NaCl、NaCl—CaCl_(2)、CaCl_(2)盐水作基液对压井液性能影响的实验研究

EXPERIMENT AND STUDY OF THE INFLUENCE OF BASE FLUID ON KILLING FLUID BY RESPECTIVELY USING NaCl,NaCl-CaCl_(2) OR CaCl_(2) BRINE AS THE BASE FLUID

为了保护储层 ,在修井、试井等作业中 ,普遍采用清洁盐水作压井液。文章通过进行浓度比较、聚合物盐析、岩块浸泡、有机质析出、乳化及动态流动模拟等一系列实验 ,从储层保护技术的角度 ,研究分析了NaCl、Na Cl—CaCl2 、CaCl2 盐水作压井液基液 ,对所配制的压井液性能的影响。认为选择NaCl与CaCl2 的混合液作为压井液基液 ,比用单纯的NaCl、CaCl2 盐水作压井液基液具有可减少用盐量、降低矿化度、抑制大盐晶体形成、相对减少沥青质析出、且在岩石表面形成的高分子覆盖膜较薄、与原油乳化程度较低等优点 ,对配制有利于保护储层的压井液更为合宜。文章同时也提供了研制和评价保护储层优质压井液的实验研究方法。

In order to protect reservoir,the clean brine is generally used as the killing fluid in the workover and well test operations.In this paper,through a series of experiments,such as the comparison of concentration,the salting-out of polymer,the soak of rock block,the liberation of organic matter,the emulsification and simulation of dynamic flow,etc.,and in view of reservoir protection,the influence of the base fluid on the performance of killing fluid by using NaCl,NaCl—CaCl 2 or CaCl 2 brine as the base fluid of killing fluid is studied and analyzed.It is considered that,as compared with NaCl or CaCl 2 brine,Using mixed fluid of NaCl and CaCl 2 as the base fluid of killing fluid is of many advantages (the salt volume and the salinity can be reduced;the formation of big salt crystalline can be inhibited;the liberation of asphaltene can be relatively reduced and the macromolecule covering film formed on the rock′s surface is relatively thin and the degree of the emulsification with crude oil is relatively low,etc.),so it is more suitable for preparing the killing fluid favorable to reservoir protection.The methods of experiment and study for developing and evaluating the high-quality killing fluid for protecting reservoir are presented also in this paper.