The stratigraphy and structure of Hitchcock field, located about 40 miles southeast of Houston, are discussed in light of the 27 wells drilled there since Halbouty and Simmons' original study in 1941. The producing structure appears to be an east-west anticline, the crest of which has been downfaulted to form a graben. Maximum stratigraphic throw of the faults in the field is 280 feet. The large regional strike fault that passes north of the field has a stratigraphic throw of 830 feet. The greatest structural growth seems to have occurred during late Miocene or early Pliocene time.

The sand in which oil was first discovered (5,100-foot sand) is still the most important reservoir in the field. It is absent over the crest of the anticline, but is present on the west, south, and east flanks.

Cumulative production from Hitchcock field through 1957 was 4,115,421 barrels of oil, 1,889 barrels of condensate, and 1,180,919 MCF of gas. All of the oil and most of the gas come from the Miocene. Some gas is produced from the Pliocene. Three wells drilled to the Oligocene Frio sands failed to find production in that section.

End_of_Article - Last_Page 2515------------