摘要
裂缝发育的低渗灰岩储层,当基质岩块为混湿及油湿时,毛细渗吸驱油作用很弱。本工作采用毛管上升、渗吸及相对渗透率曲线方法,在62℃下研究了CTAB和SDBS溶液对油湿灰岩表面性质及渗吸行为的影响。浓度为700mg/L时,SDBS溶液与原油间的界面张力为0.035mN/m,而CTAB溶液为1.25mN/m;随着浓度增大,SDBS溶液使亲油的毛管表面润湿接触角缓慢减小,而CTAB溶液使润湿接触角大幅减小,在与最大吸附量对应的浓度下润湿接触角有最低值;亲油岩心在CTAB溶液中的渗吸驱油速度较SDBS溶液中的渗吸驱油速度高;相渗曲线表明,与亲油岩心/SDBS溶液体系相比,亲油岩心/CTAB溶液体系的油相相对渗透率较高而水相相对渗透率较低。因此,CTAB类阳离子表面活性剂可望用于该类油藏的开发。讨论了相关的机理。图6参10。
For naturally fractured low permeable limestone reservoirs, the oil displacing function by spontaneous imbibition of water is weak when the matrix rock surfaces are mixed wet or oil wetted. In this work the influence of surfactants CTAB and SDBS on the surface properties and imbibition for oil wet limestone is investigated at 62℃ by the ways of capillary rise, imbibition, and relative permeabilities curves. The interfacial tension for SDBS aqueous solution is determined to be 0.035 mN/m and that for CTAB aqueous solution—1.25 mN/m when solution concentration being of 700 mg/L. In solution of increasing concentration SDBS reduces the wetting contact angle on lipophilic capillary surfaces moderately and CTAB—significantely with a minimum contact angle observed at the concentration corresponding to the maximum adsorption on oily sand. The oil displacement by imbibition of aqueous CTAB solution into the oil wet limestone core proceeds faster than that of aqueous SDBS solution. The relative permeabilities curves obtained show that the relative permeability for oil phase is higher and for aqueous phase is lower in the system oil wet core/CTAB solution than that in the system oil wet core/SDBS solution. It is considered that the cationic surfactants such as CTAb might be used in development of the reservoirs mentioned. The mechanicsms involved are discussed.
出处
《油田化学》
CAS
CSCD
北大核心
2004年第1期52-55,67,共5页
Oilfield Chemistry
关键词
表面活性剂
渗吸行为
低渗灰岩油藏
油湿基质岩块
润湿性
驱油技术
imbibition
low permeable limestone reservoirs
oil wet matrix rock
wettability alteration
surfactants
oil displacement
