Prediction of subtle reservoir in the first and the second members of Shahejie formation in the southern transition zone,Huanxiling oilfield

According to the theory of sequence stratigraphy,and on the basis of data of core,well logging and borehole logging, it is set up the high-resolution sequence stratigraphic framework at the study area,in which can be divided into 2 long-term stratigraphic cycles,8 intermediate-term cycles and 20 short-term cycles.It is also analyzed the distribution of sand bodies and the sedimentary facies of each intermediate -term stratigraphic cycle.Based on the characteristics of strata sequence and sedimentary,the favorable subtle reservoirs are predicted.It is suggested that subtle reservoirs are favorable in the south of Well J128,the east of Well Jialing6 and among Well S203,Well J110 and Well J310.On the connection with the study on the characteristics of fault and sand body,i the result shows that the exploration targets should focus on the structural--lithological reservoirs in the thrown side of fault and the sand pinchout reservoirs during the period of lowstand systems tract (LST).