高含硫气藏硫沉积预测热力学模型

在高含硫气藏开发过程中,伴有元素硫的析出、沉积、气相组成变化和沉积硫堆积在孔隙喉道污染地层等特殊现象.其中硫微粒的沉积将降低地层孔隙度和渗透率,影响气藏的产能,严重的硫沉积甚至会导致气井报废.为了能够提高含硫气藏开发的预见性,建立安全开发模式,运用化学热力学理论建立了气液固三相相平衡硫沉积预测热力学模型预测硫的沉积,在此模型基础上对比计算、分析了硫化氢含量对硫沉积的影响.得出以下结论:在压力和温度一定的条件下硫的沉积量与硫化氢的含量成反比,在组成和温度一定的条件下压力越低硫的析出量越大.

Thermodynamics model for predicting the sulfur deposition in the gas reservoirs of high H2S content

The gas reservoirs of high H2S content belong to special gas reservoirs. In the development of this kind of gas reservoirs,there are some special phenomena of the precipitation and deposition of sulfur,the change of gas phase compositions,and the damage of the deposited sulfur to the gas reservoirs,and so on.The deposition of sulfur would decline the porosity and permeability of the gas reservoirs and decrease the productivity of the gas reservoirs.In order to improve predictability of developing the reservoirs and establishing a safe development mode,the thermodynamics model for predicting the sulfur deposition in the gas reservoirs of high H2S content is presented based on gas-liquid-solid three-phase equilibrium.Based on the model,the effect of hydrogen sulfide content on the sulfur deposition is analyzed.It is shown that under the condition of the same temperature and pressure,the quantity of sulfur deposition will decrease with the increase of hydrogen sulfide content;under the condition of the same composition and temperature,the quantity of sulfur deposition increases with the declining of pressure.