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Profile Control and Flooding Effect of Alternate Injection of Cr3+
Polymer Gel and Water and Its Mechanism Analysis:
Taking the Bohai Oilfield as an Example
Zhang Baoyan, Lu Xiangguo, Xie Kun, Liu Yigang, Zhang Yunbao
Aiming at technical demand on relieving the reverse of imbibition profile, displacement effect of alternate injection of Cr3+
polymer gel and water was studied, taking reservoir of Bohai oilfield as simulation object, regarding injection pressure, water content and recovery efficiency as evaluation index. Results showed that as the displacement agent flowed into the medium and low permeability layer, on the one hand, the swept volume was magnified. On the other hand, seepage resistance and start
up pressure of imbibition were increased, thus resulting in the reverse of the imbibition profile. Once the alternate injection of Cr3+
polymer gel and water was adopted, polymer solution could get priority to flow into the high permeable layer and block off it, then subsequent water flowed into medium and low permeability layers to displace the oil. Therefore the phenomenon of the reverse of imbibition profile was relieved or even eliminated. Once the alternate injection of C3+
polymer gel and water was conducted in A22 injection well in LD5
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2 Oilfield, injection pressure get increased, which was good for enlarging sweep volume effect.
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