Field experiment of in-situ oil recovery from a Utah tar sand by reverse combustion

Part of the mission of the Energy Research and Development Administration (ERDA) is to develop all energy sources to meet the needs of present and future generations. Toward that mission the Laramie Energy Research Center (LERC) is conducting research and field experiments for the development of recovery methods applicable to important supplemental sources of oil and gas. These experiments involve: (1) in situ oil recovery from oil shale, (2) underground gasification of coal, and (3) in situ oil recovery from tar sands. This report is concerned with the latter on which research was begun about 4 years ago. The objectives of this research are twofold: To determine the physical characteristics of known tar sand deposits and their probable effect on oil recovery, and to develop and field test in situ methods applicable to the recovery of oi1 from tar sands. In 1971, a laboratory was established at LERC for analysis of tar sand samples. Since then, over 3,000 samples, mostly from coring in 12 Utah deposits and a New Mexico deposit, have been analyzed. Three reports have been published (6,3,4) giving results of analysis of cores that were taken from 12 wells in the P. R. Spring deposit by the Utah Geological and Mineral Survey. Average characteristics for several of the largest Utah deposits are summarized in this report. In 1973, a study was made of in situ oil recovery methods that have potential for recovering oil from tar sands. All of the methods considered involve means for reducing viscosity as well as supplying energy for displacement of the bitumen. Reed, Reed, and Tracht (7) in 1959 reported results of experimental investigation of reverse combustion in tar sands. It was shown that the process has particular advantages for tar sand bitumen which is relatively immobile. They concluded that field application would depend on the existence of adequate air permeability to permit the required relatively high air flux to be injected. Trantham and Marx (3) reported results of reverse combustion oil recovery experiments made by Phillips Petroleum Company in 1955 to 1958 in a 60-ft. deep and 6 to 12-ft. thick tar sand near Bellamy, Missouri. In some of the tests, sustained reverse combustion was achieved in the tar sand which had average effective air permeability with bitumen and water in place of 250 md. at the time of ignition. Although there are some serious disadvantages with reverse combustion, it appeared that reverse combustion offered the best potential of known methods for in situ oil recovery from tar sands. As a result, laboratory combustion tube experiments were conducted in 1974 using tar sand from the P. R. Spring and Asphalt Ridge deposits in northeastern Utah. The purposes of these experiments was to extend this earlier work and to further evaluate the potential of the process for application to the two areas being considered for field experimental sites. Reported results (5) of these combustion tube experiments have led to the design of a field experiment. The selection and development of the field experiment site and the initiation of the first of several planned field experiments are the principal concerns of this report.