Sedimentary Facies of Upper Triassic in Western Sichuan Basin

Depositional settings of the Upper Triassic of western Sichuan Basin are favorable for the formation of giant deep basin gas traps. Based on microfacies of cores and sandbody texture as well as facies analysis, the main types of sedimentary facies in the Upper Triassic sequence of western Sichuan Basin have been identified. They include fluvial-dominated delta, embayment, lake, and alluvial fan. The delta constitutes the dominated reservoir in the deep basin. Based on correlation of sedimentary provenance, sandbody geometry, and environmental parameter, the depositional systems and sedimentary facies in each members of the Upper Triassic sequences are described in detail.