磺基甜菜碱BS11/聚合物复合体系驱油实验研究

The Results of Core Flooding Experiment by Sulfobetaine/Polymer Combinational System

考察了以磺基甜菜碱为表面活性剂的SP二元和ASP三元复合体系在大庆油田条件下的岩心驱油效果。所用岩心为环氧树脂胶结石英砂均质和非均质(变异系数0.65)人造岩心。岩心水驱后分别注入0.35 PV BS11/聚合物(2.0/2.5 g/L)二元体系、Na3PO4(牺牲剂)/BS11/聚合物(4.0/2.0/2.5)三元体系、NaOH/重烷基苯磺酸钠Sy/聚合物(1.0/3.0/2.5)三元体系,再注入0.20 PV 1.0 g/L聚合物溶液,测得均质岩心复合驱采收率增值分别为25.8%,27.3%,25.7%(2个岩心的平均值),非均质岩心上分别为26.2%,27.7%,26.1%(单个岩心的测值),无碱的BS11二元体系的驱油效果与大庆油田使用的常规强碱ASP三元体系相当,加入少量Na3PO4可改善该二元体系的驱油效果。从均质岩心流出的BS11二元和三元体系,与模拟原油(黏度10 mPa.s)之间的界面张力(最低值)达到10-3mN/m。图2表2参6。

The core flooding results by SP and ASP solutions containing a sulfobetaine, BS11, as surfactant at conditions of Daqing oilfield are presented. The cores used are artificial quartz sand models consolidated by epoxy resin, homogeneous and heterogeneous, with permeability variation coefficient 0.65.0.35 PV of binary BS11/polymer （2.0/2.5 g/L）, tertiary sodium phosphate （as sacrificial agent）/BS11/polymer （4.0/2.0/2.5 g/L） or NaOH/heavy alkylbenzene sulfonate Sy/polymer （10.0/3.5/2.5 g/L） solutions are injected into cores having been waterflooded to 98% water cut and followed by 0.20 PV of 1.0 g/L polymer solution as postpad and successive water flood to 98% water cut again; the enhancement in oil recovery by combinational chemical flood measured is of 25.8 %, 27.3 % or 25.7 % on homogeneous cores as averaged over 2 cores and of 26.2%, 27.7% or 26.1% on heterogeneous cores as single core measurement, respectively, that is, the oil displacement efficiency （ODE） of the alkaline free binary BS11/polymer system is similar to that of the NaOH containing tertiary ASP system used in Daqing and a small amount of Na3PO4 introduced can improve the ODE of the binary BS11/polymer system. The binary and tertiary BS11 systems flown out of the cores create ultralow interfacial tension of magnititude 10^-3 mN/m （the minimum of dynamical interfacial tension）.