海陆过渡相页岩岩相特征及测井识别方法  

Lithofacies characteristics and logging identification method of marine-continental transitional shale

作　　者：曾静波 高衍武 石志强 张凤生 何羽飞 李星涛 ZENG Jingbo;GAO Yanwu;SHI Zhiqiang;ZHANG Fengsheng;HE Yufei;LI Xingtao(China National Logging Corporation,Xi’an 710077,Shaanxi;PetroChina Coalbed Methane Company Limited,Beijing 100028)

机构地区：[1]中国石油集团测井有限公司,陕西西安710077 [2]中石油煤层气有限责任公司,北京100028

出　　处：《长江大学学报（自然科学版）》2024年第4期40-49,共10页Journal of Yangtze University(Natural Science Edition)

基　　金：中国石油“十四五”前瞻性基础性项目“海陆过渡相页岩气地震储层预测及测井评价技术研究”(2021DJ2002);中国石油集团测井有限公司科技项目“重点勘探领域测井解释评价核心技术攻关”(CNLC2022-08B02)。

摘　　要：与海相页岩相比,海陆过渡相页岩具有更复杂的岩性及更强的非均质性,常规的基于矿物组分的三端元岩相划分方法和常规测井资料无法精细而准确地反映岩性及非均质性的变化。以鄂尔多斯盆地东缘的大宁吉县地区二叠系山西组2段3亚段(P_(1)s^(3)_(2))页岩为研究对象,利用X衍射、岩心薄片、有机碳等实验资料实现以“沉积环境指示+有机质+矿物组分”为核心的有利页岩岩相划分,通过岩心与测井资料的相互标定,总结出不同页岩岩相的测井响应特征,在选取敏感测井参数的基础上应用贝叶斯判别法建立不同页岩岩相的测井识别方法。研究结果显示:①目的层主要发育有3大类7小类11个细分页岩类型,其中富有机质硅质页岩、富有机质混合质页岩具有较好的有机质、物性、含气性及脆性指标,是最优的页岩类型,其次为富有机质黏土质页岩及中有机质黏土质页岩,并且同类页岩中厌氧型页岩各项参数指标相对更优;②通过选取密度中子包络面积、声波电阻率包络面积、伽马去铀伽马差值、深浅电阻率比值、脆性指数、钍元素含量共6条敏感测井曲线建立贝叶斯判别方程,能准确有效地识别研究区P_(1)s^(3)_(2)的不同页岩岩相类型。研究结果可为海陆过渡相页岩储层后续参数精细评价及压裂选层提供有利技术支撑。Compared with marine shale,marine and continental transitional shale has more complex lithology and stronger heterogeneity.Conventional three-terminal lithofacies classification method based on mineral components and conventional logging data cannot accurately reflect the changes of lithology and heterogeneity.Taking the shale of 3rd sub-member,2nd member of Permian Shanxi Formation(P_(1)s^(3)_(2))of Daning-Jixian area in the eastern margin of Ordos Basin as the research object,based on X-ray diffraction,core thin sections and organic carbon to realize the favorable shale lithofacies division with“sedimentary environment indication+organic carbon+mineral composition”as the core.Through the mutual calibration of core and logging data,the logging response characteristics of different shale lithofacies are summarized.On the basis of selecting sensitive logging parameters,Bayes discriminant method is used to establish logging identification methods for different shale lithofacies.Among the findings:①There are 3 major categories,7 subcategories and 11 subdivided shale types in the target layer,among which organic-rich siliceous shale and organic-rich mixed shale are the best shale types with good indexes of organic matter,physical property,gas content and brittleness,followed by organic-rich clay shale and organic-medium clay shale,and the parameters of anaerobic shale in the same type of shale are relatively better.②By selecting six sensitive logging curves including density neutron envelope area,acoustic resistivity envelope area,gamma deuranium gamma difference,deep and shallow resistivity ratio,brittleness index and thorium content,Bayes discriminative equation is established,which can accurately and effectively identify different shale facies types in P_(1)s^(3)_(2)of the study area.The research results provide favorable technical support for the fine evaluation of subsequent parameters and fracturing formation selection of Marine and continental transitional shale reservoirs.

关 键 词：海陆过渡相 鄂尔多斯盆地 岩相划分 测井响应 测井识别 

分 类 号：P631.84[天文地球—地质矿产勘探] TE132.14[天文地球—地质学]