Control factors on tight sandstone reservoirs below source rocks in the Rangzijing slope zone of southern Songliao Basin, East China

Based on the analysis of reservoir characteristics, this paper studies on the control factors on quality of the tight sandstone reservoirs in Fuyu oil layer below source rocks in Rangzijing slope zone in the Southern Songliao Basin from 5 aspects, i.e. base level cycle, deposition, diagenesis, tectonic activity and CO2 filling, so as to identify the sweet spots in the reservoirs. The following results are obtained: (1) base level cycle and deposition condition control the relation of source rocks and reservoirs, stacking pattern of reservoirs and original property of reservoirs; (2) compaction is the main factor making the reservoirs tight, and cementation exacerbates the tightness; (3) the secondary pores produced by organic acids migrating downward into reservoirs improve the reservoir quality to some extent; (4) tectonic activity plays a positive role in improvement of reservoir quality in three levels, and (5) CO2 filling can improve the percolation of local reservoirs, but it is adverse for the formation of effective reservoirs. In the study area, the formation of high-quality tight sandstone reservoirs is controlled by the coupling of base level cycle, main sedimentary facies, dominant corrosion zone and tectonic uplifting area.