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| 基于先验信息约束的核磁共振数据反演新方法 |
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金国文1,2,谢然红1,2,徐红军3,郭江峰1,2,高伦1,2
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(1.中国石油大学(北京)油气资源与探测国家重点实验室,北京 102249;2.中国石油大学(北京)地球探测与信息技术北京市重点实验室,北京 102249;3.中国石油勘探开发研究院,北京 100083)
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| 摘要: |
| 针对核磁共振(NMR)测井T2谱短弛豫组分反演不精确的问题,提出一种基于先验信息约束的NMR反演新方法(ILT+)。首先利用积分变换方法直接从核磁共振原始回波数据中提取先验信息,具体为利用指数双曲正弦变换方法(ESHT)计算T2谱锥形区域面积,利用梅林变换方法(MT)计算T2的ω次幂的均值(〈Tω2〉);然后将提取的先验信息作为约束条件构造新的目标函数并反演求解。数值模拟和实际井资料处理结果表明:同时施加两种先验信息作为约束条件的ILT+方法综合了单独施加时的ILT+方法的优点,提高了T2谱短弛豫组分的反演精度。新方法对于小孔占优的致密砂岩、页岩等非常规储层的NMR回波数据反演具有广阔的应用前景。 |
| 关键词: 核磁共振 反演 积分变换 先验信息 短弛豫 |
| DOI：10.3969/j.issn.1673-5005.2019.02.006 |
| 分类号::P 631 |
| 文献标识码:A |
| 基金项目:国家自然科学基金项目(41674126)；中国石油天然气股份有限公司科学技术研究与技术开发项目(2016B-03) |
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| A new method of NMR echo data inversion constrained by priori information |
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JIN Guowen1,2, XIE Ranhong1,2, XU Hongjun3, GUO Jiangfeng1,2, GAO Lun1,2
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(1.State Key Laboratory of Petroleum Resources and Prospecting in China University of Petroleum(Beijing), Beijing 102249, China;2.Key Laboratory of Earth Prospecting and Information Technology in China University of Petroleum(Beijing), Beijing 102249, China;3.PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China)
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| Abstract: |
| A new inversion method of nuclear magnetic resonance (NMR) logging constrained by priori information (ILT+) was presented for the inaccuracy of NMR inversion at short relaxation times. The priori information was computed directly from NMR echo trains using integral transforms. Specially the T2 tapered areas were computed using exponential hyperbolic sine transform (ESHT) and the mean value of the ω-th moment of T2 was computed using Mellin transform (MT). The numerical simulation and well data processing showed that the new method simultaneously constrained by two priori information synthesized the advantages of the new method constrained by single priori information, and improved the inversion accuracy of T2 spectrum at short relaxation times. This new method has broad application prospects for NMR data inversion in unconventional reservoirs such as tight sandstone and shale which usually contain more small pores. |
| Key words: nuclear magnetic resonance inversion integral transform priori information short relaxation times |
