长兴组生物礁气藏水侵早期识别及调整对策

Adjustment countermeasures and recognition of early water invasion in Changxing Formation biohermal gas reservoir

元坝油田长兴组气藏为发育底水的复杂礁滩体高含硫气藏。气藏开发过程中,发生水侵会导致气井产能降低,影响气藏最终采收率,开展气藏早期水侵识别,有利于提前采取治水措施。文中结合气藏地质特征,深入分析了物质平衡方法、生产动态判别方法、产出水的矿化度判别方法、试井监测识别法等水侵识别方法的适用性,并进行优选。利用研究成果,成功识别了2口气井存在水侵,及时有效地调整了气井的生产制度,延长了气井的无水产气期。

The gas reservoirs of Changxing Formation in Yuanba gas field are characterized by complex reef-flat facies, bottom water and high sulfur. The water invasion in the process of gas reservoir development can reduce the gas reservoir recovery and seriously influence gas production. Therefore, the recognition of early water invasion is beneficial to the water control measures. According to the practical geological character of gas reservoir, the adaptability evaluation of the methods such as material balance, production performance, the salinity of water monitoring, well test and so on, were analyzed and optimized. Using the research results, two gas wells with water invasion were successfully identified; timely and effective adjustment of gas wells production system extended the no water stage of gas wells.