Oil Fields in Igneous Rocks in Coastal Plain of Texas

Abstract

Oil produced in commercial quantities from igneous rock in the Cretaceous formations of the Gulf Coastal Plain of Texas is obtained from eight fields as follows: Thrall, Chapman, Yoast, Lytton Springs, Dale, Buchanan, Lytton Springs townsite, and Schimmel-Batts. Showings of oil in igneous rock have been found at several other localities. The rock containing the oil was originally basaltic in character, but has been changed by alteration to chlorite or serpentine. It is probably largely extrusive in origin, but may be, in small part, intrusive. Porosity is present in variable amounts and production is irregularly distributed in each field, many dry wells offsetting good producers. Initial production varies from a few to 5,000 or more barrels. The igneous rock in the produc ng fields lies chiefly at or near the base of the Taylor marl. The oil is of paraffine base and high gravity, usually 38°-39° Be., although in one field it is as low as 27° Be. It is accompanied usually by very little water. Drilling is by rotary tools and largely through soft formations. Ultimate production to the acre will range in different fields from 1,200 to 10,000 barrels.