考虑非平衡过程元素硫沉积对高含硫气藏储层伤害研究

元素硫沉积是高含硫气藏开发有别于常规气藏开发的一个重要研究内容.当地层压力下降时,元素硫溶解度下降使其沉积下来,沉积的元素硫会堵塞地层,从而降低地层孔隙度和渗透率.为了定量研究硫沉积对地层孔隙度和渗透率的影响,首先建立了元素硫沉积的伤害模型,然后利用该模型对一个实际高含硫气藏开发时由于元素硫沉积引起的地层孔隙度、渗透率和沉积含硫饱和度的动态变化进行了计算求解.通过实例计算发现:地层渗透率越低时越容易发生硫沉积,且硫沉积主要在井筒附近发生,当生产时间越长时,硫沉积的量越多,从而对地层的伤害越严重.

Reservoir damage caused by elemental sulfur deposition to high sulfur content gas reservoirs with the consideration of non-equilibrium process

The studies on elemental sulfur deposition are the important task for the development of high sulfur content gas reservoirs, and it is different from the development of common gas reservoirs. The solubility of elemental sulfur will reduce and sulfur will deposit when the formation pressure decreases. The sulfur deposition will damage the formation and decrease the porosity and permeability of formation. In order to quantitatively study the effect of sulfur deposition on formation porosity and permeability, the model of damage caused by elemental sulfur deposition is established firstly, and then based on the model the dynamic changes of porosity, permeability and sulfur saturation caused by sulfur deposition during the development of a high sulfur content gas reservoirs are calculated. The example calculation results show that the sulfur deposits easily in low permeability formation, and the deposition occurs mainly near the well bore. The damage increases with the increase of sulfur deposition volume and the production time.