seen and the narrow guage uinta railway line was built into the basin to furnish transportation por tation for the gilsonite in several places the veins have been worked for the ore and the trend can be traced over the ilie open country for miles as they are marked by piles of the gilsonite which have been thrown wn out in doing assessment work the direction of the veins reins approximate a northwest and southeast direction they are therefore nearly parallel yet not exactly so it is said that the little bonanza and bi big 6 bonanza veins converge until to the southeastward wards towards t 0 the white hite river they unite into one large vein this group consists of at least five veins the cowboy the little bonanza the big bonanza the cha pita and the Wagon hound the trend of which is almost uniformly N 60 W according to eldredge they are exposed for a distance of fr from froin oin one and a half to ten or eleven miles but the they probably extend much enuch farther they terminate to the southeastward at the escarpment of the white river canyon where the uinta sandstones which contain the larger veins end havin having b been eroded away to the southward to the northwestward the lower uinta and middle uinta deposits extend under the upper uinta deposits which are composed principally of clay and sand with bands of sandstone here the veins become narrow and I 1 believe aladie all die out the clays have apparently taken up the stress without fissuring this condition will again A 7 0 ar qa 4 a vein of gilsonite sit at little bonanza uintah county the tim timbers lers are placed as seen to prevent the alie fissure front from cl up be referred to later as a probable explanation of one of the questions asked above it is probable then that the larger veins extend under the covering b of the upper uinta for a considerable distance perhaps s much greater than the length of the exposed portions in width the veins vary from a foot or two to sixteen or eighteen feet 0 on closer examination it is seen that in linear extent the veins are slightly an sinuous and looking down in them from above the walls are sometimes seen to be somewhat wavy southeastward from this group of veins which we anve will call the bonanza group is a wide band of exposure of the lower and middle beds of the uinta in the area of the white river and its southern tributaries tributa ries traversing this region in apparently patently ap parent ly the same saine direction are two or more successive bands or zones of gilsonite veins As in the group already described there are usually five or six principal veins the zones are about four or five miles in width and the iless or nearly bands between are of about the same width if the mapping of eldredge and my observations are correct see plate opposite p in report of eldredge the next zone southwestward eastward from the bonanza roup group extends southeastward to dragon drag on on evacuation cree crecli J and includes the rainbow the ute veins and the blad blac dragon in its extension to the northwestward this zon includes the duchesne and its apparently comp companion anion ion y vei e or veins near ft duchesne the extreme exposures ures a ar about sixty miles apart As now known then the e eitrem X t rem len lenth length th of the area containing large veins is at last sixt six miles in a northwest and southeast direction and about fort miles in width at right angles to this the more wester and northwestern veins including the fariette Pa riette and duches veins do not trend so much to the westward as the moi mo eastern veins according to eldredge their course is N y 3 to 40 W prof eldredge made estimates of the quantities I 1 gilsonite ils onite in the larger workable veins the cowboy litt lit fl bonanza big bonanza black dragon rainbow calme duchesne and colorado his estimates were probably f below the actual amount as he took into consideration on the length of the veins actually exposed As above stat they probably extent under the upper uinta deposits the northward where these beds are not eroded away the estimate of eldredge g is near nea ra tons the amount of reside t which does not include the smaller yd vein or perhaps all the large ones certai nl represents a large amount of petroleum we speak of oils as thos tho with a base and oi oil as those with an asphalt base A lar larg p proportion ro portion of the oils contain both para fine and asphalt but one or the 0 othe usually y predominates though we h hav here immense deposits of asphalt of var vai 10 ious us kinds we cannot say yet v whether th oil which the they y produced was vas v a ligh gh or a heavy asphalt oil ailo D her it was an intermediate it i 1 possible that before we get through h w may be able to make a good guess in the f few tables of analyses of P pe to which I 1 now have access th tb asphalt res residue 1 idue runs from ze zero ro up t ti 33 but the heavier oils are edly thickened by evaporation of th lighter constituents like some some in ill call cal fornia for example it seems to me that an average of one pound of resia from a gallon of oil 1212 would not be an unreasonable es dimate for our purpose which is to get some faint idea of 0 the amount of oil which the gilsonite ils onite represents on this L b of 01 basis then the tons or pou aids ZA so b gilsonite would represent 6 gallons or I 1 S barrels of petroleum that is not very much you may say in this a be of big thins things al but it is alto altogether b ether too much to ignore SUP P in pose too that it should turn out that this has conle come fron ir it a comparatively small part of the area might inight run into large figures to in the next article we will try to trace these eveln see whence they came or whither they go go As these ar articles are preliminary studies and the author in his iso isolated poll P tion has no access to any library except his 01 own takes will inevitably occur it is the truth that is des j and he will be glad to have his attention called to any erlof er j which may occur 1 |
