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Low salinity waterflooding is presently one of the most promising enhanced oil recovery (EOR) methods. Wettability alteration and residual oil decrease are the most important EOR mechanisms of low salinity waterflooding. However, the mobility control EOR due to fines migration, induced by low salinity water, and the consequent flux diversion is also an important feature of the smart waterflooding. We analyze the limited available field data from 10 years of low salinity water injection in Bastrykskoye field. The mathematical model for fines-assisted waterflooding is used for history matching resulting in good agreement between the field and modeling data. The model is used to compare recovery factor for two scenarios of low salinity water injection and formation (normal) water injection. Low incremental recovery and low decrease in the amount of produced water during the development of Bastrykskoye field is explained by the production of significant amount of the reservoir water before the commencement of...

Low salinity waterflooding is a very promising EOR method in recent years. The mechanisms of enhanced recovery are considered to be decrease of residual oil saturation and alternation of rock wettability. In addition, the mobility control mechanism due to induced fines migration by low salinity water, and the consequent flux diversion is also a possible mechanism for enhanced recovery in low salinity waterflooding. The current paper analyzes production and injection history data from 24 years of production from Zichebashskoe field (Russia) which includes 7 years of low salinity water injection. The mathematical model for waterflooding with fines migration is applied for history matching. The result is a good agreement between the field history and modelling data. The Roxar tracer model is then used to compare recovery factor for two scenarios of low salinity water injection (field history) and conventional water injection using formation water (High salinity). The results shows insignificant incremental recovery ( 45% of total produced water) before the commencement of low salinity water injection and also injectors placing. A two layer cake reservoir is built using Zichebashskoe field permeability distribution to study the effect of low salinity water injection in a 5 spot pattern. Modeling results show significant improvement in oil recovery (~10%) and large reduction of water cut.

Low salinity waterflooding is presently one of the most promising EOR methods. Wettability alteration and residual oil decrease are the most important EOR mechanisms of low salinity waterflooding. However, the mobility control EOR due to fines migration, induced by low salinity water, and the consequent flux diversion is also an important feature of the smart waterflooding. We analyze the limited available field data from 10 years of low salinity water injection in Bastrykskoye field (Russia) and 24 years of production from Zichebashskoe field (Russia) which includes 7 years of low salinity water injection. The mathematical model for fines-assisted waterflooding is used for history matching resulting in good agreement between the field and modelling data. The model is used to compare recovery factor for two scenarios of low salinity water injection and formation (normal) water injection. Low incremental recovery and low decrease in the amount of produced water during the development of both fields is explained by the production of significant amount of the reservoir water before the commencement of low salinity water injection and also the injectors placing.

During the last two decades, low salinity waterflooding as a part of more general varying water composition has become a promising EOR method. Nevertheless, the physics mechanisms of extra oil recovery by low salinity waterflood are not clearly understood. Yet, fines migration and consequent permeability reduction may occur as a result of reduction of water salinity that can divert the water flux. This effect must be accounted in low salinity waterflood modelling. Moreover, the flux diversion due to induced-fines migration could be utilized to improve the reservoir sweep. In the current study the Tempest software is applied to build a model and history match 25 years of low salinity water injection in Bastrykskoye field (Russia). The model is then used to compare recovery factor for two scenarios of low salinity water (LSW) injection and formation water (FW) injection. The modeling results show an insignificant change in recovery factor between two scenarios of LSW and FW injection. This low incremental recovery is explained by the production of a significant amount of the reservoir water (FW) before the commencement of low salinity water injection. A sensitivity study shows that the location of the injectors can highly affect the incremental recovery obtained by LSW injection. A 2-layer model with 5-spot pattern shows a significant incremental recovery (8%) during injection of LSW as compared to the injection of formation water (FW).