Perforation Completion Optimization For Injection Well

Perforation is the last step of well completion, so injection well perforation completion has great influence on water absorbing capability. Factors that affect water flow in near wellbore zone include perforation size, depth, density, phase and pollution that caused by drilling and perforation, etc. Due to the complicacy of perforation layout, water absorbing capability of sandstone reservoir completed by perforation is much more complicated than that of conventional open hole wells.Perforation completion optimization for injection well is to apply Finite Element Method to conduct numerical simulation to determine the effect of perforation parameters on water absorbing capability, and analyze the response of water absorbing capability to each parameter, and then predict the injection wells'water absorbing capability under various perforation condition. In order to avoid the serious damage of perforation on formation and improve the productivity, the determination of perforation negative pressure is the key point of perforation optimization design. Over low negative pressure may affect perforation cleaning and formation protection, and over high negative pressure may cause sand out, formation collapse, casing damage or package failure, etc. So new method that using Finite Element Method and non-Darcy flow law is researched to determine minimum negative pressure that can ensure clean perforation, and perforated rock stress-strain model is established to get maximum negative pressure that can keep perforation stable and prevent sand out.This injection well perforation parameter prediction theoretical method provides a new way to improve poor formation's water absorbing capability and mitigate over fracture pressure injection. Optimized perforation can increase laminated reservoir's productivity and reduce injection pressure. It not only can be applied in initial completion stage to optimize parameters, but also can help to adjust parameters for existing injection wells to...