Reservoir Forming Mode and Target Optimization of Tight Gas Reservoir in SZJ Sub-Sag of Changling Depression

Abstract

In order to explore the natural gas replacement resources in Jilin exploration area, the SZJ sag in Changling fault depression of Songliao basin, which has the most significant resource potential in the exploration area, was studied by using fine intelligent structural interpretation technology, low well control velocity field modeling technology, and characteristic parameter inversion technology. The distribution scale of hydrocarbon source rocks and reservoirs of Shahezi Formation in SZJ sag and the overall gas bearing capacity of the sag are predicted. The results show that the superimposition area of high-quality hydrocarbon source rocks in the study area is about 356 km2, with a cumulative thickness of 100 - 300 m. The superimposition area of favorable reservoir distribution in Shahezi Formation is 316 km2, with a cumulative thickness of 56 - 125 m. According to the analysis of the source-reservoir configuration relationship in the study area, the tight gas reservoir formation model of Shahezi Formation has three types: fault-nose type, updip pinch-out type and lateral docking type; The three favorable target areas for high yield and enrichment of gasaccumulation A, B and C are all located in the fault anticlinal trap range of the central fault zone of the T41 reflector in the depression, and the optimized areas have been confirmed by drilling. The tight gas reservoir resources in the deep depression of Changling fault depression in Songliao basin have great potential.