页岩油井压裂示踪剂裂缝检测技术研究

Research on Fracture Detection Technology ofFracturing Tracer for Shale Oil Wells

为了对大庆古龙地区页岩压裂效果进行评价,采用压裂示踪剂裂缝检测技术研究压裂过程中裂缝的开启及缝高和缝宽情况,确定水平井压裂各段簇改造效果。利用压裂示踪剂具有放射性的特性,根据压裂设计中支撑剂的用量计算出示踪剂的用量,在压裂的不同泵注阶段伴注不同的示踪砂,示踪砂随支撑剂一同填充于裂缝缝隙之中,通过压后测井施工与后期数据处理分析获得裂缝缝高及缝宽。现场应用结果表明,根据井眼周围支撑剂分布等资料,计算出单段裂缝高度为13.9m,其中单簇裂缝高度最高为10.2m,相比致密岩缝高20~30m还有很大的扩展空间;裂缝平均宽度为0.41cm,最大宽度为1.233cm。建议页岩油井在压裂过程中可适当调节施工排量和压裂液浓度,以提高裂缝高度;采用大孔径射孔弹来提高裂缝宽度,形成均匀展布的裂缝网络,增大裂缝与储层的接触面积。

To evaluate the fracturing effect of shale in the Gulong area of Daqing,the fracture detection technology of fracturing tracer was used to study the opening,height,and width of fractures during fracturing,and determine the stimulation effect of each fracturing cluster in horizontal wells.Based on the radioactive properties of the tracer,the amount of the tracer is calculated according to the amount of proppant in the fracturing design,various tracing sand is injected at different pumping stages of the fracturing,and the tracing sands are filled in the fractures with the proppant.The height and width of the fractures are obtained through post-fracturing logging,and post-data processing and analysis.The field application results show that according to the data of proppant distribution around the hole,the fracture height of a single section is 13.9m,of which the highest fracture height of a single cluster is 10.2m,which has a large space compared with the tight rock fracture height of 20-30m.The average fracture width is 0.41cm,and the maximum is 1.233cm.It is suggested that the discharging and fracturing fluid concentration may be properly adjusted to improve the fracture height during the fracturing of shale oil wells.Large-aperture perforating charges may increase the fracture width,form a uniform distributed fracture network,and increase the contact area between the fracture and the reservoir.