New hydrocarbon exploration areas in footwall covered structures in northwestern margin of Junggar Basin

The fold-and-thrust belt in the northwestern margin of the Junggar Basin is composed of the northern monocline belt, the middle syncline belt, the Ke-Wu thrust belt, and the frontal slope belt, and is divided into the upper and lower structural layers in vertical. The upper structural layer precedes the lower one in terms of thrust sequence. Inferred from the restoration of unconformities, the motion of thrust faults started in late Triassic, activated in succession in Jurassic, and stopped in Cretaceous. The footwall venture exploration should aim at “cap brim” traps, especially in the triangular region, where the Dazhuluogou tear fault and Ke-Wu thrust belt intersect and the exploration horizon imbeds moderately, and then aim at the deep anticline traps in duplex structures when obtaining the essential data of deep geology and the velocity data.