Show OIL PROSPECTS NEAR SAN DIEGO CALIF during the last few months several companies have been formed to make more thorough tests for oil in the region around san diego calif than have heretofore been made but the only one that has yet started operations is the community oil company organized by louis J wilde mayor of san diego and generally advertised as a jazz cat gamble the company first took over the old capt J F scott well in sec 4 T 19 S R 2 W about one and one half miles east of the ocean and a few hundred yards north of the mexican border this hole which is 1405 feet deep passed through feet of the san diego formation pliocene below which all the strata generated pene rated were eocene which elsewhere in california contain oil the company planned to deepen this well but was unable to clean it out next a hole was drilled close by this well but the drilling machine struck a boulder bed at a depth of seventy feet which it could not penetrate the company is said now to plan deepening an abandoned well on the north side of the north branch of choyas chocas valley a short distance east of the city limits of san diego possible oil bearing rocks of the region the rocks of san diego county may be divided into two series 1 or crystalline rocks which compose the mountains and 2 sedimentary rocks which lie west of the rocks and form a zone about twelve miles wide along the coast As or crystalline rocks are not oil bearing only the relatively narrow area of sedimentary rocks along the coast can contain oil the oldest sedimentary rocks exposed in san diego county belong to the upper cretaceous series they may be seen at point loma at pacific beach and at la jolla but as only a comparatively small part of them is uncovered their thickness is not known they are probably thick however for the dalba balba well in mission valley which was drilled to a depth of feet and which passed through the eocene series the series that immediately overlies over lies the cretaceous penetrated a great thickness of cretaceous rocks the eocene series is less than 1000 feet thick at places north of mission day bay but it may be thicker farther south A white sandstone that lies at the top of this series is prominently exposed at a number of places near delmar and torrey pines below this bed there are light colored sandstones and and a few layers of limestone certain zones in these beds are sili ferous and the fossils indicate that the eocene series at san diego should be correlated with the maganos formation middle eocene which Is exposed farther north in late in pliocene time ages after the eocene beds had been deposited the series of beds called the san diego formation was laid down these beds extend along the coast of san diego county and are probably continuous with some of the pliocene formations farther north the san diego formation differs in composition from place to place comprising beds of conglomerates sandstones and few of which are continuous over large areas in other words the formation resembles a series of lenses which differ in composition fossils are common in this formation and include several species that live in the pacific ocean today no oil however has been found in these beds sources of oil elsewhere in california the diatomaceous which belong to the eocene series and which in california are considered the main source of the oil found there are not found in san diego county their limit lies between san juan capistrano and the county line oil can therefore be obtained in san diego county only from the eocene and the cretaceous beds oil is found in california in the eocene beds at two places one on the north side of simi valley and the other north of coal inga at these places the eocene series is A much thicker than at san diego and contains that are known to be oil bearing as seeps appear here and there in the beds no oil seeps or oil impregnated sands or are known in the eocene of san diego although some oil is obtained from the cretaceous beds in california they are practically negligible as a commercial source of oil whether the cretaceous in the vicinity of san diego contains oil is not known but as no seeps or oil sands are seen at the surface and as the balboa well in mission valley which was drilled into this formation for several thousand feet afforded very little if any indications of oil the chances that this formation is oil bear ing are very slight the geological formations in san diego county are described and mapped in detail by A J evans in water supply paper of the united states geological survey department part ment of the interior structure of the beds the structure of the beds in the vicinity of san diego is different from that found at most other places in california in that the strata here lie nearly flat except at places very near faults As cretaceous rocks are exposed both on the south end of point loma and at la jolla twelve miles to the north the beds in the mission bay area which lies between these places form a syncline or trough minor undulations probably occur in the eocene beds and they may or may not appear in the cretaceous rocks below the exact structure in this region however has not yet been deter mined moreover large portions of the nia ma rine strata have been covered by the late terrace deposits which obscure a great deal of the structure wells drilled near san diego A number of wells that were carried to depths of more than a thousand feet have hate been drilled around san diego one of the first of these wells was the chula vista oil well which reached a depth of 1812 feet without striking str king oil A few years ago I a deep well was put down on the south side of otay valley by the otay oil company about the same time the lo 10 bengo oil company sank a well feet deep on tte the south side of otay mesa both these wells afforded showings of oil and gas the til tia juana well which was lately taken over overly by the community oil company went 1405 feet without encountering any oil except a questionable show two wells were put down by the san elijo oil company at sorrento the first well was sunk 1588 feet the second 1303 feet oil and gas abere arere are reported to have been noted in both wells the well at morena is reported to have gone 1200 feet without affording encouraging results the dark clark well about five miles northeast of encinitas Enci in see sec 29 T 12 S R 4 W penetrated eocene strata for 2125 feet without showing any oil the most recent well to be abandoned was the balboa well in mission valley which was drilled to a depth of feet this well disclosed the interesting fact that sedimentary beds more than a mile thick underlie this part of san diego county the greater part of these beds belong to the cretaceous system but whether they lie ak a proximately flat as do the ilie overlying eocene beds has not been determined possibly they are somewhat folded so that the dl distance drilled is more than the actual thick ness of the beds recent geological examination the region was recently examined by william S W kew of the united states of the I 1 IB geological survey department gerior who is of opinion that san vego county is not a favorable place in which drill test wells for oil the reasons for i this opinion can be summarized as follo follows 1 the principal formations that W oil elsewhere in california are not found in san diego county 2 the upper crew cretaceous I 1 strata which probably constitute large part of the sedimentary beds of S diego are not commercially productive in other parts of california and there is no noth ing to indicate that they will be productive P g in the southern part of the state 3 eocene strata though of the sanle same age a the oil bearing strata in other parts of calls fornia do not appear to contain oil here that As far as known no structural features are favorable to the accumulation of 0 09 such as anticlines anti clines have been discovered discover 10 san diego county |