Structural features, evolution and petroleum geological conditions of the Sunwu-Jiayin Basin in northern Heilongjiang province

The data of gravity and aeromagnetic surveys revealed that the depth of buried basement of the Suwu-Jiayin Basin was 0.1-2.5 km, and the basin could be divided into three depressions sandwiched in two uplifts with NE trend, which were named, in eastward order, the Sunwu Fault-Depression, the Maolanhe Rise, the Zhanhe Fault-Depression, the Furao Rise and the Jiayin Fault-Depression. The seismic data showed the basemental depth of the basin being 0.1-6.3 km, and sub-order tectonic units of the fault-depressions were divided further. The formation and evolution of the Suwu-Jiayin Basin seemed similar to the Songliao Basin, which went through four stages, namely, the pre-extensional stage, the faulting depression stage, the down-warping stage and withering stage. The source rocks in the Lower Crataceous Taoqihe Formation, the Upper Crataceous Yongaueun and Taipinglinehang formations were matured and the reservoir was good, which were main exploration layers in the basin. According to the evaluation of the petrole