The Jurassic Sedimentary Systerm And Reservoir Formation Potential Research In Longdong Area

Fuxian formation and Yan10～Yan6oil formation are the major oil producing zone of Longdong area in Odors basin. They are river and meandering delta sedimentary and are ultra-low porosity-low porosity and ultra-low permeability-low permeability reservoir. Geology, drilling, well logging, seismic data and so on were used in the study. On the basic of the theory of sequence stratigraphy, reservoir sedimentology, geophysical logging, the reserch was multi-disciplinary and integrated systematic analyed. We studyed on the sequence stratigraphy, source, reservoir, pre-Jurassic paleogeomorphological feature of research area and reservoir feature. At the same time, we divided accumulation model in research are.There are some main results and understanding:1. The palaogeomorphology was divided into erode-valley, ancient-upland, ancient uplift slope band, ancient terrace and mound; There are four ancient rivers:the first of Ganshan, the second of Qingxi, the third of Heqi and Qinghe; three ancient-upland: Yanwu, Jiyuan and Ziwuling ancient-upland. Six mounds and terraces.2. The structue maturity and component maturity are poor. Moreover, The direction of provenance are north and northwest, south and southwest. The Fuxian formation and Yan10～Yan6formations of Jurassic are river-meandering river delta deposits from below to above. And Fuxian Group and YanlO formation are the braid river sedimentary reservoir, Yan9formation and other formations which is above Yan9gradually become meandering river delta reservoir.3. The geological condition and factors of oil reservoir formation in research area are source rocks, hydrocarbon migration, reservoir seal assemblage and reservoir formation. The types of reservoir in area are devided into lithologic reservoir which is more in research area and complex reservoir which is distributed in north of area.4. According to Structure, sedimentary facies, reservoir characteristics and so on in the study area, we summarized that there are four oil reservoir formation models, mound model, uplift model, slope model and upland model.