ABOUT THE INFLUENCE OF GEOLOGICAL HETEROGENEITY OF MOUTH BAR ON THE HYDRODYNAMICS OF THE RESERVOIR ROCK OF RED FOREST FIELD (CHINA)

摘要

The article considers the geological structure of C₆ productive bed of Red forest oilfield (China). It is determined that reservoir rock belongs to mouth bar of delta front. The survey shows the laminated structure of the reservoir, consisting of several regressive sedimentation cyclical beds separated by impermeable clay layers. In the structure of the regression mouth bar are dedicated two subfacies: crest and slope. It is established that crest subfacie is characterized by high grain maturity and made more powerful and homogeneous sandy sediments with high permeability properties. Slope subfacie of mouth bar has a high stratification with frequent interlayering of discontinuous thin sand bodies composed of immature sediments with the deterioration of reservoir properties.The presence of macroheterogeneity in bar sediments determines the filtration reservoir structure and its dynamics that must be considered when selecting the system of the injection wells location, the design of horizontal wells and design of hydraulic fracturing. It is shown that the most significant effect on the fluid dynamics of the reservoir have a layered structure of the reservoir, the location of injection and production wells in relation to the bar body and, especially, differences in the azimuthal direction of seepage flow and the strike of mouth bar sand bodies. The simulation results showed that the reservoir with a large number of layers is watered with more effectively, and the amount of remaining oil in it more than in the reservoir with a small number of layers; quick the water-cut and the decline in oil production are established in models where the sand body strike coincides with the direction of fluid flow. Recommendations on the organization of the flooding system for optimal oil extraction of laminated heterogeneous bar reservoir.