低渗裂缝型气藏斜井压裂技术研究

中原油田户部寨气田是一个低渗致密裂缝型砂岩气藏，生产井多为斜井，投产需要进行压裂改造，前期效果不理想的原因是气藏的天然裂缝和斜井压裂中产生的人工多裂缝的双重作用会造成支撑缝长、裂缝宽度和导流能力降低，易使支撑剂过早发生桥塞，产生砂堵，从而影响压裂效果。以往压裂施工中为消除多裂缝的影响采取的主要措施是前置液加入大量的粉砂，但对裂缝导流能力有不利影响，使得压裂效果较差。为此，分析了斜井压裂多裂缝产生的原因，集成应用避射、射孔优化、支撑剂段塞、变排量、变黏度施工等技术，有效地降低了大斜度井压裂所产生的弯曲摩阻，控制了裂缝条数，同时又实现了大斜度井压裂不加粉砂和环空注入方式的突破，简化了压后作业程序，并以部1-14井大斜度定向井压裂施工为例进行了压裂效果分析，取得了好的成果。

A STUDY ON FRACTURING TECHNOLOGY OF DEVIATED WELLS IN LOW-PERMEABILITY, FRACTURED GAS RESERVOIRS

Hubu-zai gas field in Zhongyuan oil field is a low-permeability, compacted and fractured sandstone field. Most wells in this field are deviated ones, which need to be fractured before production. Due to the combined effect of natural and man-made fractures, long fracture length, reduced fracture width and flow conductivity are resulted, causing earlier bridge plug of the proppant and sand plug. In fracturing operations before, great amount of silt sand were added into the ahead fluid to remove such effect, which has side-effect to the fluid conductivity of the fractures. Therefore, technologies of perforation optimization, proppant slug, varying discharging rates and varying fluid viscosity, etc. were applied to reduce the bending friction during the fracturing process in deviated wells, so that the number of fractures was controlled. Meanwhile, breakthrough was achieved in realization of no silt-sand fracturing and annular injection. In this paper, practical application of such technology in Bu1-14 well was also analyzed.