Research On Chemical Flooding Experiment In Sub-layers Reservior Of Daqing Oil Field

Chemical flooding of Daqing oilfield main layer has entered the later exploitation stage, in oreder to encure stable production, the chemical flooding of sub-layers is urgent. Because of the special geological features in sub-layers reservoir, the general method of injecting chemical agent does not fit the development of sub-layers. It makes the injection method of various molecular weights, in other words, in the same column the molecular weight regulator was builded, what can degrade the polymer solution through mechanical action which was injected to low-permeability layer and banlance the difference of the injection volume caused by permeability contrast.In this paper, it carrys out performance testing of polymer solution which flows through the molecular weight regulator, the results show that: the viscous and elastic of polymer solution decline after it flowing throug the molecular weight regulator, the extent increases with the increasing of molecular weight. Through doing flooding experiment of polymer solution which flows through the molecular weight regulator on the core with different permeability, the results show that: the recovery rate on the core with same permeability of polymer flooding which doesn't flow through the molecular weight regulator is higher than which sheared with the same molecular weight and the maximum injection pressure of polymer flooding is higher than which sheared with the same molecular weight. The recovery rate of polymer flooding sheared with higher molecular weight is higher than which unsheared but with the lower molecular weight.In this paper, it carrys out performance testing of the ASP combination system which flows through the molecular weight regulator, the results show that: the viscous of the ASP combination system declines after it flowing throug the molecular weight regulator, but the interfacial tension has a little alternation. Through doing flooding experiment of the ASP combination system which flows through the molecular weight regulator on the core with different permeability, the results show that: the displacement characteristics on the same permeability of the ASP combination system which doesn't flow through the molecular weight regulator is better than which sheared with the same molecular weight and the maximum injection pressure is higher. When multi-zone produce, recovery rate of different medium injection is higher than commingled injection, it can improve the producing reserves of the mid-permeability and low-permeability layers and decline the maximum injection pressure.