Abstract

A light oil steamflood pilot (LOSF) in the Shallow Oil Zone (SOZ) is under evaluation at the Naval Petroleum Reserve No. 1 (NPR-1), the Elk Hills field in Kern County, California. The Shallow Oil Zone is defined by the Elk Hills Engineering Committee as all oil and gas bearing rocks of Pliocene age above the Reef Ridge Shale, except the dry gas-bearing rocks above the top of the Scalez marker bed. The Sub-Scalez I (SS-1) of the SOZ is the formation steam being injected. The SS-1 is a unit of the Scalez sand zone in the San Joaquin Formation of Pliocene age.

From a reservoir perspective, the steamdrive process is behaving in a sequence of predicted events. The first expected event was the appearance of fresh water accompanied by carbon dioxide at the producing wells; this happened 3 months after the start of steam injection. The second event, an increase in API gravity of produced crude, appeared 3 months later or 6 months into the project. Finally, the arrival of the heat front at producing wells was detected 13 months after startup.