Water injection as a method of pressure maintenance on a high-oil-viscosity fields causes unstable displacement front. In its turn it may lead to appearance of non-covered by water flood segments, and low development efficiency may be as a result. In this case use of polymer solutions as pressure maintenance agent may lead to better development efficiency. This article considers the results of numerical and theoretical calculations for polymer flooding on a high-oil-viscosity field. Two case of polymer flooding was investigated: non-stop polymer flooding and cyclic polymer flooding. Cyclic polymer flooding means that slugs of polymer solution and slugs of water injects in the same well alternately (with different time-periods). Polymer concentration within each calculation has not been changed. Obtained results shows a method of polymer flooding have a good performance. Both of technological and economical effects are higher than in case of waterflooding. However, underlaying water may lead to extremely low effects because of polymer solution losses (it may flow through underlaying water but not through oil-soaked formation). Cyclic polymer flooding in comparison with non-stop polymer flooding shows better performance. Thus NPV increasing equal to 20% in case of cyclic polymer flooding an 16% in case of non-stop polymer flooding. Also an important dependency has been investigated: polymer/water period length ratio (for cyclic polymer flooding) depends on polymer concentration. This dependency can be described by power equation. Coefficients of this equation may depend on different characteristics of geological feature, fluid properties and relative permeability curves. Evaluation of this dependencies and creation of i-charts (based on results of this evaluation) may simplify procedure of optimal parameter definition for polymer flooding.
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