陆地天然气水合物孔底冷冻取样方法  

Sampling for Land Gas Hydrates by Hole Bottom Freezing

作　　者：郭威[1] 孙友宏[1] 陈晨[1] 张祖培[1] 

机构地区：[1]吉林大学建设工程学院,长春130026

出　　处：《吉林大学学报（地球科学版）》2011年第4期1116-1120,共5页Journal of Jilin University：Earth Science Edition

基　　金：科技部国际合作与交流专项(2007DFR60100);中国地质调查局项目(1212010818055);吉林大学基本科研业务费项目(200903199)

摘　　要：如何获得品质优良的原状样品成为探明陆地天然气水合物赋存条件与储量的关键技术之一。在分析天然气水合物热物理性质和温压特性的基础上,采用主动式降温的方法,通过外部冷源在孔底降低水合物岩心温度,降低水合物的临界分解压力,抑制水合物分解,获得水合物保真样品:据此提出了天然气水合物孔底冷冻取样方法。设计的取样器总体结构由单动机构、控制机构和制冷机构组成,其工作原理主要为孔底冷冻岩心和地表取心,同时分析计算了取样器冷冻岩心所需的能量。通过钻探取样试验钻获冷冻岩心,证明天然气水合物孔底冷冻取样方法能够实现孔底冷冻岩样。该方法可以应用于天然气水合物保真取样。In-situ sampling techniques are crucial to keep hydrate samples intact for characterizing the occurrence conditions and reserves of the gas hydrates in permafrost land.Having taken into account the thermophysical characteristic and the temperature-pressure dependence of gas hydrates,we have developed a borehole bottom freezing technique for gas hydrate sampling.This technique can significantly reduce the required sampling pressure and prevent decomposition of the hydrate samples by means of an external cold source which freezes the hydrate cores at the bottom of borehole.The gross structure of freezing sampler is consist of single action,control mechanism and freezing mechanism.The two elementary principles are freezing core by hole bottom and achieving the sample on the surface are analyzed,which analyses the required energy that freezing core for the sampler.The borehole bottom freezing sampling was tested by a trial of core drilling.Success in retaining freezing samples demonstrates that this technique can be applied to obtain freezing samples from the borehole bottom,creating a novel approach for development of in-situ hydrate corers.

关 键 词：天然气水合物 陆地勘探 孔底冷冻 取心钻探 

分 类 号：TE244[石油与天然气工程—油气井工程]