CHARACTERISTICS OF DIAGENETIC EVOLUTION OF CHANG 2 SANDSTONES (UPPER TRIASSIC) IN THE WESTERN ORDOS BASIN
鄂尔多斯盆地西部三叠系长2油层组砂岩成岩演化特征

Chang 2 sandstones of Yanchang formation (upper Triassic) in Yanchi-Jiyuan area, southwest Ordos basin, are a set of distributary channel and mouth bar sandstone bodies formed in delta front facies, and mainly composed of lithic feldspathic sandstone and feldspathic sandstone, of which the average content of quartz , feldspar and lithic fragments accounts for 32.6%, 38.9% and 8.0%, respectively. Metamorphic and igneous rock fragments are main lithic constitutes, accounting for 87.5% of the total fragments. ...