硫沉积对高含硫气藏产能影响数值模拟研究

高含硫气藏是一类具有高危性和特殊性的酸性气藏，硫微粒的析出、运移以及沉积是该类气藏特殊渗流特征之一。沉积的硫微粒会占据孔隙空间，在孔喉处堵塞孔隙，改变孔隙结构，最终引起硫沉积区内储层渗透率的降低，从而影响气藏的开发效果。为此，在对硫沉积机理深入研究的基础上，引入空气动力学理论，建立高含硫气藏硫微粒运移、沉积数学模型，模拟研究了硫沉积对均质气藏和非均质气藏产能的影响。结果认为：高含硫气体初始溶解元素硫是该类气藏发生硫沉积的重要条件之一；硫沉积使得气藏的稳产时间缩短、采出程度降低、气藏递减期缩短以及递减期内的递减率增加等；低渗透气藏和非均质性强的地层，其硫沉积对气藏开发的影响很大。

A NUMERICAL SIMULATION STUDY ON THE IMPACT OF SULFUR DEPOSIT ON PRODUCTIVITY OF SOUR GAS RESERVOIRS

Gas reservoirs with high sulfur content belong to high risk and special sour gas reservoirs. Dropout, transportation and deposit of sulfur particles are characteristics of such reservoirs. These deposited sulfur particles occupy the pore volume, plug the pore throats, change the pore structure and finally reduce reservoir permeability. In this paper, aerodynamics was introduced to set up a mathematical model for transportation and precipitation of sulfur particles in sour gas reservoirs to simulate the impact of sulfur deposit on productivity of homogeneous and heterogeneous gas reservoirs. It was summarized that the initially solved sulfur element is one of the key requirements for later deposit, which shortens the stable production period of the gas reservoir, reduces the recovery rate, and accelerates production rate decrease, etc.; and the impact of sulfur deposit is much more significant in low-permeability and highly heterogeneous formation.