Research And Application Of Deep Profile Control And Flooding Technology In Shinan 31 Oil Field

Shinan 31 Qingshuihe Formation reservoir is a structural lithologic reservoir with low porosity,low permeability,thin beds and edge water.After years of high efficiency development,it gradually exposes some development contradictions and makes it more difficult to stabilize production.In order to rationally develop reservoirs,improve development effect,strengthen basic research of reservoirs,control water cut rising speed,slow down decline,and deeply understand reservoir geological characteristics,it is necessary to carry out profile control test in Shinan oilfield to alleviate oil production on the basis of analyzing water breakthrough effect characteristics,water cut rising law and reservoir development contradiction.The contradiction between reservoir development and improvement of development results can achieve stable reservoir production.Firstly,the geological characteristics and development process of Qingshuihe Formation in Shinan 31 well area are studied.The results show that the dominant channel of water flow is mainly east-west.The analysis of overall profile control potential shows that the recovery degree is low and the profile control potential is great.Secondly,the properties of two kinds of profile control agents,namely organic chromium pre crosslinking gel and microsphere,were evaluated.The results showed that two kinds of profile control agents,organic chromium pre crosslinking gel and microsphere,had good temperature resistance,salt resistance,adaptability to formation and plugging ability.Thirdly,the principle of well selection for profile control wells is clarified,the method of determining profile control dosage and radius is established,and the method of determining injection pressure is given.Finally,the profile control results of 32 profile control wells from 2015 to 2017 show that the average injection pressure increases by 1.03 MPa,the apparent water absorption index decreases by 2.6 m3/MPa,and the cumulative oil production increases by 13123.7 t.Economic evaluation shows that the organic chromium pre crosslinking gel profile control technology has better economic performance,and the economic benefits of horizontal wells,high water cut oil wells and sandstone layers are better.Priority should be given to profile control and well selection...