天然气水合物岩心带压转移装置研制与现场试验

Research and Field Test of a Pressure-Stabilizing Transfer Device for Natural Gas Hydrate Samples

天然气水合物对温度压力条件的变化很敏感,温度或压力的扰动会导致烃类气体逸出,固体水合物趋于崩解。因此,在钻探获取天然气水合物岩心后,为将岩心在带压情况下转移和保存,必须配备一套与保温保压取心工具配套的岩心转移装置。在研发保温保压筒与转移仓之间压力平衡和岩心转移技术后,设计了一套采用液压缸拉动与压差推动岩心管相结合的岩心带压转移装置。室内和现场试验证明,带压转移装置控制灵活、耐压能力强、密封性好,能够实现天然气水合物岩心从水合物赋存区向实验室的带压转移,可为国内天然气水合物的自主勘探取样提供技术支撑。

Natural gas hydrate is an ice-like crystalline substance formed by natural gas and water at high pressure and low temperature.It is extremely sensitive to changes in temperature and pressure.If the disturbed hydrocarbon gas escapes due to changes in temperature and pressure,the hydrate will tend to disintegrate in a potentially explosive manner,thereby destabilizing the borehole.Therefore,after drilling of natural gas hydrate samples,a core transfer devices must be carefully aligned with the coring tools to transfer samples to the laboratory,it is important to maintain pressure during the transfer and preservation of the the samples of natural gas hydrates.After many years of research on the stabilization of pressure in the natural gas hydrate thermal pressure sampling tools and equipment and core transfer technologies,one core pressure-holding transfer device was developed with hydraulic cylinder to pull and push the pressure sampling tube.Both indoor and field tests demonstrated that the pressure-holding transfer device could be operated flexibly,and had high pressure resistance,good sealing performance.Thus is could successfully transfer the natural gas hydrate samples under pressure from the sampling zone to test lab.This new technique provided technical support for independent exploration of natural gas hydrate sampling in China.