元坝高含硫气藏超深水平井完井技术研究及实践

RESEARCH AND PRACTICE OF ULTRA-DEEP HORIZONTAL WELL COMPLETION TECHNOLOGY IN HIGH-SULFUR GAS RESERVOIR OF YUANBA

元坝长兴组气藏属于超深、高温、高压、高含硫碳酸盐气藏,水平井完井的经济性与安全性矛盾非常突出,作业工况及井下条件复杂,风险和效率是该类气井完井需要考虑的重点。为此,通过大量的理论研究、模拟计算、室内实验、现场试验,形成了元坝高含硫气藏超深水平井完井技术。Ⅰ-Ⅱ类较多的礁相储层,以衬管完井方式为主,Ⅰ-Ⅱ类较少的叠合区、滩相储层,底水较为发育区域,采用射孔完井;完井材质选用4C类镍基合金;完井工具采用具有自平衡功能的井下安全阀、具备可回收功能的锚定密封插管封隔器;完井管柱采用复合油管,原则上不设计坐放短节、不采用伸缩节;通过优化封隔器坐封位置减少镍基合金套管使用长度。通过以上措施,既能满足酸化及长期安全生产要求,便于后期作业,又极大程度降低了完井成本,为该区的勘探开发提供了重要的技术支持。

There are many characteristics in Yuanba Changxing Carbonate Rock formation, such as ultra-deep, high temperature, high pressure and high-sulfur and so on. Which have the conspicuous contradiction between safety and economy about the completion of horizontal well. Facing the difficulties of connection leakage,the failure packer, working conditions, the complex downhole conditions, the high requirements of equipment and instrument performance, the risk and efficiency in such gas well should be considered. Through large numbers of theoretical research, analog calculation, laboratory experiment and field test, the ultra-deep horizontal well completion technologies were formed in YuanBa high-sulfur gas reservoir. I-II class has more reef reservoir, it uses the liner completion; I-II class has less superposition area, beach facies reservoirs with the development bottom water, it uses the perforation completion. The completion materials selected 4C Ni-base alloy, the completion tool used subsurface safety valve of self-balancing and anchoring sealed tube packer with recoverable features. Completion pipe string used composite tubes without landing nipple and expansion joint. By optimizing the location of the packer setting and reducing the length of nickel-base alloy casing, the requirements of long-term acidification and safety production could be met and the completion costs were greatly reduced.