Solvents and Explosives To Recover Heavy Oil - A Pilot Demonstration

Abstract

ERDA engineers are investigating a heavy-oil reservoir in southeastern Kansas to determine whether a method can be developed for economic production. The method being studied involves the use of explosives to production. The method being studied involves the use of explosives to rubblize the formation, followed by solvent injection. Introduction There is widespread interest within the petroleum industry and state and federal governments concerning the large, heavy crude-oil resource in the United States. This interest has been stimulated by a decrease in the growth rate of the nation's proved crude-oil reserve, a forecast of increasing demand for domestic crude oil, and recent advancements in technology, particularly thermal methods of oil recovery. The heavy-oil reservoirs have received much attention because ofrecent increases in heavy-oil production from thermal-recovery operations,the existence of more than 2,000 known heavy-oil reservoirs, andthe high percentage of oil originally in place. Tar sands have been defined as oil-, bitumen-, asphalt-, tar-, or petroleum-impregnated rock from which little hydrocarbon material is recoverable by conventional crude-oil production techniques. Several rock types as well as petroleum materials are included in the term "tar sands." The rocks may range from consolidated and unconsolidated sandstone to shale, dolomite, limestone, and conglomerate. The hydrocarbons range from those difficult to soften in boiling water to those that ooze slowly from an outcrop on a warm day. In this paper, heavy oil is defined as oil having a gravity of 25 paper, heavy oil is defined as oil having a gravity of 25 degrees API or lower. The production potential for oil from U.S. heavy-oil deposits is poorly defined. Neither industry nor government has made a comprehensive and conclusive examination of the physical extent and economic possibilities of such deposits. Ref. 2 describes 546 occurrences of oilimpregnated sands and 383 shallow oil fields. Reserve figures, however, are available for only a few deposits. Only a few of the large deposits in California and Utah have been surveyed carefully enough to make the reserve figures meaningful; accurate volume figures for the remaining deposits are not available. Forty-two counties in Kansas, Missouri, and Oklahoma contain 40 percent of the recognized heavy-oil deposits. Much of this is fairly shallow (less than 500 ft) and could be mined; however, because of costs and environmental considerations, research must be initiated for the economical recovery of this crude by in-situ methods. Statistics on cumulative oil production are available on most of the productive heavy-oil reservoirs. A breakdown of heavy crude-oil resources in the U.S. indicates a proved reserve of 5.2 billion bbl with an oil resource of 106.8 billion bbl this resource is classified at 51.3 billion bbl of 20 degree to 25 degree API gravity and 55.5 billion bbl of crude lower than 20 degree API gravity. These figures do not include those oil-impregnated rocks that are known but from which no crude has been recovered. It is estimated that the total amount of heavy oil in the U.S. would be in excess of 150 billion bbl of oil in place if deposits were included such as those in western Missouri, eastern Kansas, northeastern Oklahoma, and other reservoirs that have no reported individual oil-production statistics. The geographical location of U.S. heavy-oil accumulations is shown in Fig. 1. JPT P. 105