A composite technology of in-depth stepwise channeling blocking and emulsifying viscosity reduction for heavy-oil steam huff and puff

To deal with serious steam channeling which occurs after several cycles of steam soaking in heavy oil reservoirs, emulsifying viscosity reduction technology was adopted, and consequently the recovery factor is increased significantly.To overcome the restriction and deficiency of single channeling blocking or emulsifying viscosity reduction technology, a composite technology of in-depth stepwise channeling blocking and emulsifying viscosity reduction for heavy-oil steam huff and puff was developed.The channeling blocking agent with different temperature resisting capacities and the emulsifying viscosity reducer with high-efficiency viscosity reducing effect were selected by means of laboratory experiments and physical simulation experiments.Then, the in-depth stepwise channeling blocking system was determined for the zones near the wellbore and far from the wellbore and that between them.It is shown from laboratory experiments that the plugging rate of stepwise channeling blocking system is higher than 99% and the viscosity reducing rate of emulsifying viscosity reduction system is higher than 95%.Its successful application in field demonstrates strongly its validity in heavy oil development improvement.It provides the theoretical basis and technical support for enhanced recovery of similar heavy oil reservoirs.