Analysis On Depositional Facies And Heterogeneity Of The Chang2 Reservoir In Sai 5, Sai 431 Region Of Pingqiao Area, Ordos Basin

The fine compartmentalized and parallelled of layers, paleocurrent and source direction,depositional systems and facies , reservoir heterogeneity of the Chang 2 Members of Yanchang Formation, Upper Triassic in Sai5,Sai431 region, Pingqiao area of Ansai Oilfield in Ordos basin are discussed, and integrately classified and estimated of reservoir are revealed in this paper, based on field work of geological survey and measurements of outcrops in the peripheral area of the Ordos basin, observation and description of 12 cores, analysis of drilling and logging data, observation and identification of thin-sections by point counting, measurement of light and heavy minerals in sandstones, Many new theories and technological methods related to High-resolution sequence stratigaphy, sedimentology, lithofacies and paleogeography, petroleum geology, borehole geophysics are used in the paper.By combining the high-resolution sequence stratigaphy theory and the traditional cycle-thickness method for the first time,studied the sides of the fine compartmentalized and parallelled of layers of Chang2 in the studying area, truely founded the building block of the aim sequence in the study area.Paleocurrent and source direction research result suggests that major paleocurrent direction was from the northeast to southwest during the Chang 2 Member of Yanchang Formation, Upper Triassic deposited. Five sedmentary microfacies of distributary channel,natural levee,bar point,crevasse splay and depression between channels was identified by using the methods of core facies and logging facies analysis in Chang2 members, the distributary channel deposits is the main reservoir bodies in it.Chose shale content, effective thickness, physical property, oil saturation and integrately estimated and classified the reservoir by using methods of clustering analysis in the studying area. It also predicted the favorable reservoir position to be explored in this area. The results laid a solid foundation for reservoir geologic modeling, numerical value simulating in the late development phase of oil field,and Provided a mass of essential quantitative data and geological basis,also play an important theoretics and practiceal role in the research of the prospected and exploitation of the Chang2 reservoir of the Yanchang formation in Sai5,Sai431 region of Pingqiao area.