川西新场气田蓬莱镇组气藏储层的敏感性研究

The sensitivity of the gas reservoirs in the Penglaizhen Formation of the Xinchang gas field, western Sichuan

关键词:  采收率  储层损害  敏感性  速敏  水敏  盐敏  碱敏

Key words:  recovery  formation destruction  sensitivity  velocity sensitivity  water sensitivity  salt sensitivity  alkali sensitivity

摘要:

浅层气田提高低渗气层的采收率,降低储层的损害程度非常重要。浅层气因其产层埋深浅,地层压力低,储层物性较差等,生产作业中更易造成损害,形成伤害后使得单井产能急剧降低,甚至不能产出天然气。因此,开展必要的储层损害研究显得尤为重要。笔者通过大量的敏感性实验分析,认为新场气田蓬莱镇组浅层气藏储层为弱速敏、中等水敏,临界盐度为(0.35~0.45)×10⁴mg/L气藏,临界pH值在7~8之间变化,并提出对降低各种敏感性的作业条件。

Abstract:

It is very important to increase the recovery of low permeable gas reservoirs and reduce the degree of formation destruction. In shallower gas pools, the burial depth of pay zones is relatively shallow and formation pressure is also relatively low. The poor reservoir quality may easily result in the formation destruction during production. After being damaged, the productivity of a single well decreases sharply, or the well can't produce any natural gas at all. Numerous experimental studies of sensitivity suggest that the reservoirs in the shallow gas pools of the Penglaizhen Formation within the Xinchang gas field, western Sichuan are characterized by weak velocity sensitivity and moderate water sensitivity. The critical salinity values equal to (0.35-0.45)×10⁴ mg/L and critical pH values range between 7 and 8. The operation conditions are also proposed in the paper for the purpose of reducing different sensitivities.