نوع مقاله : مقاله پژوهشی
نویسندگان
دانشگاه صنعتی شریف
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The mechanisms involved in increased oil recovery by low-salinity waterflooding are divided into two general groups: fluid-fluid and rock-fluid. Among these mechanisms, fluid-fluid interactions have been investigated less in the published literature. One of the effects of these interactions is maintaining or increasing the connectivity of the oil phase, which increases the relative permeability of the oil phase and its production rate from the reservoir. In this research, for a deeper understanding of these effects and the time scale of their effects, the coalescence of two adjacent oil droplets in the vicinity of a saline water has been investigated. A new device and method was developed to study this phenomenon. According to this method, two drops of oil (one pendent from the top and one from the bottom) are placed in the vicinity of the desired brine, and after an aging time, they are brought close to each other to start contacting with each other. After the contact, it takes some time for the droplets to coalesce, which is recorded as the "coalescence time". Based on the obtained results, the coalescence time increases with the increase of the aging time and remains almost constant after 15 minutes. Also, the coalescence time of two oil droplets shows a nonmonotonic behavior with salinity and reaches its maximum value at an intermediate salinity. The maximum coalescence time occurs at a lower ionic strength in brines containing divalent salts such as calcium, magnesium and sulfate compared to that in monovalent salts. These values for sodium chloride, magnesium chloride, calcium chloride and sodium sulfate brines are 0.5, 0.05, 0.05, 0.01 M respectively. The results of this study highlights that there will be an optimal salinity for fluid-fluid effects in low-salinity waterflooding. Understanding their effect on oil recovery requires waterflooding experiments.
کلیدواژهها [English]
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