Abstract: The research strategy being divided into three-step runs for EOR is proposed. The first step is the study of distribution type and exploitation technology of “megascopic scale” unswept remaining oil;; the second step is the study of distribution type and exploitation technology of “macroscopic scale” unswept remaining oil;; the third step is, on the basis of these two steps,to study the way of improving oil displacement efficiency in swept areas. Ten technologies for developing three enriched areas of “Megascopic scale” unswept remaining oil are presented. They are:①technologies for producing the unswept remaining oil at the top of the positive rhythm reservoirs with high viscous oil,, including horizontal sidetracks, cyclic waterflooding, water/ gas alternation, gel/ propellant/ acid-fracturing treatment;; ②)technologies for producing the unswept remaining oil caused by side and corner parts in oil reservoirs, including reversed and vertical fracture fracturing with reversed direction and orientation, horizontal sidetracks, horizontal well; ③technologies for producing the unswept remaining oil formed by non-proportional development of each substratum with different petrophysical properties, including dewnhole measures (water shutoff, profile control, and stimulation of low permeability, etc.), infill well and changing direction of filtration flow.

Key words: waterfooding, reservoir, remaining, exploitation, technology, horizontal well