摘要
MD膜驱油已成为提高采收率的一种新方法。为了深入认识其驱油机理,实验测定了从兴隆台油田驱油现场取得的两个MD膜驱剂样品MD A100和MD A200的表面张力和界面张力、表面润湿性、表面电性并进行了讨论。MD A100为单分子双季铵盐MD 1的250g/L水溶液,MD A200为MD 1同系物的180g/L水溶液。结果表明:MD膜驱剂没有表面活性和界面活性,不是表面活性剂;MD膜驱剂能改变表面润湿性,可将强水湿表面(相对接触角为4.2°)转变为中性润湿(1800mg/LMD A100和MD A200溶液的相对接触角为89.9°和88.4°),可将油湿表面(114.1°)转变为中性润温(分别为90.2°和91.5°)。MD膜驱剂溶液能改变表面电性,当MD膜驱剂的质量浓度由600mg/L增加到900mg/L(亲油砂)或由900mg/L增加到1200mg/L(亲水砂)时负电表面转变为正电表面,即存在一个zeta电位为零的浓度。这说明MD膜驱剂驱油时润湿反转机理和表面电性反转机理起主要作用,也即MD膜驱剂的强烈吸附作用改变了砂岩表面的性质,引起原油存在状态的变化,从而有利于原油的采出。表3参7。
MD filming/flooding (MDFF) has become a new method of EOR. In order to deepen the knowledge of the oil displacement mechanisms involved, the surface and interfacial tensions, wetting capacity, and surface electrical behavior are determined and discussed for two samples of MDFF agent taken from MDFF pilot area at Xinglongtai, Liaohe: MDA100 as a 25% solution of organic diammonium salt MD1 and MDA200 as an 18% solution of homologue of MD1. It is shown that the two samples of MDFF agent have no surface and interfacial activity and are not surfactants; they can change surface wettability, converting a strongly waterwet surface of relative contact angle (RCA) in kerosene 4.2° to a neutrally wet one of RCA=89.9° and 88.4° and an oilwet surface of RCA=114.1° to a neutrally wet one of RCA=90.2° and 91.5℃ for 1 800 mg/L MDA100 and MDA200 solutions, respectively; they can change surface electrical behavior and the conversion of negatively charged surfaces to positively charged ones is observed with MDA100 or MDA200 concentration in solution raising from 600 to 900 mg/L for a lipophilic sand and from 900 to 1 200 mg/L for a hydrophilic one, that is, there exists a solution concentration at which the zeta potential becomes zero. It is concluded that the conversion of wettablity and surfac electricity plays important roles in MDFF, or, in other words, the strong adsorption of MDFF agent changes the properties of rock surfaces and in turn the situation of reservoir oil in favor of oil recovery.
出处
《油田化学》
CAS
CSCD
北大核心
2003年第2期172-174,共3页
Oilfield Chemistry
关键词
MD膜驱剂
驱油机理
表面张力
表面润湿性
表面电性
MD filming/flooding agent
surface/interficial tension
surface wettability
surface electricity
oil displacement mechanisms
