Evaluation of Thin Inter-Bedded Reservoir Connectivity with Different Single Sand Body Superimposed Pattern

In the development of oil and gas fields, the corresponding relationship between thin interbedded sand bodies is complicated due to the small thickness of sand bodies, the concentrated distribution of sand and mudstone and the strong similarity of log curves, so the calculation of connectivity rate is prone to human error. Based on the reservoir configuration, this paper calculates the sand body connectivity for different single sand body superposition types. Among them, the lateral superposition type is easy to be confused with the longitudinal superposition type, and the difference in connectivity between them is nearly 24%. Therefore, it is necessary to conduct reservoir configuration analysis before reservoir connectivity evaluation. On this basis, the superposition types of single sand bodies of well group Z-11x in Z block are analyzed. From deep to shallow in this area, three types of lateral superposition, lateral separation and vertical superposition are developed successively. The recalculation connectivity rate is 74.7%, which is 14.8% lower than that before the analysis of reservoir configuration. According to the reservoir configuration and the relationship between single sand bodies, it is suggested to adjust the injection-production horizon in block Z and take some production measures such as fracturing.