高含硫碳酸盐岩酸压气井硫沉积规律研究

Elemental Sulfur Deposited in Acid fractured Carbonate Sour Gas Wells

硫沉积是高含硫气藏开发过程中的常见现象,不仅给生产设备带来严重的安全隐患,也容易造成地层堵塞,是影响该类气藏安全高效开发的重要因素之一,但目前国内外对地层中硫沉积条件的研究都是基于简单的静态环境,预测结果往往与实际存在较大差异。在综合考虑基岩和裂缝渗流空间特征以及气流水动力对析出的硫颗粒运移影响的基础上,建立了描述碳酸盐岩酸压气井生产过程中硫沉积预测模型。结果表明:流体水动力是建立硫沉积预测模型必须考虑的因素之一;硫在基岩中的沉积主要发生在距井底和靠近裂缝面相对较小的区域,且沿井底向裂缝纵深方向和垂直于裂缝向外延伸的方向上,硫沉积量和沉积速率均呈递减下降的趋势;硫在裂缝中的沉积距井底距离越近,硫沉积量越大且沉积速率相对较快;无论是基岩或裂缝中的硫沉积,随着生产时间的延长,其沉积速率呈加速变化趋势。

It＇s a common phenomenon that elemental sulfur deposits in formations, which not only brings serious damages to production equipment, but also easily plugs permeability channels. This is one of key factors that affect the safe and effective development of sour gas reservoirs. Because of modeling on just static environments and neglecting the behavior of gas current hydrodynamic force to elemental sulfur particles, the results predicted by many models had great errors compared to the actual data. This paper presents a new theory model which considers the effects of gas current hydrodynamic force on elemental sulfur particles transporting. Research shows that： （1） gas velocity is a factor that must be considered while modeling; （2） elemental sulfur occurred mainly in a relatively small region close to the well bottom and the fractures; （3） the quantity and settling rate of elemental sulfur deposition decrease progressively along the well bottom to the fractures; （4） regardless of elemental sulfur deposited in the matrix or the fractures, the setting rate increases with production time.