利用盐水调节油藏岩石表面润湿性  

Surface wettability control of reservoir rocks by brine

作　　者：林梅钦[1,2] 华朝[3,4] 李明远 

机构地区：[1]中国石油大学(北京)提高采收率研究院,北京102249 [2]中国石油天然气集团公司三次采油重点实验室,北京102249 [3]海洋石油高效开发国家重点实验室,北京100028 [4]中海油研究总院,北京100028

出　　处：《石油勘探与开发》2018年第1期136-144,共9页Petroleum Exploration and Development

基　　金：国家科技重大专项(2017ZX05009-004);国家自然科学基金(51274211)

摘　　要：基于岩石表面基团与有机物分子间的黏附模型,分析油藏岩石表面的化学基团与原油中不同组分之间的微观作用力以及岩石表面和原油-盐水界面处双电层之间的相互作用,研究盐水中H^+、OH^-和无机盐离子对岩石表面润湿性的调节能力及其微观机制,并建立了油藏润湿性调节的新方法。原油中有机物质与岩石表面基团之间存在范德华力、氢键、库仑力和表面力相互作用,改变这些相互作用力,利用盐水调节岩石表面润湿性的机理包括:化学基团转化、界面电势改变、注入水pH值改变、多组分离子交换及盐溶/盐析效应。对砂岩油藏,随着盐水中阳离子价态、盐水浓度降低或盐水pH值(对矿化度影响不大)增加,原油与岩石表面间相互作用变弱,岩石表面亲水性增强;对碳酸盐岩油藏,高矿化度CaSO_4、MgSO_4盐水有利于增强油藏岩石表面亲水性。因此通过调节注入水的离子组成可调控油藏岩石表面亲水性,提高原油采收率。Based on adhesion models between rock surface groups and organic molecules, the interactions between the chemical groups on the rock surface and the components of crude oil and the interactions of the electrical double layers at the rock surface and oil-water interface were analyzed to investigate the abiltyes and microscopic mechanisms of wettability control by H^＋, OH^- and inorganic salt ions in brine, and a new method of wettability control for reservoir rocks was built. The results show that the interaction forces between rock surface groups and oil molecules are van der Waals forces, Coulomb forces, hydrogen bonds, and surface forces. By changing these forces, the control mechanisms of surface wettability of reservoir rocks by brine are： transformation of chemical groups, change of interfacial potential, pH variation of injected water, multicomponent ionic exchange, and salting-in or salting-out effect. For sandstone reservoirs, with the decrease of concentration and valence state of positive ions in brine or the increase of pH （increasing pH has a negligible impact on the brine salinity）, the interaction between rock surface and oil becomes weak, thus resulting in increase of water wettability of rock surface. For carbonate resvervoirs, CaSO4 or MgSO4 brine with high concentration is beneficial to increase water wettability of rock surface. Therefore, it is feasible to control rock wettability and improve oil recovery by adjusting the ion components of injected water.

关 键 词：岩石表面润湿性 盐水 分子间作用力 微观机理 提高采收率 

分 类 号：O647[理学—物理化学] TE3[理学—化学]