Optimization Of Influential Factors To Polymer Flooding In Gudao And Shengtuo Oilfield

It was proved that polymer flooding was an effective method to improve oil recovery by the laboratory and field experiments. At present, the blocks of polymer flooding have been developed from first-order oil reservoirs to second-order and third-order oil reservoirs. To make the two types of reservoirs also develop polymer flooding on a large scale, we must select polymer type suited to the two types of reservoirs, study and optimize the factors to polymer flooding.In view of the condition of Gudao and Shengtuo oilfield, we have selected the polymer type through the evaluation experiment of polymer performance. Based on the oil displacement experiments of the selected polymer in the homogeneous and heterogeneous models, the factors including oil-to-polymer viscosity ratio, oil viscosity, permeability, the amount of polymer, the timing of high concentration polymer solution injection were studied and optimized. The data of the experiments show that the reasonable oil-to-polymer viscosity ratio are 0.6 and 0.8 in the condition of Gudao and Shengtuo oilfield; the best oil viscosity of polymer flooding should be no higher than 100 mPa·s; the best formation permeability of polymer flooding is 2.0μm2 in the condition of Gudao and Shengtuo oilfield; the higher polymer slug volume is, the higher oil recovery is, and the increased oil recovery range become small gradually; with the same augmented oil recovery ratio, the higher the polymer solution concentration is, the smaller polymer slug volume is; the sooner high concentration polymer solution injection is, the better the oil recovery result is. The experiments above provides theoretical basis and technical support to further studying the enhanced oil recovery methods of second-order reservoirs, which is of great significance to oilfield application.