Differential Hydrocarbon Accumulation Controlled by Structural Styles along the Southern and Northern Tianshan Thrust Belt

Abstract:The Kuqa and the Southern Junggar foreland thrust belts, which lie to the southern and northern Tianshan, respectively, were formed under a strong compressional tectonic setting. Due to the differential propagation and deformation under the control of the décollement horizon, the structural deformation styles differ in the Kuqa and Southern Junggar thrust belts. Imbricated stacking is developed in the Kuqa thrust belt, forming a piggyback imbricated pattern of faulted anticline and fault‐block structural assemblage dominated by salt structures. In contrast, wedge‐shaped thrusts are developed in Southern Junggar, mainly forming vertical laminated patterns of multi‐wedge‐structure stacks strongly influenced by the décollement horizons. The different deformation patterns and structural styles of the north and south of Tian Shan control the contrasting characteristics of hydrocarbon accumulation in the foreland thrust belts of the Kuqa and the Southern Junggar thrust belts, including the variance in the hydrocarbon trap types, pathway systems and hydrocarbon‐bearing horizons. Proven by the hydrocarbon accumulation research and exploration achievements, recent exploration targets should focus on sub‐salt piggyback imbricated structural patterns in the Kuqa and the deep laminated patterns in the Southern Junggar thrust belt.