高含硫地质环境钻井硫化氢气侵规律研究

Study on hydrogen sulfide gas cutting in high-sulfur geological environment

针对硫化氢的特殊物性,研究了硫化氢组分、气体偏差因子、硫化氢黏度等重要的物性参数对气侵两相流的影响。运用气液两相流的原理和方法,建立了硫化氢气侵时环空气液两相流流动模型,研究了硫化氢气侵时井底压力和井筒压力的特征及变化规律,并用实例对理论模型进行了验证,进而分析了气侵时钻井液密度、钻井液黏度、井口回压、井底气侵速率等重要参数对井底压力的影响规律。在确定钻井液附加密度时,应充分考虑硫化氢气侵对井底压力和井筒动压的影响规律,其结果会更加合理。

The effects of the physical properties of H2S, including composition of H2S, gas error factor and viscosity of H2S on gas-inversion two-phase flow were investigated. The model for gas-liquid two-phase flow was developed by applying the two-phase flow principle while H2S cuts the borehole. The property and changing law of the pressure at bottom hole and borehole were investigated. The model was applied to a real well case. The effects of some parameters, including the density and viscosity of drilling fluid, back pressure at wellhead and the rate of gas cutting at bottom hole, on the pressure of bottom hole were analyzed. The affecting of H2S cutting on the pressure of bottom hole and borehole should be considered when the density of drilling fluid is added, which brings a more reasonable result.