Theory and practice of redevelopment in mature oilfield-taking Block Xinhai 27 of Haiwaihe oilfield as an example

The mature oilfield is a one that underwent at least one traditional primary oil recovery or is undergoing one primary oil recovery of bad effect,and is hard to achieve the calibra- ting recovery ratio or is potential to further enhance the re- covery ratio.The redevelopment strategy can be introduced to further enhance the recovery ration of old oilfield by alte- ring and/or recombining well type,changing displacing me- dium and mode to solve the inadaptation of the current layer series of development,well pattern,well type.or exploita- tion mode.The basis for executing the redevelopment is the accurate reservoir characterization and potential evaluation with the aim to improve the recovery factor.The key to suc- cess of the redevelopment is to introduce,apply and popular- ize new processes and technologies.The redevelopment mod- els include the optimal water and/or steam injection,the pat- tern modification and the conversion of exploitation pattern. Satisfactory effects have been achieved after the executing the redevelopment.