| Popis: |
In this paper, the authors demonstrated, using the Nelson criterion, that in case when 50% of cumulative oil production is provided by 5–15% of the wells many fields with terrigenous type of reservoir are characterized by a significant influence of fracturing on reserves recovery. In addition to seismic attributes, the technological performance of wells and logging data were analyzed (the ratio of the actual and estimated flow rates, the frequency of oil rate surge, the ratio of buffer pressure and injectivity, local deviation of OWC, the proportion of active thickness, the quality of cement sheath) which allows to specify the location of the decompression zone. Relation of these characteristics to abnormal well operation was confirmed by the method of statistical hypothesis testing. A high correlation between seismic attributes, which characterize disjunctive faults, and the well performance was observed (oil and liquid rate, water cut), as well as geological structure features (net pay thicknesses, net sand and macro-heterogeneity). Based on the development analysis of one of the fields in Kazakhstan the authors demonstrated a strong dependence between production performance of the area and well placement system, as well as the injectivity of displacing agent in a faulted reservoir. The dependence between the displacement efficiency and injection rate was theoretically confirmed by using the displacement characteristics obtained within this study on the basis of the equation for water saturation in fractured porous media [17]. The fundamental possibility and technological efficiency of waterflood systems transformation based on localization of decompression zones was demonstrated. |
