高含硫气藏硫沉积机理研究

硫沉积是高含硫气藏开发过程中普遍存在而又必须解决的关键难题之一。高含硫气藏硫沉积机理研究是研究高含硫气藏硫沉积预测技术、准确掌握地层硫沉积动态以及指导高含硫气藏高效开发的基础。在分析高含硫气藏气体开采过程中硫化氢含量变化规律基础上，引入无机化学中化学反应平衡理论，建立了由多硫化氢分解析出元素硫的地层含硫饱和度计算方法，以W气田为例，预测了地层压力下降到不同程度时距离井筒不同距离处由多硫化氢分解析出元素硫的量，并与利用解析模型计算的总析出量进行了对比。结果表明，高含硫气藏开发过程中，在硫化氢含量变化不大的情况下，由多硫化氢（H₂Sx＋1）分解析出的硫的量占总析出量的比例很小，即物理沉积是硫沉积的主要方式，从而进一步完善了元素硫的沉积理论，为认识和解决高含硫气藏开发过程中在地层发生元素硫沉积、合理高效地开发高含硫气藏奠定了坚实的理论基础。

SULFUR DEPOSITION MECHANISM OF THE GAS RESERVOIRS WITH HIGH SULFUR CONTENT

Sulfur deposition is the one of the key issues，which universally exists and must be solved in the process of development of the reservoirs with high sulfur content.The research on the sulfur deposition of the reservoirs with high sulfur content is the foundation of studying sulfur deposition prediction technology of the reservoirs with high sulfur content，precisely handling sulfur deposition dynamic performance in formations and guiding effective development of the reservoirs with high sulfur content.On the basis of analyzing H2S content change law in the process of developing the gas in the gas reservoirs with high sulfur content，the chemical reaction equilibrium theory of inorganic chemistry is introduced to establish formation sulfur saturation calculation method，taking W gas field as example，the amount of element sulfur precipitated from polysulfide decomposition in different distance from wellbore when the formation pressure decreases to different degree is predicted，and comparison between the amount and the total precipitated amount calculated with analytic model is conducted.Result indicates that，in the process of the development of the reservoirs with high sulfur content，under the condition of minor sulfide content change，the sulfur content precipitated from polysulfide （H₂Sx+1） takes very low proportion of total precipitated amount，i.e.，physical deposition is the main way of sulfur deposition，so as the deposition theory of element sulfur is further improved，the solid foundation of recognizing and solving element sulfur deposition in the process of developing the gas reservoirs with high sulfur content and reasonably and effectively developing the reservoirs with high sulfur content is placed.