Polymer Flooding for Middle and Low Permeability Sandstone Reservoirs

Daqing Oilfield is a heterogeneous sandstone oilfield with multi-layers. Polymer flooding in primary oil layers has obtained significant technological and economic effects. As the recoverable reserves of primary oil layers decline yearly, secondary oil layers have become the focus of industrialized polymer flooding since 2003. Compared with the primary layers in Daqing Oilfield, secondary layers are of thinner thickness, lower permeability, narrowly-developed channel sands and poor continuity of sand bodies. There are four lower aspects and two imbalances in the dynamic performance of polymer flooding in secondary layers. Due to the geological properties and recovery performances of secondary layers, measures are taken to further enhance their recovery factors. Polymer flooding objectives are carefully selected, layers are carefully divided, well spacing between injectors and producers is shortened, and separated-layer polymer injections are widely utilized. In consequence, better development has been obtained.