水平井分段多簇压裂缝间干扰研究

水平井分段多簇压裂在现场得到了广泛运用,其压裂过程中普遍存在缝间干扰现象。缝间干扰有助于形成复杂裂缝网络以提高储层导流能力,但是也会导致起裂困难,甚至形成砂堵。因此有必要对分段多簇压裂的缝间干扰问题进行研究。对此,基于弹性力学建立了分析多簇裂缝诱导应力的数学模型,从起裂压力、裂缝宽度、簇间距等多方面研究了缝间干扰对水平井分段多簇压裂施工的影响。模拟结果显示,诱导应力会导致起裂压力升高、裂缝变窄,严重时将造成压裂施工失败。通过进行分析,给出了起裂过程及延伸过程中缝间干扰的影响关系。分析认为,利用缝间干扰提高改造体积时应当控制簇间距防止对压裂施工造成负面影响。研究结论对优化水平井分段多簇压裂设计具有指导意义。

The Effects of Crack Interaction in Multi-stage Horizontal Fracturing

Multi-stage horizontal fracturing has been widely used in the field with the inevitable crack interaction. Crackinteraction is conducive to initiation and extension of fractures,which forms complex fracture network and improves reservoirconductivity. However,crack interaction also has adverse effects on hydraulic fracturing resulting in poor stimulation. Basedon the theory of elasticity,mathematical models are established to study the effects of crack interaction in multiple clusterfractures,from the aspects of initiation pressure,fracture width and the position of fracture. The study shows that it is hardto get successful stimulation with serious crack interaction because the phenomenon such as change of fracture width resultingfrom crack interaction. To get the relationship of cluster space,fracture height and crack interaction,a sensitivity analysis isconducted. The result indicates that the cluster space should be reasonable to avoid the adverse effects of crack interaction. Thestudy result contributes to the optimization of the stimulation of multiple stages horizontal well.