Abstract

Husky has extensive land holdings in the Lloydminster area, and owns additional properties in the Cold lake area. These lands contain oil fields which are shallow and relatively thin, but have good porosities. ail saturations, and permeabilities. Most of the reservoirs contain heavy oils, produce no more than 10% of the OOIP on primary production, and are good candidates for thermal EOR processes.

Pilot locations were selected using screening criteria based initially on literature guidelines, but subsequently modified to reflect field results. Since 1965 Husky has conducted a wide variety of field tests using the cyclic steam, steamflood, and in-situ combustion processes. Both successes and failures have been encountered with each process, but the operating data and experience accumulated from earlier pilots have significantly improved the performance of the later pilots. There are current successful pilots using each thermal EOR method.

A reduced effort has been made to study non-thermal EOR methods due to their limited benefit in heavy oil reservoirs. Immiscible CO, stimulation and electric stimulation have also been field tested on a limited basis.

Introduction

This paper was written to give the reader an overview of Husky's recent EOR pilot experiences in the Lloydminster and [old Lake Areas. Due to the number and scope of the projects discussed, the depth of technical detail has been purposely limited. If further information is desired, the reader is referred to the REFERENCES section.

Reservoir geology has a strong influence on the app1icabi1ity of any EOR process. However, the subject is both beyond the depth intended for this paper, and the skill of the author. Its mention is only meant to remind the reader of another aspect of EOR technology development.

The EOR projects discussed have been divided into two major types (Therma1 and Non-Therma1); and the Thermal EOR pilots have been further subdivided into cyclic steam, steam drive, and in-situ combustion. A Chronological sequence is followed within each division.

Thermal processes have been emphasized by Husky due to their applicability to the Lloydminster and Cold Lake Reservoirs. General thermal EOR screening criteria used to match the appropriate process to each candidate reservoir are listed, but it should be noted that such criteria are revised whenever new technical or economic data become available. The material in this paper documents the evolution to larger, more sophisticated, and generally more successful thermal EOR pilots which has occurred at Husky (and throughout the industry). Unfortunately, less success has been experienced with thermal processes applied to thin (3 - 5 m) sands.

Husky's efforts to develop non-thermal EOR methods are also discussed, although they are both fewer and smaller due to their apparent inapplicability to Lloydminster heavy oils reservoirs.

GEOLOGY ANO RESERVOIR DESCRIPTIONS

The Lloydminster heavy oil deposits farm the southern end of the discontinuous trend of Lower Cretaceous bitumen and heavy ail deposits which are also present in the Athabasca and Cold Lake areas. The Lloydminster deposits are unique in their ability to produce up to 10% of the OOIP under primary conditions.

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