• 责任者：Cui Jingwei (Research Institute of Petroleum Exploration and Development ; PetroChina ; Beijing 100083 ; China) ; Zhu Rukai
• 刊名：Acta Petrolei Sinica
• 出版年：2013
• 卷期：34(5)
• 关键词：致密砂层 ; tight sands ; 鄂尔多斯盆地 ; Ordos Basin
• 页码：p.877-882
• 图表：6 illus., 1 table, 20 refs.
• 分类号：1003
• issnNo：ISSN0253-2697
• isbnNo：CN11-2128/TE

     The tight oil exploration has made a great breakthrough in USA （Eagle Ford, West Bay Basin and Bakken, Willis Basin） and been in the spotlight worldwide for its huge potential prospect. China has a wide distribution of tight sandstones. Through care- ful observations of core samples from Chang-7 layers of the Triassic Yanchang Formation from some dozens of wells in the Ordos Ba- sin, we come to realize that obviously oily heterogeneity exists in these tight sandstones, especially in intrabed single sand body. Dif ferent oily sandstone samples were collected from the Triassic Yanchang Formation for comparison study and analytical techniques in- cluding thin section, chloroform bitumen, field emission SEM, micro-CT, high pressure Hg injection, N2 adsorption and sandstone XRD were performed on them. Diagenetic features, oiliness, microspores and throats, pore size distributions, specific surface areas and mineral compositions of these tight sandstones were obtained. The results show that the heterogeneity of reservoirs may result from calcareous cementation and tight sandstones tend to mainly develop nano-throats （diameter~l/~m）. According to plates of the residual oil content versus the average pore diameter of mesopores and the oil content versus porosity, 15nm of the average aperture of mesopores and 2% of porosity may be regarded as lower oily limits for tight sandstones, and these criteria can provide a reliable reference for exploration target selection and resource assessment of the unconventional tight oil.