Deep Offshore Oilfield Flooding Technology

Chinese onshore oil field water flooding recovery levels are generally low, generally less than 50%,is one of the important reasons for restricting water flooding recovery to improve the sweep efficiency of water flooding is low. This is because the reservoir has complex structure,heterogeneity in different extent, promote the piston can not uniform forward water, leading to localwater channeling phenomenon, so that the production well soon see water and produce a large amount of water. Produced a large amount of water from water channeling and trench effect,reservoir heterogeneity are important reasons of water flooding during the early breakthrough.According to the statistics obtained 25 main oilfields in China: to improve the sweep efficiency of the injected water is an important direction to improve the development effect of water flooding.Because the formation of plane heterogeneity, vertical permeability variation coefficient is largerand the influence of cracks, the use of a lower degree of reservoir. At the late stage of oilfield water flooding development, single well water cut rises above 98%, often lose mining economic value, and the formation is still a lot of unused reservoir or the use of a lower degree of existing reservoir. For water injection development oil field, the heterogeneity of reservoir caused by injected water along the high permeability layer onrush, greatly reducing the sweep efficiency of injected water,restricted to enhance oil recovery. Obtained from field experience, the main reason of water flooding oil recovery of low permeability difference is: large, injected water channeling along the high permeability layer, oil-water viscosity ratio caused by fingering, complicated pore structure and rock surface properties make oil retention in the capillary etc.. How through effective plugging high permeability thief layer, in order to improve the reservoir heterogeneity; changing the subsequentinjection of fluid flow, in order to improve the flooding swept volume agent; adjust the displacement fluid mobility ratio, improve oil displacement efficiency. The resulting profile control and water shutoff technology.