| 摘要: |
| 根据核磁共振弛豫机制,基于三维数字岩心技术建立一种估算砂岩核磁共振横向弛豫(T2)谱的新方法。采用过程模拟法重建砂岩三维数字岩心,通过Delaunay剖分将砂岩微观孔隙结构划分为多个四面体孔隙单元,再用几何方法和Monte Carlo方法相结合求出每个孔隙单元的表面积与体积之比(S/V),进而获得砂岩模拟的核磁T2谱。经过大量模拟试验筛选参数,减小计算误差。考虑单峰态和双峰态核磁T2谱,模拟结果和实验结果基本吻合。该方法有助于研究粒度分布、孔隙结构等对岩石核磁共振响应的影响。 |
| 关键词: 核磁T2谱 数字岩心 过程模拟法 Delaunay剖分 Monte Carlo方法 |
| DOI：10.3969/j.issn.1673-5005.2017.01.007 |
| 分类号: |
| 文献标识码:A |
| 基金项目:国家自然科学基金项目(41374124,2);国家科技重大专项(2011ZX05014-004-002H) |
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| A new method of estimating NMR T2 spectrum of sandstone |
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YAN Weichao1, SUN Jianmeng1, CUI Likai1, YAN Guoliang2
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(1.School of Geosciences in China University of Petroleum, Qingdao 266580, China;2.Research Institute of Petroleum Exploration ＆ Development-Northwest, PetroChina, Lanzhou 730020, China)
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| Abstract: |
| Based on nuclear magnetic resonance(NMR)relaxation mechanism and three-dimensional digital core technology, a new method of estimating the spectrum of sandstone transverse relaxation time (T2) is established. A process-based method was used to reconstruct 3D digital rock models of sandstone. Sandstone microstructures were divided into tetrahedral pore units using Delaunay tessellation. Considering the geometry and using a Monte Carlo approach, the surface-to-volume ratio (S/V) of each pore unit was calculated, and then the T2 spectrum of sandstone could be simulated. After a large number of simulations, suitable parameters were selected in order to reduce calculation errors. Unimodal and bimodal T2 spectrum were considered; both results agreed well with laboratory tests. This new method is helpful in studies of different NMR response effects with varying grain sizes or pore structures. |
| Key words: NMR T2 spectrum digital core process-based method Delaunay tessellation Monte Carlo method |
