Experimental Study of Oil Displacement by the Bio-enzyme at the Third Type Reservoirs of Sabei Blocks

Sabei blocks are currently in the development stage with ultra-high water-cut. The remaining oil distributes scatteredly and quite a part scattered in the third type reservoirs where exists some problems such as poor producing capacity and water injection capacity, low productivity, fast rising rate of water-cut, and so on. The Bio-enzyme is a kind of chemical agent produced by microbial technology. It has the high capability of releasing hydrocarbon from the surface of reservoir rock particles, and can change the wettability of reservoir rocks and reduce the interfacial tension, thereby to reduce the flow resistance of oil in the reservoir pores and release the crude oil from the surface of the rock particles. The lab experiments in cores by bio-enzyme solution show that this agent can increase the recovery rate by 5.0% and reduce the injection pressure by 40%. The field test results showed that the bio-enzyme can improve the physical properties of underground oil, decrease the injection pressure of water wells, increase the injection volume, improve the injection profile and establish a good injection-production drive system. The oil well production increased significantly and the composite declining rate slows down at the same time.