页岩气水平井井筒积液流动规律研究——以C01井区为例

目的 C01井区页岩气井开采中后期，天然能量不足，井筒积液普遍，准确实时识别积液位置困难，导致排水采气工艺实施效果欠佳，故需针对井筒积液流动进行研究。方法 基于C01井区积液现状，在Beggs持液率模型的基础上，使用生产数据及井筒流型对持液率模型进行修正，从而可以准确地实时识别积液位置，与生产测井剖面实测数据进行对比，验证了修正模型的准确性；基于实际页岩气井钻井数据建立了页岩气井的全井段几何模型，实现了气液两相流动模拟，分析了井型对积液位置的影响。结果 修正的持液率模型在页岩气井中应用时，其平均相对误差为6.66%,可以为现场提供较为准确的积液位置识别；数值模拟结果表明，下倾型和上倾型页岩气水平井由于能量衰减导致造斜段易形成积液。结论 应用修正的持液率模型计算积液位置显示，页岩气水平井造斜段易形成积液；数值模拟结果与修正的持液率模型应用计算结果符合，通过使用预测的生产数据可以对井筒积液位置进行预判。

Research on the flow law of shale gas in horizontal wellbore: Taking C01 well area as an example

ObjectiveIn the middle and late stages of shale gas well development in C01 well area, natural energy is insufficient and wellbore fluid accumulation is common. As a result, the implementation effect of drainage gas recovery technology is not good, it is necessary to study the wellbore fluid flow. MethodsBased on the current situation of fluid accumulation in C01 well area, the Beggs fluid holdup model is revised by using production data and wellbore flow patterns. It is compared with the measured data of the production logging profile, the accuracy of the modified model is verified. Besides, based on the actual shale gas wellbore data, a geometric model of the entire shale gas well was established that realized the simulation of gas-liquid two-phase flow and analyzed the influence of well type on the location of fluid accumulation. ResultsWhen the modified liquid holdup model is applied in shale gas wells, the average relative error is 6.66%, which can provide a more accurate identification of the location of fluid accumulation on site. Numerical simulation results show that down-dip and up-dip shale gas horizontal wells tend to form fluid accumulation in the deflection section. ConclusionsThe application of the modified liquid holdup model to calculate the liquid accumulation position shows that the shale gas horizontal well is prone to liquid accumulation in the deflection section. The results of numerical simulation are consistent with the calculated results of the modified liquid holdup model. And the location of wellbore fluid accumulation can be predicted by using the predicted production data.