Study On Heterogeneity Of Braided-Delta Sedimentary Glutinite Reservoir

Reservoir heterogeneity is the most important factors to influence on payzone production prediction and evaluation for waterflooding fracturing reservoir.KB Oilfield is currently in the development stage. Previous studies showed that KB oilfield Q12E31reservoir have the characteristics of insufficient natural energy, pressure drop fast, fast production decline, well productivity differences, which constraints on the efficient development and ongoing production.Based on the construction of the reservoir layer structure and the reconsideration of the sedimentary microfacies, the paper concentrates on the heterogeneity evaluation, different theories and techniques of many subjects including sedimentary, reservoir geology, petroleum production geology and so on had been uesd, focus on the reservoir microscopic heterogeneity, in-layer heterogeneity, interlayer heterogeneity, and plane heterogeneity.then heterogeinity integrated analysis is carried out. Finally, the3D geological model for KB oilfield was built by applying reservoir stochastic modeling technology with RMS software.Studies suggest that a layer by layer onlap faulted anticline structure was developed along the north west dip direction on the ancient bumps background, in the process of long-term base level continued rising, a multi stage short-middle term cycles transgression regression glutenite was developed, making gravel reservoir have characteristics of braided river delta sedimentary. Because of strata onlap, the bottom of the E1+2formation missing in the area, and therefore only the braided river delta plain developed (including water diversion channel, heart beaches, flood plains microfacies).Core observation shows that alluvial layers bedding and massive bedding is more developed. Affected by the hydrodynamic conditions, the overall are mostly composite rhythms. From the bottom to up target layer has the characteristic with an increase in the number of interlayer, the main type are property, fewer lithology. After a comprehensive heterogeneity evaluation layer L1has medium heterogeneity, layer L2has strong, layer L3have weakly heterogeneity.Three-dimensional properties geological modeling of reservoir and three-dimensional flow line waterflood simulation results suggest that along the source direction (North West-South East) perpendicular to the axis of the anticline, reservoir heterogeneity is relatively weak, sandbody communication in the plane and profile is well, thus it is waterflood efficiency advantages direction, sandbody in river channel became the dominant channel seepage paths and waterflood front advancing speed is significantly larger along the river channel direction, reservoir heterogeneity is strong perpendicular source direction. Interbed development lead to poor connectivity in cross-section and in the plane, therefore, waterflood front advance was blocked, water flooding were not effective.The studies of the paper will give significant guide to efficient develop the braided river delta conglomerate reservoir with fracturing water development and rapid build productivity.