致密油纳米流体增渗驱油体系特征及提高采收率机理  

Characteristics and EOR mechanisms of nanofluids permeation flooding for tight oil

作　　者：丁彬 熊春明[2] 耿向飞[1,2] 管保山 潘竟军[3] 许建国 董景锋[3] 张成明[4] DING Bin;XIONG Chunming;GENG Xiangfei;GUAN Baoshan;PAN Jingjun;XU Jianguo;DONG Jingfeng;ZHANG Chengming(Key Laboratory of Oilfield Chemicals,CNPC,Beijing 100083,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;Xinjiang Oilfield Company,PetroChina,Karamay 834000,China;Jilin Oilfield Company,PetroChina,Songyuan 138000,China)

机构地区：[1]中国石油天然气集团有限公司油田化学重点实验室,北京100083 [2]中国石油勘探开发研究院,北京100083 [3]中国石油新疆油田公司,新疆克拉玛依834000 [4]中国石油吉林油田公司,吉林松原138000

出　　处：《石油勘探与开发》2020年第4期756-764,共9页Petroleum Exploration and Development

基　　金：中国石油科技重大专项“页岩油有效动用关键技术及应用”(2019E-2607);中国石油勘探开发研究院学科建设项目“非常规油藏高效波及控制与驱油技术研究”(yjxk2019-12)。

摘　　要：针对致密油开发“水注不进去,油采不出来”的关键技术难题,以二苯醚类水溶性(双子)表面活性剂为水相外壳,C10—C14直链烃类化合物为油相内核,利用微乳液制备技术研制纳米流体增渗驱油体系,并开展实验评价体系特征及提高采收率机理。研究表明,该体系具有5大特征:①“小尺寸液”特征,体系平均粒径小于30 nm,可大幅降低注水启动压力梯度,有效进入并扩大微纳米孔喉基质波及体积;②“小尺寸油”特征,体系在流动条件下将原油打散成“小尺寸油”,大幅提高原油在微纳米孔喉基质中的渗流能力与驱替效率;③双相润湿特征,体系与亲水、亲油界面接触角分别为(46±1)°和(68±1)°,可在储集层复杂润湿条件下有效发挥毛细作用;④高表界面活性特征,体系与新疆某致密油界面张力为0.001~0.010 mN/m,可有效提高微纳米孔喉基质洗油效率;⑤破乳降黏特征,体系对反相乳化的新疆某致密油破乳降黏率大于80%,可提高原油在储集层和井筒中的流动性。该体系可用于致密油储集层压裂驱油增产、降压增注补充地层能量、驱替与吞吐提高原油采收率等领域,为致密油有效动用与高效开发及持续提高采收率提供技术支撑。Tight oil reservoir development is faced with the key technical problem that"water cannot be injected and oil cannot be produced"yet.With the diphenyl ethers water-soluble(gemini)surfactants as water phase shell and C10–C14 straight-chain hydrocarbon compounds as oil phase kernel,a nanofluids permeation flooding system was prepared by microemulsion technology,and its characteristics and EOR mechanisms were evaluated through experiments.The system has the following five characteristics:(1)"Small-size liquid":the average particle size of the system is less than 30 nm,which can greatly reduce the starting pressure gradient of water injection,and effectively enter and expand the sweep volume of micro-nano matrix;(2)"Small-size oil":the system can break the crude oil into"small-size oil"under the flow condition,which can greatly improve the percolation ability and displacement efficiency of the crude oil in the micro-nano matrix;(3)Dual-phase wetting:the system has contact angles with the hydrophilic and oil-wet interfaces of(46±1)°and(68±1)°respectively,and makes it possible for capillarity to work fully under complex wetting conditions of the reservoir;(4)High surface activity:the interfacial tension between the system and crude oil from a tight oil reservoir in Xinjiang is 10-3–10-2 mN/m,indicating the system can effectively improve the displacement efficiency of oil in fine pore throats;(5)Demulsification and viscosity reduction:the system has a demulsification and viscosity reduction rate of more than 80%to inversely emulsified crude oil from a tight oil reservoir in Xinjiang,so it can improve the mobility of crude oil in the reservoir and wellbore.The system can be used to increase oil production by fracturing in tight reservoirs,replenish formation energy by reducing injection pressure and increasing injection rate,and enhance oil recovery by displacement and cyclic injection,providing key technical support for effective production and efficient development and recovery enhancement of tight reservoirs.

关 键 词：致密油 纳米流体 增渗驱油 体系特征 提高采收率 小尺寸液 小尺寸油 双相润湿 

分 类 号：TE357[石油与天然气工程—油气田开发工程]