柴西地区复杂岩性核磁共振T_2截止值研究  

Research on NMR T2Cutoff of Complex Lithology in the West Qaidam Basin

作　　者：吴丰[1] 司马立强[1] 杨洪明 令狐松 田葱葱 

机构地区：[1]西南石油大学资源与环境学院,四川成都610500 [2]中国石油集团测井有限公司,陕西西安710021

出　　处：《测井技术》2014年第2期144-149,共6页Well Logging Technology

基　　金：中国石油重大科技专项(2011E-0305);国家科技重大专项(2011ZX05031-003-006HZ)

摘　　要：柴达木盆地西部地区储层岩性复杂,包括含岩屑砂砾岩、泥质砂岩、中高孔隙度低渗透率泥灰岩、藻灰岩、基质低孔隙度低渗透率裂缝型灰岩等类型,常用的核磁共振理论T2截止值在柴西地区不适用.选取5种不同类型岩石样品各若干,根据岩样的实际情况结合行业标准确定合理的离心压力,采用离心法测定了不同岩性的T2截止值.柴西地区岩石的核磁共振五截止值普遍低于理论值;且不同的岩性有较大差别,一般砂砾岩T2截止值为1.8～3.0ms,泥质砂岩为5～10 ms,中高孔隙度低渗透率泥灰岩为3ms左右,藻灰岩为10～25 ms,低孔隙度低渗透率裂缝型灰岩为10～30 ms.造成这种偏低和差异现象的主要原因包括岩石的矿物成分、颗粒粒度大小、孔隙结构等.The reservoir lithology in the west Qaidam basin is complex, the lithology includes debris glutenite, argillaceous sandstone, high porosity and low permeability muddy limestone, algal limestone, fractured limestone with low porosity ＆ low permeability matrix, and so on. The theoretical NMR T2 cutoff is not applicable in the west Qaidam basin. The article selects some samples of 5 different types of rock to determine the reasonable centrifugal pressure by combining the actual samples and industry standard. Then determined is the T2 cutoff of rocks with different lithology by centrifugal method. The experiment results show that, the NMR T2 cutoff values are generally lower than the theoretical value; and rocks with different lithologies have bigger differences, generally, the T2 cutoff of debris glutenite is 1.8-3.0 ms, argillaceous sandstone is 5-10 ms, high porosity ＆ low permeability muddy limestone is about 3 ms, algal limestone is 10-25 ms, fractured limestone with low porosity ＆ low permeability matrix is 10- 30 ms. This phenomenon is mainly caused by rock mineral composition, granule size and pore structure, et al.

关 键 词：测井解释 核磁共振 T2截止值 岩性 柴达木盆地 

分 类 号：P631.84[天文地球—地质矿产勘探]