井下含水率传感器表面处理技术  

Surface treatment technology of downhole water cut sensor

作　　者：杨清海[1,2] 高伟 魏松波[1] 于翔[3] 于川[1] 石白茹 杨兴国[2] 沈翘楚 许箕磊 YANG Qinghai;GAO Wei;WEI Songbo;YU Xiang;YU Chuan;SHI Bairu;YANG Xingguo;SHEN Qiaochu;XU Jilei(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;Jilin Oilfield Oil&Gas Engineering Research Institute,Songyuan 138000,China;China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]吉林油田油气工程研究院,吉林松原138000 [3]中国地质大学,北京100083

出　　处：《石油勘探与开发》2022年第6期1242-1251,共10页Petroleum Exploration and Development

基　　金：国家自然科学基金基础科学中心项目“数字经济时代的资源环境管理理论与应用”(72088101);中国石油天然气集团有限公司科学研究与技术开发项目“智能分层注采工程技术研究”(2021ZG12);国家重点研发计划/政府间国际科技创新合作重点专项“能源与水纽带关系及高效绿色利用关键技术”(2018YFE0196000)。

摘　　要：基于电导式含水率传感器结构、原理和工作环境分析,揭示传感器金属电极在井下长期服役时因井液冲蚀、电化学腐蚀和油液污染等因素综合作用而发生早期失效的过程,提出利用掺硼金刚石(Boron-doped diamond,BDD)薄膜进行电极表面改性处理的方法,提高薄膜改性电极的服役性能。采用热丝化学气相沉积法沉积BDD薄膜,依次调整掺硼浓度、优化沉积时间并进行氟化处理,综合优化BDD薄膜的耐磨损性、耐电化学腐蚀性和疏油性。研究表明:掺硼浓度为6×10^(-3)时薄膜的高耐磨性和耐电化学腐蚀性赋予改性电极良好的耐冲蚀和抗腐蚀能力,摩擦系数和磨损率较因瓦合金分别降低92%和78%,低频阻抗模值大于1×10^(4)Ω·cm^(2);沉积时间8 h制备的BDD薄膜沉积晶粒尺寸较小且分布均匀,表现出良好的微纳结构,最利于提高改性电极的疏油性能,在模拟井液中的接触角达102°。BDD薄膜改性电极在模拟工况下的应用实践表明,改性电极表现出优异的耐冲蚀磨损、耐电化学腐蚀性以及抗油污黏附能力,可实现电导式含水率传感器在井下苛刻工况下的长期稳定工作。Based on the structure,working principle,and working conditions of conductance water cut sensor,it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well fluid erosion,electrochemical corrosion,and oil pollution during its long-term service in the downhole.A technology for electrode surface treatment is proposed using boron-doped diamond(BDD)films to improve the service performance of the modified electrode.The hot wire chemical vapor deposition method was adopted to fabricate BDD film,the boron doping concentration and deposition time were optimized,and fluorination treatment was applied to improve the wear resistance,electrochemical corrosion resistance,and oleophobic property of the BDD film comprehensively.The results showed that BDD film with boron doping concentration of 6×10^(-3)exhibited high wear resistance and good electrochemical corrosion resistance,and endowed the modified electrode with superior erosion resistance and corrosion resistance.The friction coefficient and wear rate of BDD modified electrode were 92%and 78%lower than those of Invar alloy,also,the low-frequency impedance modulus value of the modified electrode was higher than 1×10^(4)Ω·cm^(2).The BDD film prepared with a deposition time of 8 h had a favorable micro-nano structure owing to small grain size and uniform distribution.Such morphology was conducive to enhancing the oleophobic performance of the modified electrode,and its contact angle in the simulated well fluid was high to 102°.The engineering applicability of BDD film modified electrode under simulated working conditions indicated that,the modified electrode had excellent comprehensive performances of erosion resistance,electrochemical corrosion resistance and oil adhesion resistance,and can realize the long-term stable operation of the conductance water cut sensor under harsh downhole conditions.

关 键 词：含水率传感器 表面处理 掺硼金刚石薄膜 耐冲蚀磨损性 耐电化学腐蚀性 疏油性 

分 类 号：TE257[石油与天然气工程—油气井工程]