A Study On Sedimentary Characteristics Of Sanjianfang Formation Of Shanshan Oil Field

Based on the theories of high-resolution sequence straitgraphy, sedimentary petrology, reservoir geology and logging geology, this article finishes the study of fine reservoir description of Sanjianfang formation of Shanshan oil field, sedimentary characteristics, log facies pattern, reservoir physical properties and anisotropy by the analysis of comprehensive core observation, well logging, and the field performance data.Under the direction of high-resolution sequence straitgraphy, this thesis summarizes the important marker beds which are the basis of dividing and comparing strata in the study zone. According to the principles of sedimentary cycle and beds control,the reservoir sedimentary unit is divided into 2 oil reservoir groups(Long-term base-level cyclic sequences),5 sand groups(Metaphase base-level cyclic sequences),18 substratum(Short-term base-level cyclicsequences) and 38 single layers in the study zone. On the basis of the further study of regional geological setting, sedimentary characteristics, log facies analysis and the predecessors'research fruits, the article identifies the facies of Sanjianfang formation are fan-delta facies and braided river delta facies, which can be divided into 4 kinds of subfacies and 15 kinds of microfacies.According to the research of sedimentary and structural features in Sanjianfang formation, the paper initially summarizes the sedimentary facies' distribution regularity, determines the position of lakeshoreline, ascertains source area and points out the main reservoirs favorable for remaining- oil are sand bodies of underwater distributary channel deposits, channel bar and sheet sand bodies by combining with areal distribution of sand bodies, physical characteristics, anisotropy, sedimentary micro facies characteristics and sedimentary microfacies' distribution regularity.