Oil from Igneous Rock - A Review of Operations in Dineh-bi-Keyah Field
Authors: Williams C.D. , Roth Gary E. 
Published: December 2007

Introduction
The Diney-bi-Keyah field, located on the Navajo Indian Reservation in northeastern Arizona,, is approximately 50 miles southwest of Farmington, N. M. Geologically, Dineh-bi-Keyah is located on the northwest end of the Toadlena Anticline which is a large northwest-southeast trending surface feature that parallels the Defiance Uplift on its northeastern flank. Dineh-bi-Keyah is of unusual interest to the petroleum industry in that the reservoir rock petroleum industry in that the reservoir rock or producing horizon is an igneous sill of Tertiary age that intruded lower Pennsylvanian limestones and shales.
The discovery well, Kerr-McGee Corp. Navajo No. 1, was completed early in Feb., 1967, pumping 648 BOPD. Fifteen wells are producing pumping 648 BOPD. Fifteen wells are producing an average rate of 7,200 BOPD. Twelve of these wells are operated by Kerr-McGee Corp. and three by Humble Oil and Refining Co. Cumulative production to Jan. 31., 1969, was 6,316,577 production to Jan. 31., 1969, was 6,316,577 bbl.

RESERVOIR AND PRODUCTION DATA
Reservoir rock is a dark gray to greenish gray syenite sill. The principal minerals are sanidine, biotite, diopsidic augite, glass and magnitite. The rock texture ranges from dense and fine grain to medium and coarse crystalline with pinpoint to vuggy porosity. Extensive vertical and horizontal fractures have been noted in some of the cores taken of the sill. Therefore, porosity in the sill is of intergranular, vugular and fracture types. Core analysis of the sill showed porosity ranging from 5 to 17 percent, permeability ranging from less than 0.01 md to 25 md, and water saturation ranging from 25 percent in permeable sections to 93 percent in zones of very low permeability. The sill ranges in thickness from 38 permeability. The sill ranges in thickness from 38 ft to 174 ft and is known to cover approximately 3,000 acres. Average values generally accepted are porosity of 10 percent, water saturation of 45 percent and gross pay thickness of 95 ft.
In a few of the wells, the sill is split into more than one segment. Generally, the best producing wells are in the southeastern part of producing wells are in the southeastern part of the field. Production of 3,694,914 bbl or 58.5 percent of the cumulative has come from the percent of the cumulative has come from the four wells, Kerr-McGee Navajo No. 1, No. 2, No. 3X and No. 4, located in Section 32, T36N, R30E. The producing ability appears to be related to the natural fracture system in the vicinity of the wellbore. Sill was penetrated in four wells, Kerr-McGee Navajo No. 5, Navajo "B" No. 1, Navajo "F" No. 1, and Humble No. 4-88, from which oil production could not be established. Probably these wells fell in an area of lower natural fractures. Recovery from the reservoir in the vicinity of these wells is expected to be very small. The reservoir energy apparently is being furnished by solution gas drive. No evidence of water drive has been found, although all wells in the field produce some water with an average water cut of produce some water with an average water cut of around 15 percent.