Research On Characterization Of Single Sand Body Architecture Of Deep-water Gravity Flow In The Ban15 Area, Qingcheng Oilfield

The Chang 7 oil formation in the Qingcheng oilfield is a shale stratum with high exploration and development potential in the Ordos Basin of China.There is a large difference in production capacity for horizontal well because of the strong heterogeneity in the distribution of reservoir sand bodies.Taking the Chang 7 oil formation in the Ban15 area of the Qingcheng Oilfield as an example in this paper,Core,logging(vertical and horizontal well data)and seismic data were used to conduct a fine subdivision of single layer and achieve the architecture characterization of single sand body of sublacustrine fans in study area.Major achievements and insights were obtained:(1)Sublacustrine fan deposits were developed at the end of the slope belt and the end of the lacustrine basin in the Chang 7 oil formation in the study area.There are two types of single sand bodies: lobe and slump.Single lobe includes three types of sedimentary microfacies: channel,lobe main body and lobe margin.Single lobe can be divided into two shapes: tongue-shaped(aspect ratio >1.3,thickness between 1.5–3.8 m)and lobe-shaped(aspect ratio <1.3,thickness between 1.4–4 m).Single lobe has two types of vertical superposition patterns: stacking and isolated stacking.Single lobe has three types of lateral contact patterns: lobe-to-lobe,margin-to-margin,and mudstone barrier.Single slump is isolated lens-shaped body(width between 800–3000 m and thickness between 1–3.7 m).(2)Single sand body architecture is controlled by depositional bedform of basin and provenance distance.Finger-shaped lobe complex is developed at the end of the slope belt with relatively steep slope.Fan-shaped lobe complex is developed at the proximal end of the lacustrine basin with relatively flat slope and relatively distant provenance distance.Isolated lens-shaped slump is developed at the distal end of the lacustrine basin with distant provenance distance.