Abstract
American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the Improved Oil Recovery Symposium of the Society of Petroleum Engineers of AIME, to be held in Tulsa, Okla., March 22–24, 1976. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and with the paper, may be considered for publication in one of the two SPE magazines.
Abstract
For moderately viscous oils (50–200 cp), such as those occurring in several oil reservoirs of Wyoming and California, it may be economical to employ non-thermal oil recovery methods, as opposed to the conventional steam-and fire-flooding techniques. In the past, a wide variety of nonthermal heavy oil recovery methods have been tested, with limited success. These methods range from waterflooding to improved floods and "pattern rotation" type techniques. This paper presents a comprehensive survey of the nonthermal heavy oil recovery methods, which have been tested in field and laboratory. Specifically, waterflooding, emulsion flooding, solvent and carbon dioxide displacement processes, and their variations, are discussed. processes, and their variations, are discussed. Field test results are given, where applicable. The prospects of such heavy oil recovery method are considered in relation to thermal recovery techniques.
Introduction
Heavy oil deposits in the U.S., Canada, Venezuela, and other countries are an important resource, totalling several trillion bar ls. In the U.S. alone, there are over 2,000 heavy oil reservoirs occurring in 1500 fields in 26 state" The total resource is estimated at 106.8 billion barrels, of which some 45.9 billion barrels may be eventually recovered by thermal oil recovery methods. The remaining 60.9 billion barrels occur in fields which do not offer favorable conditions for the application of thermal methods, viz. steam injection and in situ combustion. The existing conditions include such factors as thin formations (less than 30 ft.), excessive depths (is greater than 3,000 ft.), low formation permeability (less than a darcy), precluding high enough injection rates, too low precluding high enough injection rates, too low an oil viscosity (50–200 cp), low oil saturation, perhaps in combination with a low porosity and large formation thickness, etc. Under such conditions, it may be possible to employ a nonthermal oil recovery method, which may be modified for a moderately viscous oil. This is essentially the subject of this paper. Specifically, it is intended to consider the recovery methods which may be applicable in reservoirs containing oil with viscosities less than a few hundred centipoises. Selected instances of more viscous oils, where non-thermal methods may be effective, will also be cited.
On the basis of the published literature, there are at least 23 fields in the U.S. (68), and as many abroad (36), in which the oil viscosity at reservoir conditions ranges from 50 to 200 cp. The U.S. fields and the oil and formation characteristics are listed in Table 1. It is seen that most of these fields are in California and Wyoming.