CHARACTERISTICS OF VALLEY-SLOPE BREAK ZONE IN THE WESTERN CIRCLE OF THE BOZHONG DEPRESSION AND ITS CONTROL OVER RESERVOIR DISTRIBUTION

Based on the data of well logs,seismics,core and regional geology,the types and characteristics of valley-slope in the BZ3 area were studied in detail,with focus on analyzing the control effect of different type of slope-break zone over the depositional system under the base-level cycles.The favorable areas for hydrocarbon exploration were also predicted primarily in this paper.The results show that there are three types of valleys,i.e.U-shape,V-shape and W-shape valleys,and three slope-break zones,i.e.high,low and flexure ones in the BZ3 area.The delta-front facies developed on the terrace Ⅰ and the low-stand fan developed on the terrace Ⅱ are the favorable areas for reservoir development.