Soft-sediment Deformation Structures and Sand Body Architecture in the Chang 6 Oil Member of the Upper Triassic Yanchang Formation, Southwestern Ordos Basin, China ; Estructuras de deformación de sedimentos blandos y arquitectura de cuerpos de arena en el miembro de petróleo Chang 6 de la formación Yanchang del Triásico Superior, al suroeste de la cuenca Ordos de China

Soft-sediment deformation (SSD) structures of the Upper Triassic Yanchang Formation are laterally widespread in the Ordos Basin. In the Huachi-Qingyang (H-Q) area of the Ordos Basin, the Chang6 oil member of the Upper Triassic Yanchang Formation is among the most significant Mesozoic oil-bearing strata. It is characterized by the development of reservoir sand bodies. During the depositional evolution of the Chang6 oil member, SSD structures induced by paleo-seismic events developed in the H-Q area in the middle of the basin. The SSD structures developed in the sand bodies of the Chang6 oil member are mainly ball-and-pillow structures, fold structures, sand dikes, irregular convolute stratifications and synsedimentary faults. The architecture of the sand bodies resulted from paleo-seismic events and gravity slumping and mainly include two types of structures: 1) SSD structures driven by paleo-seismic events with normal sedimentation (delta front sand body) (SN-SSD) and 2) SSD structures driven by paleo-seismic events with turbidites (formed by delta-front slumping and re-distribution due to seismic action) (ST-SSD). As a consequence, genetic models of the sand bodies formed by different sedimentation processes are established. ; Las estructuras de deformación de sedimentos blandos de la Formación Yanchang del Triásico Superior están extendidas lateralmente en la cuenca Ordos. En el área Huachi-Qingyang de esta cuenca, el miembro de petróleo Chang 6 está entre los estratos petrolíferos más significativos del Mesozoico. Este se caracteriza por el desarrollo de cuerpos de arena en el yacimiento. Durante la evolución deposicional del miembro Chang 6, las estructuras de deformación de sedimentos blandos se desarrollaron en el área Huachi-Qingyang, en el medio de la cuenca, inducidas por eventos paleosísmicos. Las estructuras de deformación de sedimentos blandos que se desarrollaron en los cuerpos de arenas del miembro de petróleo Chang 6 son principalmente estructuras esféricas y acojinadas, ...