超临界二氧化碳钻井技术

Supercritical CO_2 Drilling Technology

当温度和压力分别达到31.10℃、7.38 MPa及以上时,CO2成为超临界状态,超临界CO2具有类似于液体的密度,而其粘度又比空气和氮气大,可以驱动井下动力钻具旋转破岩,并携带岩屑,形成超临界CO2钻井技术。超临界CO2钻井具备破岩速度快、油气层保护好、驱替效率高等优势,对于非常规油气藏开发具有明显优势。超临界CO2钻井与连续管钻井技术相结合,应用于压力欠平衡钻井和压力衰竭地层前景广阔。介绍了超临界CO2物理特征、超临界CO2钻井技术流程及其技术优势,最后阐述了超临界CO2钻井技术的研究进展及发展趋势。

When the temperature and pressure are higher than 31.10℃and 7.38MPa respectively, CO2 becomes into su-percritical state, the density of supercritical CO2 is similar to that of liquid, but the viscosity is higher than that of air and nitrogen gas, so it can drive the down-hole motor working and carry the cuttings out of the wellbore, which comes into being supercritical CO2 drilling technology.Supercritical CO2 drilling technology has the advantages of fast rock breaking speed, good gas and oil protection and high displacement efficiency, especially has the obvious advantages in the unconventional oil and gas reservoirs development.There are broad prospects for the application of combination of supercritical CO2 drilling and coiled tubing drilling technology in the pressure under balance drilling and pressure depletion formation.The paper in-troduces the supercritical CO2 technology about its physical characteristics, drilling process and the technical advantages as well as the related research progress and development trend.