Low Temperature Oxidation Process For the Recovery of Bitumen

Abstract

Abstract A three-dimensional physical si1nulator was used to carry out experiments on a variety of novel processes for the in situ recovery of bitumen from the Athabasca oil sands deposit. Runs were made at up to 500 psi operating pressure. The low temperature oxidation process, comprising combinations of air and steam, was shown on the basis of the laboratory data to be a most promising recovery technique. The paper compares the performance of the low temperature oxidation process with a straight steam displacement process and describes the factors which determine the optimum performance and the mechanisms which are believed to contribute to the effectiveness of the process. INTRODUCTION There is a growing recognition of the role which the Alberta oil sands deposits could play in providing for Canada's future energy needs. Research and development of processes for the in situ recovery of bitumen have been correspondingly accelerated, and many organizations are involved in the effort at both the laboratory and field level. The main thrust of this research has undoubtedly been to adapt thermal recovery processes which have been operated with varying degrees of success in heavy oil reservoirs in the United States, Venezuela, and elsewhere. The most promising processes for the Alberta oil sands are generally considered to be steam drive, steam stimulation and wet combustion. Of course, the possibility of more exotic recovery processes, such as those discussed by Flock and Tharin,(1) being brought to eventual commercial fulfillment, should also be considered. Nevertheless, the consensus would probably be that the first commercial in situ. recovery scheme will be based on known thermal recovery technology. The special problems posed by the Alberta deposits, when compared with heavy oil reservoirs elsewhere, are well-known and have been thoroughly discussed by several authors.(2,3,4) It appears likely that the known processes will need at the very least to operate at their full potential and, more probably, require improvement. Texaco Exploration Canada Ltd. has been actively involved since 1971 in the development of a commercially viable in situ recovery process for the Athabasca deposit, through its pilot project located some 12 miles south-east of Fort McMurray, and through an intensive research program carried out under contract by the Alberta Research Council. Results from the field program have been sufficiently encouraging to warrant an expansion of the number of wells and of the pilot facilities, which was undertaken in 1975–76. The laboratory program has involved an extensive investigation of a variety of in situ recovery processes for the Athabasca deposit. Much of the effort in this program has been devoted to the development of improvements to the steam drive process. In this paper we present the results of experiments involving the simultaneous injection of non-condensible gases and steam. Of the gases studied, air showed the most promise of being an additive which could markedly enhance the recovery of bitumen relative to steam alone, and combinations of air and steam were studied in some depth.