Abstract

This paper gives an overview of the emulsion research program at the Petroleum Division of the Saskatchewan Research Council. The program consists of four areas of research:

  1. field monitoring and emulsion characterization,

  2. research into emulsion separation by physical and mechanical means,

  3. construction and operation of a mobile emulsion treating pilot plant, and

  4. flow improvement through oil-in-water emulsification. Each of these areas is described and a summary of recent results is presented.

Introduction

Alberta and Saskatchewan have very large resources of bitumen and heavy oil, but due to the1r high viscosity only a fraction of these resources can be produced by primary and secondary means. Tertiary recovery processes that reduce these high viscosities are required to unlock these petroleum resources. The most successful enhanced recovery techniques presently being used make use of heat for Viscosity reduction. Of these thermal processes steamflood1ng is the most common and the one used in thicker formations, while in-situ combustion is applied on a smaller scale and in thinner formations.

Since the majority of the heavy oil reservoirs in the Lloydminster area falls with1n the thin category I the use of in-situ combust1on is expected to increase Significantly in the future. This, in turn, Will place a much heavier burden on the surface treating facilities which must bring the produced oil, an emulsified mixture of water and oil, up to pipel1ne specifications. The reason is that, wh1le heavy oil emulsions produced by pr1mary means and steam flooding can be treated relatively easily, those from in-situ combustion require progressively severer and costlier treatment as the flood progresses. In fact, present technology is occasionally unable to cope with tight fire flood emulsions, necessitating shutting in the of fend1ing wells. Therefore, development of more efficient emulsion treatment methods is an essential requirement For the successful expansion of in-situ combustion. In recognition of this need, an emulsion research program was established at the Petroleum Division of the Saskatchewan Research Council (SRC) five years ago.

A three-pronged approach was initially adopted for SRC's emulsion research program, namely (i) implementation of a comprehensive field monitoring/ emulsion characterization program; (ii) research in and development of new or improved physical and chemical demulsification techniques:; and (iii) construction and operation of a mobile emulsion treating pilot plant. A fourth area, flow improvement through oil-in-water emulsification, was added two years ago as a result of industry interest.

The field monitoring program, involving the regular sampling and characterization of wellhead fluids/emulsions from various thermal projects in Saskatchewan (Battrum, Meota, Eyehill and Lone Rock), was started in order to study the changes in the produced fluids as the flood progresses. Following these changes has not only contributed to the understanding of emulsion formation, but the knowledge may also be used to alert operators of upcoming emulsion and corrosion problems. In parallel with the field program, emulsions are also being synthesized in the laboratory under simulated reservoir conditions to study the effects of various reservoir and fire flood parameters on emulsion characteristics.

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