Sedimentary Facies Study Of Shahejie Formation Eogene In The West Qudi Oil Field

Huimin depression is important oil and gas bearing basin in Bohai Bay Basin. Sedimentary facies and distribution of sand bodies of the Shahejie formation in the west Qudi oil field, that is located in the south slope of Huimin depression, were systematieally studied. After many years of exploration and research, many oil and gas fields based on structural reservoir have been diseovered. In recent years, with many sequent discoveriesof elusive reservoir, such as stratigraphic reservoir and ancient buried hill hydrocarbon reservoir, we believe there is still much potential for exploration in Qudi oil field, and these discoveries will exert a profound enfluence on the output of reserves.Based on the comprehensive research of basic characteristics, formation and evolution in Qudi oil field, from studying some data of well drilling, logging and seismic, the typical well depending on the characteristics of fault-block has been set up, and 200 wells' stratum in the study area have been divided and compared. Shahejie formation has been divided into Es1, Es2, Es3 Es4S, Es4Z, Es4X.Based on the study of facies indicators of sedimentary structure, Biological characteristics and geophysical signature, 4 depositional system including alluvial fan , fluvial, delta, lacustrine developed in Shahejie formation, and the mid-fan,end-fan, mainly developed during the depositional Period of Es4X, meandering river- Miniature alluvial fan mainly developed during the depositional Period of Es4S- Es4Z,delta front developed during the depositional Period of Es3- Es2, shallow lake mainly developed during the depositional Period of Es1.From analyses of cathodeluminescence, light mineral, heavy mineral and cuttings, the provenance system that mainly comes from west Shandong uplift and mainly direction is south-east trending has been comfirmed. On the basis of provenance system, under the guidance of Petroleum Geology and Sedimentology theory, according to the sand content chorisopleth and the distribution of sand thickness, lithofacies paleogeography maps of Es1-Es4(including ESsS,Es4Z,Es4X) have been drawn, and sedimentary facies, unfold characters of sandstones have been detailly study.