PUBLICATION RIGHTS RESERVED PUBLICATION RIGHTS RESERVED THIS PAPER IS TO BE PRESENTED AT THE INTERNATIONAL TECHNICAL MEETING JOINTLY HOSTED BY THE PETROLEUM SOCIETY OF CIM AND THE SOCIETY OF PETROLEUM ENGINEERS IN CALGARY, JUNE 10 TO 13, 1990. DISCUSSION OF THIS PAPER IS INVITED. SUCH DISCUSSION MAY BE PRESENTED AT THE MEETING AND WILL BE CONSIDERED FOR PUBLICATION IN CIM AND SPE JOURNALS IF FILED IN WRITING WITH THE TECHNICAL PROGRAM CHAIRMAN PRIOR TO THE CONCLUSION OF THE MEETING.

Abstract

In 1984, Texaco initiated a field test of multizone thermal recovery with dually-completed injection wells. With a single tubing string and packer, a concentric injection arrangement was implemented. Hot water was injected down the tubing into a previously-steamflooded sand, while previously-steamflooded sand, while high-quality steam was injected down the tubing-casing annulus into an overlying active steamflood zone. While both floods have demonstrated favorable production behavior, the heat transfer between the tubing and annulus has had a major impact on the planned injection strategy, with indications that the "hot waterflood" has actually been a low to mid-quality steamflood for most of its project life. Furthermore, regional gravity drainage has unexpectedly been a dominant recovery mechanism in the lower zone, creating regions of distinct production characteristics within the project area.

This paper analyzes the field results from the first 2-1/2 years of the dual injection project and discusses the identified recovery project and discusses the identified recovery mechanisms in addition to the heat transfer consequences of dual steam/hot water injection.

Introduction

The Kern River Field is a 10,000 acre (4000 ha), shallow, heavy-oil deposit located near Bakersfield, California. The reservoir is comprised of up to seven sand members that are separated by silt and clay interbeds. The structure of the field is a simple homocline dipping at 3-6 degrees to the southwest. Oil sands are present at depths of 400-1400 feet (122- 427 m). The unconsolidated sands have high permeabilities of 1 to 5 darcies and permeabilities of 1 to 5 darcies and porosities of 28% to 33%. The produced oil porosities of 28% to 33%. The produced oil gravities range from 90 to 16 degrees API, and the corresponding viscosities also vary from 10,000 to 600 cp (10.0 to 0.6 pa S) at 100 degrees F (38 degrees C).

Since heat effectively reduces the viscosity of the crude, thermal recovery operations have long played a major role in the development of the Kern River oil sands, with steamflooding the preferred process among the various operators. There have been numerous publications on steamflooding in Kern River publications on steamflooding in Kern River attesting to the success of the steamflood process. process. More recently, there has been interest in following high-quality steam injection with low-quality steam or hot water.

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