A simple and inexpensive technique for assessing contamination during drilling operations
A simple and inexpensive technique for assessing contamination during drilling operations
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DOI：
10.1002/lom3.10159
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发表时间：
2017-02-01
影响因子：
2.7
通讯作者：
Wagner, Dirk
中科院分区：
文献类型：
--
作者：
Friese, Andre;Kallmeyer, Jens;Wagner, Dirk
地下勘探依靠钻探。正常情况下，钻井需要钻井液渗入钻芯。钻井液含有来自地表的非本土物质和微生物，因此它的存在使样本不适合进行微生物和许多其他分析。由于渗透无法避免，因此评估污染程度以确定未受污染的样品进行地质微生物调查是至关重要的。为此，通常将示踪剂混合到钻井液中。在过去的钻井作业中，使用了各种示踪剂，每种示踪剂都有特定的优点和缺点。对于微球，主要问题是价格高，这限制了它们的使用仅限于抽查或只需要少量钻井液的钻井作业。在这里，我们提出了一种改进的微球示踪剂方法，它使用具有与以前使用的微球示踪剂相似的荧光颗粒浓度的水性荧光颜料分散体。然而，它的成本低了四个数量级，即使在大型手术中也可以更自由地使用。国际大陆钻探计划(ICDP)在印度尼西亚苏拉威西的Towuti湖和墨西哥的Chalco湖的两次钻探活动中成功测试了其在深部钻探活动中的适用性。示踪剂的定量只需要荧光显微镜或流式细胞仪。后者允许在几分钟内直接在现场获得高分辨率数据，并且只需很少的努力，与传统的示踪方法相比，大大减少了样品处理时间。这种方法为钻井活动中的污染评估提供了一种廉价、快速但功能强大的替代技术。
Subsurface exploration relies on drilling. Normally drilling requires a drilling fluid that will infiltrate into the drill core. Drilling fluid contains non-indigenous materials and microbes from the surface, so its presence renders a sample unsuitable for microbiological and many other analyses. Because infiltration cannot be avoided, it is of paramount importance to assess the degree of contamination to identify uncontaminated samples for geomicrobiological investigations. To do this, usually a tracer is mixed into the drilling fluid. In past drilling operations a variety of tracers have been used, each has specific strengths and weaknesses. For microspheres the main problem was the high price, which limited their use to spot checks or drilling operations that require only small amounts of drilling fluid. Here, we present a modified microsphere tracer approach that uses an aqueous fluorescent pigment dispersion with a similar concentration of fluorescent particles as previously used microsphere tracers. However, it costs four orders of magnitude less, allowing for a more liberal use even in large operations. Its applicability for deep drilling campaigns was successfully tested during two drilling campaigns of the International Continental Drilling Program (ICDP) at Lake Towuti, Sulawesi, Indonesia, and Lake Chalco, Mexico. Quantification of the tracer requires only a fluorescence microscope or a flow cytometer. The latter allowing for high-resolution data to be obtained directly on-site within minutes and with minimal effort, decreasing sample processing times substantially relative to traditional tracer methods. This approach offers an inexpensive, rapid, but powerful alternative technique for contamination assessment during drilling campaigns.