滤液密度在钻井液测试分析中的应用

Application of filtrate density in fluid test and analysis.

传统钻井液理论测定求算固相含量的过程,相关联的物理量多,不但程序复杂,而且蒸馏、计量、读取、滴定每个环节都可能出现误差,累积误差通常较大。在钻井液理论中引入滤液密度的概念,提出了用滤液密度来直观衡量钻井液矿化度的观点,推导出了用滤液密度求算未加重水基钻井液悬浮固相含量的数学公式,在施工现场测量了钻井液及其滤液密度后,就可用该数学式计算出固相含量,整个过程既不需要固相含量测定仪,也不需要对滤液进行滴定分析和计算,非常方便、快捷,并且通过实例介绍,证明用该推导的数学式计算的结果与传统测定法计算的结果基本一致。建议在施工现场绘制井深与钻井液密度、滤液密度关系曲线图,在此图上不但可以观察到钻井液总矿化度的变化情况,而且可直观显示出悬浮固相含量随井深的变化情况。探讨了如何在现场对滤液密度进行快速准确测定的问题。

There are many related physical parameters considered in calculating the solids content using traditional drilling fluid theory.Not only the program for calculating is complicated,but also errors may be produced in the every link of distillation,measure,reading and titration and usually have a higher accumulative error.For these reasons,the conception of filtrate density was introduced into drilling fluid theory,the viewpoint using filtrate density to visual judge the salinity of fluid directly was put forward and the formula of calculating the suspending solids content in unweighted water based fluid using filtrate density was deduced.In the field,the solids content can be calculated by the formula after fluid density and filtrate density being measured.The whole testing procedure is convenient and quick without solids content instrument,filtrate titration analysis and calculation.The case history prove the data from calculation formula was close to that from traditional method.It is suggested to draw the plot of well depth via fluid and filtrate density,in which the salinity change tendency of drilling fluid and suspending solids content in different well depth can be observed.Finally,it was discussed how to measure the filtrate density quickly and accurately in the field.