基于压力的马氏漏斗黏度在线检测方法

Research on On-line Detection Method of Marsh Funnel Viscosity Based on Pressure

针对马氏漏斗黏度手动测量方法存在的工作量大、测量精度低、监测不连续等问题,从马氏漏斗黏度检测的原理、结构、算法等方面研究钻井液的在线检测过程,基于液位高度与液柱压力的关系,提出了一种钻井液马氏漏斗黏度的在线检测方法,并研制了一套实验装置。通过仿真模拟和中原油田钻井现场试验,验证了测试系统的准确性,系统精度达到±1 s。综合分析钻井液马氏漏斗黏度的影响因素,从溢流口形状、漏斗改造工艺和液位检测精度等方面优化在线检测方法,实验装置的钻井液密度测量误差低于3%,黏度测量误差低于2%。提出的马氏漏斗黏度在线检测方法及其实验装置可较好完成对常规钻井液的密度和马氏漏斗黏度的在线检测,具有较好的适应性和较高的自动化程度。在满足检测精度的前提下,在线检测方法和实验样机可较好代替现场人工检测,提高了油田的智能化水平。

An online method of measuring Marsh funnel viscosity was presented and a set of online measurement device developed to overcome the problems existed in field manual measurement of Marsh funnel viscosity,such as heavy workload,low measuring precision and measuring discontinuity.In developing the online measuring method,the online measurement process was studied from several aspects,such as the principle of the Marsh funnel viscosity measurement,the structure of the Marsh funnel and algorithm of calculating of viscosity measured with the new instrument.The relationship between the height of the liquid level in the funnel and the pressure of the liquid column is used to calculate the funnel viscosity.The accuracy of the new instrument was verified through analog and emulation,and field experiment in Zhongyuan Oilfield,the precision of the instrument was determined to be±1 s.By comprehensive analyses of the factors affecting the measurement of funnel viscosity of drilling fluids,the online measurement method was optimized in several aspects,such as the shape of the outlet,the modification technique of the funnel and detection of the liquid level.Measurement error caused by density of the drilling fluid is less than 3%,and the error by viscosity of the drilling fluid is less than 2%.This method and the instrument can be used to realize online measurement of the viscosity of the liquid drilling fluids,and have good applicability and high degree of automation.Satisfying the need of precise measurement of the funnel viscosity of drilling fluids,the online measurement method and the instrument can be used to replace the manual measurement presently in use,improving the intelligence level of oilfield operations.