Distribution Characteristic and Genetic Mechanism of Hydrocarbon Traps of the Terrestrial Clastic Rock in Sichuan Basin

Based on the statistical analysis of terrestrial clastic hydrocarbon fields in Sichuan basin, this study concludes that the traps in Sichuan basin can be classified into three types: structural trap, lithologic trap, and structural-lithologic compound trap. The type of structural trap is back thrusting block one. Lithologic trap is defined chiefly by superimposition of multi-layer sandstone lens. Traps of the terrestrial clastic hydrocarbon fields in Sichuan basin can be divided from west to east into three structural belts: pop-up trap belt, structural-lithologic compound trap belt, and lithologic trap belt. The pattern of such kind attributed to zoning of the structural features of Sichuan basin. From Majiaoba-Tongjichang-Shuangshi faulting zone in the Longmengshan thrusting zone to northeastern Sichuan, four belts can be recognized: thrust belt, depression belt, uplift belt and steep folding belt. Besides, trap distribution manifests distinct segmentation from south to north, the mode of which, in the same way, depends on deformation and evolvement differences of structures.