Characteristics of the Eocene Elko Formation, a Lacustrine Sedimentary Section Located in North Eastern Nevada and Comparison of Open Hole of Wireline Logs With Well Site Geologic Observations and Core Data

Abstract

The Eocene Elko formation is a lacustrine hydrocarbon source rock located in North Eastern Nevada. The areal extent of the ancestral Lower Tertiary Elko basin is restricted primarily to Elko County, Nevada, and encompasses an area of nearly 8,000 square miles. The Elko oil shale was first recognized by R.M. Catlin in 1875. Ultimately, an oil retort was built and operated from 1917 to 1924 by Catlin producing approximately 12,000 barrels of oil. The Elko formation consists of interbedded shale, siltstone, sandstone, carbonates (limestone and dolomite) and volcanic rocks. In the Noble K1L well the total thickness of the Elko formation is 2055 feet thick (7384’ to 9439’) with organic rich shales from 8734’ to 9439’. Noble obtained a 396’ continuous core of the organic rich shale section from 8830’ to 9226’ with nearly 100% recovery. The entire core currently resides at the Nevada Bureau of mines and Geology (NBMG) Great Basin Science Sample and Records Library (GBSSRL) in Reno, Nevada. In 2014 Noble perforated 25 feet of the organic rich shale in the Noble K1L well between 8924’ and 9290’. The well produced 3831 barrels of 42.4 API gravity oil with a pour point of 95F. The well was plugged and abandoned in 2017. This completion zone includes most of the cored interval providing a unique opportunity to compare production zones with a continuous whole core.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018