川南地区龙马溪组页岩润湿性分析及影响讨论  

Analysis of the Wettability of Longmaxi Formation Shale in the South Region of Sichuan Basin and Its Influence

作　　者：刘向君[1] 熊健[1] 梁利喜[1] 罗超[1] 张安东[1] 

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500

出　　处：《天然气地球科学》2014年第10期1644-1652,共9页Natural Gas Geoscience

基　　金：国家自然科学基金项目"硬脆性泥页岩地层井周裂缝形态调控岩石力学基础研究"(编号:51274172);国家自然科学基金重点支持项目"页岩气低成本高效钻完井技术基础研究"(编号:U1262209)联合资助

摘　　要：国内外大部分学者研究认为泥页岩表面润湿性为水湿,而页岩气藏中页岩岩石存在有机质影响,页岩表面润湿性表现比较复杂,因此选择四川盆地龙马溪组野外露头及井下岩心进行分析,通过开展一系列实验,研究分析了龙马溪组页岩润湿性,并从3个方面初步探索讨论了润湿性对页岩气藏的影响。研究结果表明龙马溪组页岩表面既亲油又亲水,且页岩表面更倾向于油湿,页岩岩石孔隙表面处润湿性存在差异,出现非均匀润湿性即斑状润湿;页岩自吸吸水率、吸油率随时间增加而先上升后趋于稳定,页岩自吸吸水率大于自吸吸油率;页岩浸泡在水中水化应力随着时间增加而先呈上升后趋于稳定,而先浸泡白油后浸泡水中水化应力上升速度减慢;页岩硬度随浸泡时间增加、浸泡温度升高以及浸泡压力增大而呈下降趋势,其中浸泡白油中硬度下降幅度较小,而浸泡水中硬度下降幅度较大;页岩表面吸附特性与表面自由能有关,表面自由能随水接触角减小而增大,同时页岩表面亲油对气态烃有较强吸附能力;页岩表面亲水性易造成水锁,而表面亲油性可减轻水锁伤害,页岩气藏水锁伤害评价应考虑页岩表面既亲油又亲水特性影响;油基钻井液对页岩强度影响较小,而水基钻井液对页岩强度影响较大,易造成井壁失稳,水基钻井液体系优化需考虑抑制其水化作用。Researchers suggest that shale wettability was water-wet,but the presence of organics would affect shales and complicate the interpretation of wettability in shale gas reservoirs.Therefore,experiments were done with outcrop and core samples from the Longmaxi Formation shale of the southern region of Sichuan Basin to determine shale wettability,and the wettability effects on the shale reservoirs were preliminary discussed from three respects.The result shows that the wettability of the Longmaxi Formation shale is water-wet and oil-wet,and the wettability is more tend to oil-wet.The wettability of the pore surface of rocks is different,displaying inhomogeneous wettability and mixed wettability.The oil absorption rate of spontaneous imbibition and water absorption rate of spontaneous imbibition of the shale tend to increase first and then become stable with the increase of time,and the oil absorption rate of imbibition is bigger than the water absorption rate of imbibition.The hydration swelling stress of the shale tends to increase first and then become stable with the increase of time.For the shale rocks which have been soaked in oil first and then experienced hydration swelling stress test,the increase of velocity of hydration swelling stress would slow down.The hardness of the shale will decline with the increase of soaking time,temperature and pressure.And in the white oil,the trend is smaller.While in the water,this trend is more obvious.The adsorption characteristics of the shale surface are related to the surface free energy,which increases with the decrease of surface water contact angle.Meanwhile,the oil-wet of the shale surface has strong adsorption capacity for gaseous hydrocarbon.The water-wet surface can cause water blocking damage,but the oil-wet surface can lessen water blocking damage.So in shale reservoir,it is necessary to consider the influence of oil-wet and water-wet behavior in shale surface.The oil based drilling fluid has little influence on the strength of shale rock,while the water based d

关 键 词：龙马溪组页岩 润湿性 油湿 水湿 吸附特性 水锁 井壁稳定 

分 类 号：TE121.3[石油与天然气工程—油气勘探]