析蜡不可逆性对低渗高凝油流动性及水驱效果的影响  

Effect of wax precipitation irreversibility on flowability and water flooding for high pour point crude oil in low permeability reservoir

作　　者：王业飞[1] 吴寒超 丁名臣[1] 陈五花[1] 司永昌 李强[1,3] WANG Yefei;WU Hanchao;DING Mingchen;CHEN Wuhua;SI Yongchang;LI Qiang(School of Petroleum Engineering in China University of Petroleum(East China),Qingdao 266580,China;CPMC Tianjin Design Institute,Tianjin 300457,China;Shengli Oilfield Company of SINOPEC,Dongying 257001,China)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]中国石油北京项目管理公司天津设计院,天津300457 [3]中国石化胜利油田分公司,山东东营257001

出　　处：《中国石油大学学报(自然科学版)》2023年第6期80-86,共7页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家重点研发计划政府间国际科技创新合作重点专项(2021YFE0107000);国家自然科学基金面上项目(52074339);山东省自然科学基金面上项目(ZR201911080151)。

摘　　要：高凝油析蜡具有不可逆性,对注水开发及油藏后期进一步提高采收率造成影响。系统对比降温和升温模式下高凝油析蜡-溶蜡行为、黏度、流变性、油相渗流能力及水驱效果。结果表明:某高凝油溶蜡点为71.5℃,明显高于其析蜡点的62.3℃,存在不可逆性;温度高于溶蜡点时,降温和升温模式中原油黏度值基本相同,水驱采收率相当;温度介于溶蜡点和析蜡点时,降温模式中原油未析蜡,黏度小,为牛顿流体,无渗流启动压力,水驱采收率较高(超过60%);升温模式中蜡晶未完全溶解,黏度高,为非牛顿流体,存在启动压力,水驱采收率明显降低(小于50%),不可逆性影响显著;对于已受冷伤害的高凝油油藏,注热小幅度提高油藏温度是不够的,必须达到溶蜡点以上,否则水驱效果会明显变差。Wax precipitation of high pour point oil is irreversible,which has significant effect on development of water injec-tion and other enhanced methods.Under cooling and heating procedures,the wax precipitation-wax dissolution behavior,vis-cosity,rheological property,oil phase seepage ability and water flooding efficiency of high pour point oil were systematically compared.The results show that the wax dissolution temperature of a high pour point oil is 71.5℃,which is significantly higher than the wax precipitation point of 62.3℃,and there is irreversibility.When the temperature is higher than the wax dissolution point,the crude oil viscosity values in the cooling and heating modes are basically the same,and the water flood-ing recoveries are equivalent.When the temperature of the crude oil is between the wax dissolution point and the wax precipi-tation point,the wax does not precipitate during the cooling process,and the viscosity is relatively small,showing Newtonian fluid performance and having no seepage starting pressure,and higher water flooding recovery(more than 60%).In the heating mode,the wax crystal is not completely dissolved,the viscosity is high,and it is a non-Newtonian fluid.There is a starting pressure,and water flooding recovery is significantly reduced(less than 50%),indicating the obvious irreversible effect.Considering cold damage of high pour point oil reservoir,its temperature is not enough to be slightly increased by hot water injection,and it should reach above the wax melting point,otherwise the water flooding efficiency will be significantly worse.

关 键 词：高凝油 温度 析蜡不可逆性 流动性 水驱采收率 

分 类 号：TE349[石油与天然气工程—油气田开发工程]