Review of Practical Experience of Polymer Flooding at Daqing

This paper describes successful practices applied during polymer flooding at Daqing that will be of considerable value to future chemical floods, both in China and elsewhere. On the basis of laboratory findings, new concepts have been developed that expand conventional ideas concerning favorable conditions for mobility improvement by polymer flooding. Particular advances integrate reservoir-engineering approaches and technology that is basic for successful application of polymer flooding. These include the following: (1) Proper consideration must be given to the permeability contrast among the oil zones and to interwell continuity involving the optimum combination of oil strata during flooding and well-pattem design, respectively; (2) Higher polymer molecular weights, a broader range of polymer molecular weights, and higher polymer concentrations are desirable in the injected slugs; (3) The entire polymer-flooding process should be characterized in five stages-with its dynamic behavior distinguished by water-cut changes; (4) Additional techniques should be considered, such as dynamic monitoring using well logging, well testing, and tracers; effective techniques are also needed for surface mixing, injection facilities, oil production, and produced-water treatment; and (5) Continuous innovation must be a priority during polymer flooding.