气体钻井条件下泥页岩水侵规律实验研究

Experiment on Water Invasion in Shale Sequence during Gas Drilling Process

通过在室内模拟气体钻井条件下泥页岩地层的温度和压力,分别对气体钻井钻遇地层出水条件下的水侵规律和气体钻井转水基钻井条件下的水侵规律进行实验研究,并建立相应条件下的水侵距离与时间的关系,从而对相应条件下泥页岩地层的水侵范围和坍塌范围进行预测,分析这2种情况下水侵距离与时间的关系。结果表明两者均呈现出初期水侵速度较快、中后期逐渐变缓的特征。对比2种情况下的水侵距离与时间的关系,前者的水侵速度要比后者的水侵速度慢得多,同样水侵穿透5 cm的距离时,前者所用时间是后者的350倍左右。

In this paper, the experiments are subjected to simulate the variations of temperature and pressure in the shale sequence during the gas drilling process. We try to get the behavior of water invasion when the water flow out from the shale sequence during the gas drilling process and gas drilling adjusted to waterbased drilling. A correlation between water invasion distance and time is established to predict the water invasion scope and collapse range. We use this correlation to simulate two cases about water invasion distance and time,and find out that the early water invasion is fast and the late becomes slow gradually. The water invasion speed for the former case is slower than that for the latter one if the correlation between water invasion distance and time for two cases of are contrasted. The time for water invasion in the former case is 350 times than that for the latter in the 5cm water invasion distance.