Oil recovery by steam drive - by maintaining the cumulative quality of the injected steam within predetermined limits

摘要

In the recovery of hydrocarbons from subterranean formations by means of steam injection techniques initiated by the injection of high-quality (70-50%) steam, the improvement comprises continuing the steam drive by the injection of low-quality steam or water such that the cumulative quality of the injected steam is reduced to and maintained at 35-45 (pref. 35-42, esp. 40)%. Used partic. with relatively thick hydrocarbon-contg. formations having >=30 ft. of hydrocarbon-contg. intervals. Heat utilisation is optimised and sweep efficiency is improved.