基于CFD-DEM的直井多暂堵球运移规律及封堵效率研究

Research on the Transportation Law and Blocking Efficiency of Multi-Temporary Plugging Balls in Vertical Wells Based on CFD-DEM

摘要: 投球暂堵转向压裂技术是有效改造多产层油气藏的重要手段，但在垂直井下暂堵球的运移行为和封堵效率方面存在较大不确定性。基于CFD-DEM的耦合方法，模拟暂堵球在垂直井单簇内运移及转向封堵过程，探究投放位置与孔眼相对距离、投放位置与孔眼相对角度，射孔流量比对运移规律及封堵效率的影响。结果表明：暂堵球位置是影响暂堵球成功坐封的主导因素，投放位置距离孔眼越近封堵率越高，相对孔眼侧位投放易导致暂堵球错过射孔区域，高射孔流量比下暂堵球受朝向拖曳力更强，相较于低射孔流量比下封堵效率更高。

Abstract: Ball drop temporary plugging and steering fracturing technology is an important means to effectively modify multi-layer reservoirs, but there are large uncertainties in the transportation behavior and blocking efficiency of temporary plugging balls in vertical wells. Based on the coupling method of CFD-DEM, we simulate the transportation and steering plugging process of temporary plugging ball in a single cluster of vertical wells, and investigate the effects of the relative distance between the placement position and the borehole, the relative angle between the placement position and the borehole, and the ratio of the injection flow rate on the transportation pattern and the plugging efficiency. The results show that the position of the plugging ball is the dominant factor influencing the success of the plugging ball, the closer the placement position is to the borehole, the higher the plugging rate is, the lateral placement relative to the borehole will easily cause the ball to miss the injection area, and the plugging ball will be dragged more strongly by the direction of the high injection flow rate, which will result in a higher plugging efficiency compared to that of the low injection flow rate.