多级暂堵转向重复压裂技术探索及在河南油田的应用

Exploration and application of multi-stage temporary plugging turning to repeated fracturing technology in Henan oilfield

重复压裂改造是维持老井产能的一种重要手段,但随着重复压裂次数增多,增油效果和有效期大幅度下降。暂堵转向重复压裂可以在老缝中实现新的裂缝,沟通更大的泄油面积,从而提高油井产量。结合河南油田重复压裂改造实际需要,根据裂缝转向机理物模实验,认识了转向裂缝的造缝延伸机理。实验结果表明,重复压裂裂缝以沿老缝延伸为主,实现老缝强制转向的地应力差界限为8 MPa。现场试验效果表明,评选出的高强度、低伤害裂缝转向剂,成功实现了裂缝的多级转向,应用效果较好。

Repeated fracturing is an important means to maintain the productivity of old wells, however, with the increase of repeated fracturing, the effect of oil increase and the effective period of oil production will de-crease greatly. The temporary plugging turning to repeated fracturing can realize new fractures in the old fractures and communicate with larger oil drainage area, thus improving oil well production. According to the physical model experiment of fracture steering mechanism, the mechanism of fracture building and extension is understood. The experimental results show that the repeated fracturing fractures are mainly extended along the old fractures, and the limit of the stress difference of the forced turning of the old fractures is 8 MPa. Field test results show that the selected high strength and low damage fracture steering agent has successfully achieved multistage fracture steering, and the application effect is good.