| Autor: |
R. D Kanevskaya, K. D Budkin, S. V Korobkin, O. V Lubimova, A. A. Pimenov, T. G. Isakova, A. Yu. Markova |
| Rok vydání: |
2017 |
| Zdroj: |
Day 2 Tue, October 17, 2017. |
| Popis: |
Rock wettability and its transformation in the process of formation and development of oil deposits is a crucial factor influencing fluid content and many aspects of reservoir performance, particulary in waterflooding and enhanced oil recovery techniques. The saturation concept for the complex carbonate reservoir with the variable wettability is presented. It is shown that rock wettability can significantly affect large-scale fluid distribution processes in the oil-saturated reservoir. The analysis of the geophysical characteristics of the cross section allowed to separate three geological units with significantly different values of the electrical resistivity. By means of joint analysis of core examination and geophysical well logging it is demonstrated that zones of the «low-resistivity» geological unit are chiefly characterized by hydrophobik type of rock wettability, while zones of the «high-resistivity» unit are typically described by hydrophilic type of rock wettability. The predominantly hydrophobic unit lies between two hydrophilic and less permeable units. Oil saturation model is designed with the assistance of field and core data based on the capillary-gravitaty equilibrium concept taking into account variable rock wettability. The results of the relative permeability experiments and data on the initial water cut of well production are also used to identify initial saturation distribution in reservoir. In the predominantly hydrophobic unit, the transition zone is insignificant and partially below the free-water level. There is water alone in the hydrophilic units at these depths. At depths corresponding to the transition zones of the hydrophilic units, there is an area of high oil saturation in the predominantly hydrophobic unit. The presented approach to the creating of the saturation model enabled to consider previously ignored factors (the electrical resistivity of the geological units, the presence of bridges between them) that affect the efficiency of the reservoir pressure maintenance system and recovery of reserves. The identification of the thick lower unit with high water saturation made it possible to determine the source of water encroachment and explain the nature of water encroachment of production wells. The proposed concept of the complex carbonate reservoir saturation with the variable wettability allowed to connect well log, core and field data to a single consistent model. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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