The Research On Sedimentary Microfacies And Reservoir Of Shahejie

The X oilfield lies to the north of X village in H county and the tectonic location is loc ated in western of South Dagang structural belt in Huanghua depression. Since the develop ment in August 1970, the composite water content is more than 90 percent, it has entered t he development stage of high water cut stage.The predecessor have conducted much wok about reservoir description, and have recognized underground structure system and reservoir characteristics to some extent, but they did not have a clear understanding of the underground sedimentary system, so that the problem that remaining oil recovery rate is difficult to improve,has not been solved. For the old oil fields of higher degree of exploration and development, it can’t meet the production requirements that only on the study of sedimentary system. Therefore the research on sedimentary microfacies is extremely important to oilfield development.This paper selects lower part of the Sha-1 Formation, Sha-2 Formation and Sha-3 Formation of the Shahejie Formation as target, according to "single well facies – well tie facies-plane facies" as the research line, and researches the types and plane distribution of sedimentary microfacies, and reservoir characteristics, with the core, logging, seismic and previous reservoir description data, Some conclusions are drawn as follows:1.The lower part of the Sha-1 Formation of X oilfield have developed several types of sedimentary facies including organic bank fulls, organic bank flank, shallow lake, semi-lake; The Sha-2 Formation have developed the channel of nearshore, the middle of channel of nearshore, sand sheet, shallow lake, semi-lake and deep lake; The Sha-3 Formation have developed the channel of infralittoral turbidite fan, the middle of channel, sand sheet and deep lake shale facies.2.Unlike the previous studies, the paper says Es22 layer mainly developed deep lake subfacies, thick sand Division for nearshore fan channel deposits; at the top of the Es3 section mainly developed deep lake phase and the fan is infralittoral turbidite fan instead of the nearshore fan for predecessors.3.There are two sets of reservoir in X oilfield: Es1 x bioclastic limestone reservoir and Es2 and Es3 sandstone reservoir. According to the distribution of well test results, the main oil production layer are Es1x33 layer, Es2 member and Es32 sub member of the top of Es3 member sandstone. The Es3 member, as oil source bed, generates hydrocarbon compound which migrated upward and accumulated in the sandstone of the top of Es3 member and Es2 member and bioclastic limestone of the bottom of Es1 submember, which is in accordance with the geological law of " The reservoir is in the upper and the source bed is in the lower".