油砂的ζ电位对MD-1膜驱剂吸附的影响及吸附动力学和热力学研究  

Adsorption of MDFF Agnet MD-1 from Aqueous Solution on Reservoir Sand in Relation to Surface Zeta Potential with Dynamical and Thermodynamical Treatments

作　　者：高芒来[1] 刘勇[1] 孟秀霞[1] 王建设[1] 

机构地区：[1]石油大学(北京)化工学院,北京102249

出　　处：《油田化学》2003年第2期167-171,共5页Oilfield Chemistry

基　　金：中国石油天然气股份公司导向试验基金资助(项目编号B9802)。

摘　　要：采用静态吸附法研究了不同pH值下MD 1膜驱剂在大庆主力油藏洗油油砂上的吸附特性。实验结果表明油砂悬浮液的pH值明显影响油砂粒子表面的带电性,大庆主力油藏油砂的pHzpc=2.58,pH<2.58时油砂的表面带正电,pH>2.58时,油砂的表面带负电,且pH值越高,表面负电荷越多。油砂对MD 1膜驱剂的饱和吸附量As随ζ电位的降低很快增加,电位是决定吸附的主要因素。当ζ电位降到一定值(约为-60mV)以下时,饱和吸附量As几乎不再随ζ电位的降低而变化。吸附动力学研究表明,油砂颗粒表面电位越低,对MD 1膜驱剂的吸附活化能越小,要克服的吸附势能垒越低,吸附MD 1膜驱剂的速度越快,吸附MD 1膜驱剂的静电作用越强。温度对吸附速率影响不大。吸附热力学研究表明,吸附过程是自发且放热的,而且放热很大,pH=10.03时ΔH=-79.33kJ/mol,pH=4.04时ΔH=-38.84kJ/mol。pH值越高,放出的热越多,吸附后体系越稳定。pH越高,油砂表面电荷量越大,越有利于MD 1膜驱剂的吸附。图5表2参14。The adsorption behavior of molecular deposition filming/flooding (MDFF) agent MD1 from aqueous solution onto deoiled reservoir sand from main district of Daqing is studied by static method. It is shown that the pH value of the solution exerts significant effects on surface electricity of the reservoir sand, for which pHzpc=2.58, the surfaces of the sand grains are charged positively at pH<2.58 and negatively at pH>2.58 and the higher the pH value, the more the negative charges exists on the surfaces. It is also shown that the saturation adsorption amount of MD1, As, on the sand increases rapidly with decrease of zeta potential as a main determinative factor in MD1 adsorption and becomes practically constant when zeta potential being lower than a certain value, -60 mV ca. The dynamical results show that the lower the zeta potential on the surfaces, the less the activation energy of adsorption is, the lower the adsorption potential barrier is, the faster the adsorption proceeds and the stronger the electrostatic interactions between the surfaces and the MD1 molecules are meanwhile temperature influences the adsorption rate unnoticeably. The thermodynamical results show that the adsorption proceeds spontaneously and highly exothermally, the adsorption enthalpy is of -79.33 kJ/mol at pH=10.03 and -38.84 kJ/mol at pH=4.04. The higher the pH value, the more exothermal and the more stable the system is. At higher pH value more electric charges appear on the surfaces of the reservoir sand grains and the adsorption of MD1 is more favored.

关 键 词：油砂 Ζ电位 MD-1膜驱剂 静态吸附法 吸附动力学 热力学 大庆油田 

分 类 号：TE357.46[石油与天然气工程—油气田开发工程] TE39