October 31, 1975 - Gerald R. Ford Presidential Library and Museum

The Bay Marchand Block 2 field is located just offshore from Lafourche
Parish in southern Louisiana about 60 miles south of New Orleans in
the offshore Miocene belt.
There are more than 125 individual sand members at Bay Marchand in
a thick sand-shale sequence of predominately Miocene age. They occur
from 1,200 feet to 16,000 feet.
The structure at Bay Marchand is related to a shallow piercement type
salt dome which is one of the largest in the world (about nine miles
in diameter at the 18,000 foot level). The field is highly faulted.
The combination of faults and numerous sands has caused more than 500
individual stratigraphic or fault block reservoirs in the field. Some
are superdomal at the crest; others are controlled by salt or shale
truncation; and still others are sand pinchout situations. Faulting
plays a major part in the delineation of the reservoirs. Most segments
are underlain by bottom water. The field has about 13,900
production acres (22 square miles).
A volumetric analysis to determine hydrocarbons originally in place
in each of the many individual reservoir segments was not practical.
However such calculations were made for reservoirs which were being
water flooded on the east, south, and west flanks of the field. Also,
volumetric analyses were carried out for the nonas.sQciate.d gas:reservoirs
at Bay Marchand.
The primary producing mechanisms are combinations of dissolved gas
drive, gas cap drive, and partial water drive. In addition, numerous
segments are being water flooded. The consultant firm estimated
ultimate recovery by the process of interpretation of production
decline, well test, and water/Qil ratio! data in the reservoir segments
not being water flooded. In the other reservoir segments (including
nonassociated gas reservoirs), reserves were estimated by assigning
recovery efficiency factors to estimates of hydrocarbons originally
in place, and then by adjusting the predictive data to the various
production decline curves. This appears to be a very reasonable
and practical manner of handling a most tedious situation in the
ti me span allotted. The overa 11 recovery effi ci enci es came down to
46 percent of oil and 71 percent of gas originally in place.
The FEA report on the Bay Marchand Block 2 Field was prepared by
Keplinger and Associates, Inc., under Contract No. CO-05-50l84-00.
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