Study On Recognition Of Thief Zone By Injection-production Data

At present,water flooding development is one of the most important approach to control the production of oil and gas in the majority of oilfields.Thief zone is the relatively high permeability stratigraphic unit,which come into being after long-term water flooding.The existence of thief zone will lead to unstable displacement and inefficient water circulation,which destroyed the reservoir development effect and increased the injection and processing cost of the injection fluid.Therefore,how to identify the thief zone effectively and which measures should be taken to deal with them have become imperative to improve oil recovery.However,the existing identification system is incomplete,for example,the thief zones recognition factor is not comprehensive.Therefore,this paper will build a comprehensive identification method of theif zone by using the static data and production performance data.This method can determine the injection well group,the direction and the horizon.Evaluation index system is established by using the geological data and production performance data,which reflects the dynamic response characteristics of the theif zone.At first,the method can identify wells of theif zone using principal component analysis.At the same time,physical parameters of thief zones are obtained by interpolation method with typical well’s quantitative results.Then,the method can determine the developmental direction of the theif zone by gray relational analysis.Finally,the method can identify developmental horizons of theif zone by the improved fuzzy comprehensive evaluation method.The method enhances the understanding of the reservoir.The result provides a theoretical foundation and basis for the profile control and water shut cut and other measures.This method is helpful to improve the development of oilfield and oil recovery.