稠油热碱水系统界面张力和乳液特性研究

STUDIES ON INTERFACIAL TENSIONS BETWEEN HEAVY CRUDE OIL AND HOT ALKALINE SOLUTIONS AND BEHAVIOR OF EMULSIONS FORMED FROM THEM

主要研究了碳酸钠、氢氧化钠、硅酸钠三种碱与稠油的界面张力和碱液-稠油乳状液的特性,讨论了乳状液的驱油机理。结果表明,这三种碱液与稠油的界面张力在一定条件下均能达到10~2mN/m数量级以下;高油水体积比下的碱水-稠油乳液类型由碱浓度决定。

Hot alkaline flood is a suitable way of EOR for the reservoir District zero of Jinlow Oil Field, Henan, owing to ready emulsification of the heavy crude by alkaline. In this paper four alkalines are investigated in relation to alkaline/crude interfacial teasions(IFTs)and behavior of emulsions formed.Low IFTs of amplitude 10^(-2)mN/m are observed between solutions of Na_2CO_3, NaOH and Na_2SiO_3 and Jinlow crude at～60℃ and alkaline concentrations(C) 0.5-1.0%, The viscositytemperature curves go through a minimum for the emulsions with alkaline/crude ratio by volume≥6:4 and go up-≤5:5. Alkaline/crude(7:3)fresh water emulsions are of O/W type when C is high and W/O type when C is low, with transition C(Ct) for NaOH, Na_2CO_3, and Na_2SiO_3 being 0.3-0.5%, 1.0-1.5%,and 2.0-3.0%, respectively. With formation brine taken for emulsion preparation NaOH leads no change in Ct, Na_2CO_3 in all concentrations tested gives W/O emulsions with viscosity higher than that of the crude,and Ct is lowered to 1.2-2.0% for Na_2SiO_ NaHCO_ is unsuitable for the hot alkaline flood.