Limitation of core data results in the inability to show the vertical variation of the diagenetic facies whereas log data continuously record all the physical properties of the penetrated layers ( Aysen et al., 2011 Cui et al., 2017 Lai et al., 2019 Zhou et al., 2019). The previous study of diagenetic facies mainly relied on relative core analysis, especially on data of thin section, SEM, and cathode luminescence reflecting microscopic features ( Lai et al., 2013 Qin et al., 2018). Diagenetic facies study focusing on the effects of diagenesis process on reservoir properties and pore configuration ( Ochoa, 2010 Cui et al., 2017 Lai et al., 2018) is to effectively help hydrocarbon exploration and development by determining the spatial distribution of high-quality reservoir to provide reliable evidence for reservoir prediction ( Maast et al., 2011 Meng et al., 2015 Li et al., 2019). Diagenetic facies including mineral constituents, cement, fabric, pores, and fractures, which reflects the current mineral composition and fabric features and is the genetic mark representing reservoir nature, type, and quality, is the result of sediments which underwent diagenesis and a period of diagenetic evolution ( Zou et al., 2008 Li et al., 2019 Li et al., 2020). Rapid quantitative evaluation of diagenesis based on diagenetic facies study is the most widely used now and will be the major methodology ( Jiang et al., 2014 Zhu et al., 2016 Cui Y et al., 2017). Continuous researches on diagenesis have made significant achievements in which multi-technological quantitative evaluation is used ( Hao et al., 2010 Guo et al., 2018 Qin et al., 2018 Xi et al., 2019). The actual exploration effect of the traditional method for the evaluation of tight sandstone reservoirs is poor, which is mainly because the fact that the reservoir physical parameters can not reflect the strong heterogeneity of tight sandstone reservoir ( Nian et al., 2016 Zhu et al., 2016 Zhou et al., 2019 Qiao et al., 2020). The evaluation and prediction of the tight sandstone reservoirs have been hotspots for the petroleum industry ( Guo et al., 2019 Ren et al., 2019 Xiao et al., 2019 Li et al., 2020). The quantitative identification of diagenetic facies based on logging information can provide reasonable results for the evolution of the tight sandstone reservoirs for a similar area in the Tarim Basin. Composite analysis of diagenetic facies, sedimentary facies, and porosity distribution shows that the favorable area of further exploration and development is east of Well SH903 and north of Well SH10. Interpretation of the log data from individual wells with “K nearest neighbor” algorithm concludes that top and base of the upper member of Kepingtage Formation are believed to have favorably diagenetic reservoirs mainly falling in Type V favorably diagenetic facies develop best in the lower member of Kepingtage Formation predominated by Types V and VI which mainly distribute in its top. Quantification of diagenesis influencing porosity suggests that sandstone densification is mainly controlled by compaction, cementation, and hydrocarbon charging (bitumen charging), and the reservoir properties are effectively improved by dissolution, based on which 6 types of diagenetic facies are classified. Cores of the tight sandstone reservoirs of Lower Silurian Kepingtage Formation in Shuntuoguole Low Uplift are studied with thin section observation, SEM, XRD, and mercury injection. In this study, we investigated the effects of diagenesis on the heterogeneity of tight sandstone deposits in similar sedimentary facies and established the relationship between the diagenetic facies and reservoir quality. How to evaluate tight sandstone reservoir is an urgent problem to be solved. The tight sandstone reservoirs of the Lower Silurian Kepingtage Formation are important exploratory targets for tight gas resources in the Shuntuoguole Low Uplift of Tarim Basin.
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