Research On Sedimentary Microfacies Of Fuyu Oil Layer And Its Relation With Oil Pool In South Songzhan

The region of South Songzhan is located in the northeast slope of Sanzhao Depression-Central Depression of Songliao. On the North is the Songzhan gas Fields, west is Shengping oil and gas field, east is Shangjia oilfield and the south is Yushulin oil field. The deep gas field of Xujiaweizi is discovered here. So, it shows that South Songzhan is an area with good oil prospect. However, the exploration of Fuyu oil layer is still relatively low, single well yield less hydrocarbon and the factors affecting the oil accumulation are blurred. Regional geological conditions, Fuyu reservoir sedimentary facies and the distribution of sand bodies, and the sedimentary characteristics which affect the hydrocarbon accumulation are very significant for the exploration and development of Fuyu oil layer.In this paper, combined with the regional background, applied sequence stratigraphy, sedimentology and petroleum geology, based on high-resolution seismic data, well logging, logging, core analysis, Fuyu oil layer was deeply divided into 7 thin layers, single-well sedimentary facies analyzed, the sedimentary facies patterns determined and the characteristics of sand body and microfacies distribution studied. According to the mechanism of Fuyu reservoir formation, we know the relationship between the distribution of oil and gas reservoir and the sedimentary microfacies and sand body. The main research results are as follows:1. Deeply divided Fuyu oil layer into 7 thin layers through stratigraphic classification and correlation.2. Determined that south Songzhan is mainly meandering river sedimentary system controlled by Baiquan-Qinggang sedimentary system in northeast, its manly micofacies are river channel, burst river channel, abandoned channel, crevasse splay, alluvial flat.3. The study on the distribution of micofacies, sand body shows that en bloc, has poor connectedness when Fuyu oil layer deposited. The average number of river channel in every layer is 7; the body river channel is North-South, which is narrow band, small river channel, controlling the oil accumulation reservoir.4. The research on the T₂ faults pointed out that T₂ faults is the direct pathway of oil migration in south Songzhan. The sand bodies of river channel and burst river channel are the main areas for oil accumulation and the favorable areas for oil exploration in the future.