深水作业中钻井液在低温高压条件下的流变性

在深水钻井作业中,安全密度窗口非常窄,井下压力控制是面临的主要难题之一。随着水深的不断增加,环境温度随之降低,钻井液的黏度和切力随之升高;同时,由上千米隔水管内的钻井液所附加的静液柱压力使井底压力远大于浅水作业时相同井深的井底压力。这些因素的共同作用使得当量循环密度随之增加,进一步加大井底压力控制的难度。选择用于深水钻井的一种水基和一种合成基钻井液为研究对象,分别改变温度和压力等实验条件,利用FANN公司的ix77流变仪测量了钻井液在低温、高压下的流变参数,以此找出深水条件下钻井液流变性随温度和压力的变化规律。

Research on Drilling Fluid Rheology with Low Temperature and High Pressure in Deep Water Operation

When operating in deep water,to control the well bore pressure is difficult due to the narrow safety density window.The viscosity and gel strength of drilling fluid are increased with the temperature reduction,and the bottom hole pressure caused by the drilling fluid column in riser is high,so the surge pressures are more difficult to control. This paper highlights the effects of temperature and pressure on rheological properties of synthetic oil based drilling fluids and water base drilling fluids by the i...