Experimental Study and Field Application of Fiber Dynamic Diversion in West China Ultra-deep Fractured Gas Reservoir

摘要

Although a new technology of fiber diversion was introduced to hydraulic fracturing for ultra-deep sandstone formation, the operation is not always effective. This paper focused on the fracture reorientation mechanism and the relationship between injection pressure and fracture diversion according to large-scale physical simulation for fiber diversion in lab. The test results show that: firstly, the volume of fiber-based fluid is an important factor affecting fracturing diversion. If less fluid is designed, it would block original fractures inadequately. On the other hand, more fiber will result in sealing the open hole completely and fail to generate fracture diversion. Secondly, fracture initiation pressure after fiber frac fluid pumping can be used to evaluate diversion effectiveness. Higher level means lager reorientation angle. In the two-stage perforation, two fractures are initiated at different perforated wellbore depths. This validates the technology of fiber fracturing to create a better vertical coverage in the thick layer without mechanical packer. What we can learn from test results will help guide fiber diversion designing and evaluate corresponding fracture network in ultra-deep reservoir where great production contributed to natural fracture system, for example Dabei and Keshen gas fields in the Tarim Basin located in Western China.