页岩岩心样品分析数据对比及其影响因素分析

近10年来,在对四川盆地川南地区下古生界上奥陶统五峰组—下志留统龙马溪组页岩气的勘探开发过程中,以及在与多家国际石油公司的页岩气合作评价中,针对含气页岩层段钻取了大量的岩心资料,并且在国内外不同的实验室都开展了页岩岩石矿物学、有机地球化学、岩石物理和含气性等方面的测试分析,积累了大量的页岩岩心分析数据。通过对比分析同一块样品或同一深度层段样品的分析结果,发现在不同实验室之间、不同分析方法之间,甚至在不同样品类型、不同取样方式和不同取样部位之间,有关分析数据都存在着较大的差异,由此影响到对页岩气储层的准确评价与页岩气勘探开发前景的客观认识。为此,在剖析若干分析数据质量问题实例的基础上,讨论确认了造成页岩岩心样品分析结果不一致的一些影响因素,如样品类型、取样部位、取样方法以及测试方法等。进而提出建议:为了减少上述因素所带来的影响,应该在页岩油气行业内,从页岩岩心的处理到标准化取样制样和测试分析,建立起一套系统和规范化的致密岩石分析流程与普遍适用的实验方法。结论认为,必须重视页岩岩心样品分析的质量问题,除了实验室内部应该建立起一套科学的分析质量保证与控制体系(QA/QC)之外,重视和接受来自...

Correlation of shale core analysis results and its influencing factors

Over the last decade, a large number of gas-shale cores have been acquired during the exploitation of the Lower Paleozoic Wufeng-Longmaxi shale gas in the Southern Sichuan Basin, and in the joint appraisal of shale gas blocks in cooperation with several overseas international petroleum companies. Therefore, huge quantities of shale core data about shale mineralogy, geochemistry, petrophysics and gas content have been accumulated and measured in different labs at home and abroad. By correlating the core data from the same piece of sample or from the samples in the same intervals, it is found that there are obvious disparity with the analysis results from different labs, between different analytical methods, even from different types of samples, different ways of sampling, and different parts of the same sample, which certainly has an affect on the objective understanding of shale reservoirs and the exploitation prospect in this study area. Based on the case studies of several data quality issues, some influencing factors causing the inconsistency of the shale core analysis results are discussed, such as sample types, sampling location, sampling methods and test facility. In order to reduce the impact of these factors, it is suggested that a systematic and standardized analysis procedure and robust methods for tight rock analysis from the shale core handling to standardized sampling and testing should be put forward in shale oil and gas industry. It is concluded that attention to quality issues related with shale core analysis must be paid. In addition to the scientific analysis quality assurance and quality control set up inside the laboratory, the external quality assessment and feedback from data users are also an important way for promoting and improving the quality of core analysis.