Abstract:

Jinma-Yazihe area is located at the junction of Longmenshan fold-thrust belt and Sichuan basin. Based on the 3D seismic data, the characteristics of faults and the process of tectonic evolution are analyzed. The Bailuchang fault developed in the lower wall of Guankou fault can be regarded as its pre-existing fault, and the formed structural wedge causes local thickening of the lower wall. The shrinkage degree of the Guankou fault in the southeast direction is becoming smaller and smaller, which generally shows the vertical superimposed structural combination of stratified slip faults controlled by double slip layers. Pengxian fault is composed of several faults with a large fault distance in the middle part, which can be used as an indication of local tectonic stress transformation or concentration. The main faults in the Jinma-Yazihe area started in the early Indosinian period, continued to deform in the late Indosinian movement and strongly moved in the Yanshanian period. The Guankou and Pengxian faults thrusted strongly in the Yanshanian period, and continued to deform from the Himalayan to the neotectonic period, resulting in strike-slip and affecting the surface. Structural activities are closely related to hydrocarbon accumulation and contribute to the formation of structural traps, reservoir transformation, hydrocarbon migration and accumulation.

Key words: Jinma-Yazihe, Guankou fault, Pengxian fault, tectonic evolution, hydrocarbon accumulation