高含硫气藏元素硫沉积对储集层的伤害

元素硫是高含硫气藏开发的有害物质。随着气井的投产，地层压力和温度沿径向不断降低，在气流达到或超过含硫饱和度时，元素硫将会从气流中析出，并在储集层岩石的孔隙或喉道中沉积下来，使得地层孔隙度和渗透率降低，严重时造成气井的停产甚至报废。在推导了元素硫沉积对储集层伤害的模拟模型基础上，分析了在高含硫气藏的开发过程中，元素硫沉积的特征及对储集层物性的伤害情况，发现元素硫在地层中的沉积主要在离井筒较近的范围之内，且沉积量沿径向由井筒向地层深处逐渐减小；沉积于孔隙的元素硫对储集层的伤害也主要在该区域之内，越靠近井筒伤害程度越严重，且随着生产时间的延长。对储集层的伤害程度加速。图4表1参6

Formation damage from elemental sulfur deposition in sour gas reservoir

Reservoir pressure and temperature decrease radially to the borehole after the gas wells were put into production. Elemental sulfur is separated from gas stream and precipitate in the pores or channels if the gas stream is saturated with sulfur, which decreases the porosity and permeability or even completely plugs the flow channels of gas and leads to the closed in or abandonment of the gas wells. The paper presents a model to simulate the formation damage caused by elemental sulfur deposition, based on which the characteristics of elemental sulfur deposition and its damage to the formation properties were analyzed. The results show that the elemental sulfur mainly deposits in the near wellbore area and the deposition decreases radially from the wellbore to the formation. Formation damage is more serious in the area nearer to the wellbore and the damage increases with the production.