测井多参数两向量法识别页岩气地质“甜点”

发布时间：2018-10-09 09:24

【摘要】：为了给页岩气水平井地质导向钻井目标层的优选提供地质依据,以四川盆地威远地区下寒武统筇竹寺组页岩地层为研究对象,提出了测井多参数两向量法识别页岩气地质"甜点"的方法。该方法首先利用测井曲线计算页岩有机碳含量、脆性指数和含气饱和度;然后优选敏感反映好、中、差页岩气层的测井地质参数,结合试井资料构建页岩气层样本集;再由好、差两类页岩气层样本计算第一、第二判别向量C、K及其对应的综合指标R_1、R_2,建立好、中、差页岩气层判别图版和分类特征投影函数F;进而根据判别结果优选出页岩气地质"甜点"作为地质导向钻井的目标层,并进行了现场检验。结果表明:(1)据该区筇竹寺组页岩地层测井地质参数拟合/改进的有机碳含量、脆性指数、含气饱和度的公式可用于相关参数的计算;(2)依据页岩气层判别图版与特征函数F确定页岩气地质"甜点"层段判别标准所得到的结果直观可靠;(3)现场实践中,采用该方法实时准确划分了页岩地层的目标层和导向标志层,准确率由采用传统的多元线性逐步判别法的72.6%提高到了现在的87.4%。结论认为,该方法应用于研究区页岩气地质"甜点"的判别,所得结果合理可靠、准确度高。
[Abstract]:In order to provide the geological basis for the optimal selection of the target layers in the guiding drilling of shale gas horizontal wells, the shale formation of the Lower Cambrian Qiongzhusi formation in Weiyuan region, Sichuan Basin, is taken as the research object. This paper presents a method of identifying shale gas geology by logging multi-parameter two-vector method. The method firstly calculates shale organic carbon content, brittle index and gas saturation by logging curve, and then optimizes the logging geological parameters of the sensitive, medium and differential shale gas formations, and constructs the shale gas reservoir sample set based on the well test data. The difference between the two types of shale gas samples is the first, the second discriminant vector CnK and its corresponding comprehensive index, R _ 1 / R _ 2, are well established. According to the discriminant chart of differential shale gas reservoir and the feature projection function of classification, the shale gas geology "dessert" is selected as the target layer of geological guiding drilling according to the discriminant result, and the field inspection is carried out. The results are as follows: (1) according to the fitting / improving organic carbon content and brittleness index of the logging geological parameters of the shale formation of Qiongzhusi formation in this area, The formula of gas saturation can be used to calculate the relevant parameters; (2) the results obtained by determining the criteria of shale gas geological "dessert" section according to shale gas discriminant chart and characteristic function F are intuitionistic and reliable; (3) in the field practice, By using this method, the target layer and the guiding marker layer of shale formation are divided in real time and accurately, and the accuracy rate is improved from 72.6% of the traditional multivariate linear stepwise discriminant method to 87.4% of the present one. It is concluded that the method can be used to judge the shale gas geology "dessert" in the study area, and the results obtained are reasonable and reliable, and the accuracy is high.
【作者单位】： "油气藏地质及开发工程"国家重点实验室·西南石油大学;四川长宁天然气开发有限责任公司;
【基金】：国家重点基础研究发展计划(973计划)项目“页岩气水平井钻完井关键基础研究”(编号:2013CB228003)
【分类号】：P618.13

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