Profile Controlling Technology Research Using Residual Polymer After Polymer Flooding

Polymer flooding in Nan Er zone of Sa Nan development area has entered later stage of injecting polymer, partial injection wells of the zone has entered follow-up water flooding stage. Affected by layer heterogeneity, after follow-up water flooding, interlayer and layer contradiction is serious, injecting water sudden along high permeability layer in the plane, inefficient and invalid water cycle is serious. Flooding thickness ratio in vertical layer is greater, wells with ultra-high water cut increase. Therefore, controlling water cut increasing speed, reducing inefficient and invalid water cycle, and excavating residual oil potentiality of thick oil layer are the main direction of EOR after polymer flooding.In this paper, aiming oil layer geological features of Pu I 1-4 of Sa Nan zone, the author developed related physical model and numerical model, studied distribution property and water channeling law of residual polymer after polymer flooding. By evaluating the related property of positive ion amoeba particle profile control agent and, metal cross-linking agent and polymer gel system, the author provided theoretical basis for residual polymer profile control test after polymer flooding in site. The indoor experiment results show that plugging effect of metal cross-linking agent is better; utilization and blocking effect of residual polymer compound with amoeba is improved, which is better polymer re-use formula; polymer gel system has better blocking and resistance to erosion, whose blocking rate to high permeability core is greater, and can form low permeability barrier in high permeability position, has better profile control capability, and there is some increasing oil and reducing water effect in pilot test.