Dineh-Bi-Keyah Field, Apache County, Arizona: ABSTRACT

Abstract

The Dineh-Bi-Keyah oil field is located on the Navaho Indian Reservation in northeastern Apache County, Arizona, and is situated on the northwest end of the Toadlena anticline, a surface feature on the northeast flank of the Defiance uplift. The field is producing from a syenite sill which intruded Lower Pennsylvanian rocks. The discovery well was completed in January 1967 and as of October 1, 1979, the field has produced a total of 15,386,725 bbl of oil. The sill is of Tertiary age and contains both intercrystalline and fracture porosity. Primary minerals are sanidine, biotite, diopsidic augite, glass, and minor magnetite. Glass is the primary cementing material. The porosity, permeability, and oil-saturation values measured in the igneous rock are similar to the reservoir parameters of many oil-producing carbonate rocks. The sill is comparable in general appearance and mineral composition with plugs, dikes, and sills that crop out in the area. However, the igneous rocks exposed at the surface in the area are very fine grained and dense and have little, if any, porosity. Samples from the two igneous plugs which crop out at Roof Butte, 1 mi (1.6 km) southeast of the discovery well, are difficult to distinguish from core chips from the dense parts of the producing formation. End_of_Article - Last_Page 696------------