DETAILS OF THE DEVELOPED TERRITORY. 
97 
little consequence as regards production. The thickness of zone A 
in the wells ranges from 8 or 10 to nearly 150 feet, but several more 
or less important oil-bearing zones lie between this and the next 
lower (B) zone. The productive measures of zone A consist largely 
of brown shale, probably seamed or jointed in such a way as to afford 
a reservoir for the oil, although certain of the wells may obtain their 
product from fine-grained sands int erst ratified with the shale. 
The second oil zone (B) is the most important one in this area, 
although it is underlain over at least a part of the area by zone C, which 
is apparently even more productive. The thickness of zone B is 
variable, but most of the wells penetrate from 50 to 150 feet of pro¬ 
ductive strata at this horizon. The oil-bearing beds are similar to 
those of zone A and appear to consist largely of hard shales, with 
some fine sands, although some excellent examples of a true siliceous 
sand are obtained in many of the wells. A hard limestone “shell” 
overlies zone B in one well. 
The third oil zone (C) is penetrated by some of the deeper wells 
at a depth of about 300 to 400 feet below zone B. In one of the 
wells zone C appears to be missing, although a good flow of oil is 
reported from the same hole about 500 feet below where it should 
occur. 
Water underlies oil-zone B in one of the wells and zone C in another. 
This occurrence of water below the oil, so common in most fields, 
is very rare in this one. Whether or not in the course of time water 
will follow up the oil in the productive zones is something that will 
be awaited with a great deal of interest. Some of the wells in the 
Santa Maria field have been stopped in the midst of productive strata 
for fear of encountering water farther down, but whether or not 
these fears were well founded has never been established. 
PRODUCT. 
The oil from this group of wells is of a dark-brown color and 
ranges in gravity from 24° to 28° Bauine, the lighter oil usually occur¬ 
ring in the wells nearest the main anticline; the average gravity is 
between 25° and 26°. Much gas is associated with the oil in all the 
wells. 
The production of the individual wells ranges from 60 to 1,000 
barrels per day, the latter amount coming from a hole very eccentric 
in its behavior, as shown by its yield of 200 barrels on some days 
and as high as 1,000 on others; the average daily production for this 
well is 300 barrels. With the eccentric well omitted, the maximum 
production is about 500 barrels per day. One well which produced 
150 barrels from zones A and B added 350 barrels to its output when 
deepened to zone C. 
