Steam DisplacementKern River Field

Abstract

The heat has been on in Kern River since the mid fifties. First it came from bottom-hole heaters, then it came from injected hot water. In 1964 a steam drive was started, so that currently the field is sweating out 6,700 barrels a day as a result of a daily injection of 30,000 barrels of steam. Introduction The Kern River field is a few miles northeast of Bakersfield in the southeastern part of the San Joaquin Valley. It is one of the largest in California in terms of its original oil in place and cumulative production. The latter, as of Jan. 1, 1969, was production. The latter, as of Jan. 1, 1969, was approximately 476 million bbl. On the 12,100 productive acres there are more than 5,100 active productive acres there are more than 5,100 active producing wells, ranging in depth from 500 to 1,300 ft producing wells, ranging in depth from 500 to 1,300 ft The reservoir and fluid characteristics of the Kern River field are considered favorable for secondary recovery by steam displacement. The gravity of the produced oil ranges from 12 degrees to as high as 16.5 produced oil ranges from 12 degrees to as high as 16.5 degrees API, and averages about 13.5 degrees The oil has an average viscosity of 4,000 cp at the reservoir temperature of 90 degrees F. At 250 degrees F, this viscosity is reduced to 15 cp. The structure of the Kern River field is a simple homocline on the east flank of the San Joaquin Geosyncline, dipping toward the southwest at 4 degrees. The productive zone is an unconsolidated sand with considerable dispersed silt interbedded in blue-green clays. Average permeability of the oil sand is approximately 4,000 md. The Kern River formation represents a continental-alluvial fan deposit derived largely from the westward-flowing Kern River. History of Development The application of heat to the Kern River sands dates from the mid 1950's, when bottom-hole heaters were installed to assist in the recovery of the heavy crude by improving the mobility of the oil, reducing plugging of the perforations, and improving pump plugging of the perforations, and improving pump performance. performance. Based on the successful program of bottom-hole heaters in the field, further investigations were undertaken to utilize the heat more effectively in producing the viscous oil. Theoretical performance predictions made a hot waterflood attractive, and in 1961 it was considered necessary to conduct some fundamental displacement experiments to verify the predictions. The results of the laboratory experiments were encouraging, and in Aug., 1962, a 2 1/2-acre nominal five-spot pattern was dried and a pilot hot waterflood was begun. Hot Waterflood Pilot Performance A total of 2,231,000 bbl of hot water was injected into the four injection wells from Aug., 1962, to Feb., 1964. Results from the hot-water injection project showed that viscous oil displacement by hot waterflooding was mechanically feasible. However, because of inherent reservoir conditions that caused excessive bypassing and channelling at the required high injection rates, the method was not economically attractive. It was concluded that to develop economic process, the sweep efficiency of the displacing phase had to be increased substantially either by eliminating the observed channelling or by increasing the heat utilization efficiency. Steam Displacement Steam as a heat carrier and displacing fluid was considered potentially capable of producing the necessary improvement in heat utilization. JPT P. 1225