Shell Oil Company's Slocum Thermal Recovery Project is successfully recovering 19° API oil from the 500 foot deep Carrizo sand. In the eight years prior to initiation of steam injection, primary production recovered only 300,000 barrels of oil, or about 1 percent of the original oil-in-place. Three years of full scale operation have recovered 1.4 million barrels of oil, representing 4.7 percent of the original oil-in-place.
After pilot testing, injection was started into seven, 13-spot patterns in March 1967. To date, 13 additional patterns have been installed. The low injectivity of the oil sand precludes conventional water or steam drive processes; however, the underlying water layer provides a path for efficient heat communication and steam injection.
Among the problems encountered in this thermal operation are dehydration of complex emulsions, restricted hot well production performance, production of hydrogen sulfide gas, and production of organic solids.