High-resolution sequence stratigraphic correlation of fan deltas and distribution characteristics of sandbodies

Abstract：According to the core and well log data and lithologic and electric correlation, high-resolution sequence stratigraphic study has been conducted on the fan deltaic reservoirs in pay sets 4 to 8 of the Third Member of the Shahejie Formation in the Huzhuangji oilfield. The criteria for recognition of different orders of cycle boundaries and cycle types are established, and the studied section is divided into one long-term cycle and six medium-term cycles. The correlation principle and method of short-term stratigraphic cycles are determined and the framework of correlation of short-term cycles is established according to the controls of medium-term cycles on the deposition of sandbodies and relationship between the geomorphological change and types of short-term cycles parallel or perpendicular to the direction of the provenance. The distribution characteristics of sandbodies and reservoir properties in short-term cyclic sequences are notably different in different phases of a medium-term base-level cycle, which is the main cause responsible for serious reservoir interlayers or plane heterogeneities. It should be taken into account when the sequences of strata which are to be exploited are distinguished in detail.