Abstract:

Growth thrusts that were widespread in Tertiary deposits of Gasi fault subsidence in Qaidam Basin controlled the structural framework of the three main kinds of structures,and formed growth anticlines,drag anticlines and fault nozes.The tectonic evolution pro-cess could be divided into formation stage,growth stage and stagnation stage.As for the source rocks,that in the footwall of the thrust are characterized by high maturity and transformation ratio of organic matter,high oil saturation and excess pore-fluid pressures.The growth thrusts might act as the passage path for hydrocarbon migration.The growth structural traps derived from the thrusts generally have following favourable conditions:1.close to oil source,especially the growth anticlines which usually form hydrocarbon pools of lower formation generated-upper formation reserved type;2.long time and multi-stage of hydrocarbon supply due to early formed traps;3.abundance of oil source and multi-layer of oil supply.