| There are four types of structural belts favorable for hydrocarbon accumulation, which include the foreland belts,the central uplift belts, the sag anticline belts, and the slope belts, in the petroliferous basins, northwestern China. The foreland belt can be divided into the foreland uplift, the foreland thrust fault and the foreland thrust front subbelts. These structural belts dominated hydrocarbon migration and accumulation and resulted in different multiple areas of hydrocarbon accumulation in longitudinal superposition and lateral continuance. The foreland belts are mainly distributed in the southwestern
and the northern margins of Tarim Basin,the northwestern and the southern margins of Junggar Basin, the northern margin
of Turpan-Hami Basin,the southern margin of Jiuquan Basin and the northern margin of Qaidam Basin. The central upliftbelts are distributed only in Tarim Basin and Junggar Basin. The sag anticline belts, for some typical examples, include the Yingnan anticline belt in the middle Yengisu Sag in Tarim Basin, the Donghe-sandstone unconformity overlapping-pinching out belt in Mangar Sag in Tarim basin, and the Moxi faulted nose belt in Moqu Depression in Junggar Basin, and others.The slope belts are represented by the Hongliuquan slope belt in Qaidam Basin;where it is composed of stratigraphic unconformity traps and stratigraphic overlapping traps as multiple structural styles. |
