218 Proceedings of Indiana Academy of Science 
the gas produced between the ten and twelve inch casing. The gas is 
then used for operating purposes while the well was then drilled to the 
oil sand. This sand is lenticular in character and varies considerably 
in thickness. The depth at which this sand is found varies with the 
position of the well on the structure and with the elevation of the well. 
If the well is on top of the structure the sand is found at a much 
shallower depth than when located off the top of the structure. The 
sand lies almost uniformly 625 to 650 feet above the Hewitt Sand Zone. 
Stray Oil Sands.—There are several stray oil sands found above 
the Hewitt sand and below the 600 foot gas sand. These sands vary 
from 70 to 300 feet above the Hewitt sands. These sands are not 
regular and are of but small extent. Wells drilled to these stray sands 
vary greatly in initial production, and do not hold up in the amount 
of oil produced for very long. The initial production of wells drilled 
to these sands is from 25 to 200 barrels per day. 
Hewitt Sand Zone.—The Hewitt Sand Zone includes a zone 600 
to 700 feet in thickness made up of oil bearing sands, shales, sandy 
shales and dry sands but no water sands occur in this zone. 
The first or main sand in the Hewitt Sand Zone has been the main 
producing sand in the Hewitt field. This sand is surprisingly contin- 
uous and is the datum used in making the subsurface structure map of 
this area. This first or main sand was the principal producing sand until 
November, 1920, when deeper drilling showed that some of the deeper 
sands were of more importance. This main sand is found in wells 
on top of the structure as shallow as 1,200 feet in the north central 
part of section 22-4S-2W and as deep as 2,100 to 2,300 feet along the 
north line of section 27-4S-2W. This sand dips at the rate of 1,200 feet 
to the mile to the west and 1,000 feet per mile toward the south. 
The Hewitt Sand Zone is capped by a blue shale interval of about 
400 feet with hardly a break. This shale separates the oil sands and 
the higher water bearing sands and also prevents the migration upward 
of the oil thus leaving the sands of the Hewitt Zone barren of oil. 
The sands of the Hewitt Zone are soft, porous, and usually white 
and gray in color. The sand varies in porosity and size of grains. This 
variation in porosity and in the size of grains accounts for the differ- 
ence in production of the various wells. The heaviest production comes 
from wells where the sand is fine grained and loose. The lighter pro- 
duction comes from sands with coarser grains and more firmly cemented 
but still comparatively soft. 
Deeper sands in the Hewitt Sand Zone have been found to be of 
considerable importance. The intervals to these deeper sands are not 
constant due to the lenticular character of the sands. A few sands of 
importance have been found which persist with fair regularity in most 
parts of the field. 
A second sand of importance about 75 to 100 feet below the main 
or top sand has been found in most parts of the field. In all cases this 
sand, when drilled into, increases the production of the wells. Occa- 
sionally in some parts of the field this sand is more prolific than the 
main sand. This sand when wells are deepened to it increases the pro- 
duction 20 to 100 barrels per day. 
