Experiment Research Of Eor By Steam Flooding After Polymer Flooding In Non-homogeneous Reservoir

The application of chemical flooding after water flooding technology has made a great contribution to maintaining oil field high production, stable production and sustainable development at our old oil fields. But there still is about 50% petroleum reserves reversed in the reservoirs after chemical flooding, such as polymer flooding and triaxial compound flooding. And it would ensure the sustainable development that if steam flooding could increase recoverable reserves precipitously, prolong obviously production life on the base of polymer flooding. In this paper, we us the natural cylindrical cores of Daqing oil field to study the routine and profile control steam flooding of non-homogeneous oil reservoir constituted with three parallel cores, the mean permeability is 730×10^-3μm² and variation coefficient is 0.72. This experiment was conducted in the two temperature field conditions of reservoir and injection medium. The results showed that the routine steam flooding after polymer flooding could increase oil recovery factor precipitously in the in non-homogeneous thin oil reservoir. And the scope could come to 26.19%, the oil-steam ratio is 0.127 when the injection temperature is 180℃.But the recovery scope came chiefly from secondary and high permeability zones, homologously were 25.30% and 31.39%, the low permeability layer was only 20.10%, the fractional flow ratio of low permeability layer, secondary and high permeability zones was1:1.75:2.44, there is one severe steam injection disequilibrium between them; at the same time, the recovery ratio raisesed as the increase of steam injection temperature and velocity, and the temperature of increasing scope obviously was 140℃, the scope is 20.61%, which was limited when raising temperature on this base. And the steam flooding recovery of 180℃was only 5.58% higher than that of 140℃; using PAM frozen glue, separated layer injection and profile control, could improve the anisotropic layer and raised utilization extent of low permeability layer, the recovery ratio of profile control steam flooding was 4.79%⁶.42% higher than that of routine steam flooding when 180℃is over. This made the whole recovery ratio of profile control steam flooding was 2.39%³.21% higher than that of routine steam flooding, come to 28.39%²9.47%, and the oil-steam ratio is 0.139; the profile control steam flooding effect of compounding SD-3 active agent and PAM frozen glue is the better, the steam flooding recovery is 30.58% on average, 5.37%⁶.29% higher than that of routine steam flooding, the oil-steam ratio come to 0.155. Secondly, the ideal effect are successively profile control steam flooding separated layer, steam flooding of slug with foaming agent and profile-control agent, steam flooding of slug with profile-control agent and foaming agent, their recovery ratios are separately 2.39%³.21%,1.53%².56%,0.53%¹.23% higher than that of routine steam flooding, the oil-steam ratios are separately 0.143,0.138,0.129.