青海木里三露天天然气水合物预判气测录井应用研究

Application of Gas Logging to Natural Gas Hydrate Prognosis in Sanlutian of Muli,Qinghai

气测录井以其可以灵敏、快速监测钻遇不同地层赋存烃类气体信息的优势而成为常规油气和非常规油气资源勘查的一种成熟技术手段。考虑到当钻具研磨赋存有天然气水合物的岩层时势必会导致其分解释放大量烃类气体并被气测录井仪器灵敏有效地监测,首次尝试利用气测录井方法在我国陆域冻土区——青海木里三露天天然气水合物调查区进行钻探实时预判,建立天然气水合物的野外现场实时预判方法。最后,以DK8-19钻孔为例说明气测录井实时预判方法的应用、存在的问题及建议。实际应用结果表明,单一利用气测录井方法实时预判天然气水合物层段与地质和分析测试综合认识结果的吻合度可达到85.71%,而将上述三种方法结合可进一步提高野外识别天然气水合物的准确度。

With the advantages of sensitive and quick monitoring hydrocarbon gases in different stratigraphies, gas logging has become a mature technology for exploring the conventional or unconventional oil and gas. Considering that while the drilling tool is grinding strata bearing gas hydrate, the gas hydrate could decompose and release numbers of hydrocarbon gases which can be sensitively monitored by gas logging, this paper tries to discuss and establish a real-time prognosis method to recognize gas hydrates in permafrost regions in Mull of Qinghal. Taking drillhole DK8-19 in Sanlutian coal field in Muli of Qinghai as an example, the application, problems and suggestions of this real-time prognosis through gas logging was discussed. The practical application shows that the goodness of fit between the result of singly using gas logging and that of combining geological analysis and testing is up to 85.71%, and the result of combining gas logging, geological analysis and testing will be better.