限流法压裂射孔方案优化设计

PERFORATION OPTIMIZATION DESIGN FOR OPERATION OF LIMITED ENTRY FRACTURING TECHNOLOGY

张士诚 王世贵 张国良 张有才 董建华

Zhang Shicheng Wang Shigui Zhang Guoliang Zhang Youcai Dong Jianhua

石油大学, 北京昌平 102600 大庆油田井下地质研究所, 黑龙江大庆 163453

限流法压裂是低渗透多油层油藏挖潜改造的主要方法,它设计的关键是各层射孔方案的优化。传统的方法是根据各小层的厚度确定射孔数,再由射孔数按比例计算施工过程中各层进液量和砂量,没有综合考虑各层的物性对改造规模和射孔数的影响,以及施工过程中井筒、炮眼和裂缝内摩阻等对各层进液量的影响。建立了限流法压裂施工过程中各层流量随时间、地层物性和射孔数变化的数学模型,与裂缝几何参数模型联立可进行射孔方案优化设计。通过大庆长垣内部油田22口井的试验,取得了较好的增产效果和经济效益。

Limited entry fracturing technology is a chief method used to stimulate low permeability muti-layer reservoirs. The key point is how to optimize perforation process for different layers. Perforations are determined according to the formation thickness in conventional way. Then the fracturing fluid and sand volume is calculated proportionally based on the number of perforations. Therefore, the influence of characteristic nature of different layer on the operation scale and perforations is not considered. It is also not considered that the well bore; the perforations and the friction affect fluid entry volume in different layer during operation. A mathematic model to calculate limited entry volume changes with time, formation characteristic and perforations has been set up. Combining the model above and the model of fracture geometry can carry out the optimization design. The field test of 22 wells in Daqing Chang-huan shows a better production improvement.

10.3969/j.issn.1000-7393.2000.02.017