一种精细控压钻井流动模型的研究与应用

为了提高高温深井控压钻进时的环空压力剖面计算精度,实现井底压力精细控制,基于水力学、传热学和流变学基本理论,采用黏温特性室内试验、Drillbench商业软件对比、井下环空压力实测数据验证等方法,建立了高温深井控压钻井精细流动模型。该模型充分考虑了环空温度分布、钻井液黏温特性、高温高压下的钻井液密度等因素,实现了压力温度耦合计算。现场应用表明,该模型的计算精度相比普通模型有了一定提高,绝对误差仅为0.2 MPa左右,为高温深井压力敏感储层的井下压力计算和环空压力控制提供了更好的技术手段。 

The Research and Application of a Fine MPD Flow Model

In order to improve the calculation accuracy of annulus pressure profile and realize fine calculation of bottomhole pressure,a fine MPD flow model was established for high temperature deep wells based on comprehensive research methods including hydraulics,heat transfer theory,rheological basic theory,viscosity-temperature characteristics,lab experiment,comparison with Drillbench software,verification by measured downhole annular pressure,etc.Factors such as annulus temperature distribution,drilling fluid viscosity-temperature characteristics,drilling fluid density characteristic under high temperature and high pressure were fully considered.This model realized the coupling calculation of pressure and temperature.Field application showed the accuracy of this model was higher than that of other models,with an absolute error of merely about 0.2 MPa.The model provided a better means of pressure calculation and annulus pressure control for pressure sensitive reservoirs in high temperature deep wells.