油气藏评价与开发 ›› 2022, Vol. 12 ›› Issue (3): 468-476.doi: 10.13809/j.cnki.cn32-1825/te.2022.03.009

• 页岩气勘探 • 上一篇    下一篇

松辽盆地沙河子组页岩孔隙结构表征——基于低场核磁共振技术

李楚雄1,2(),申宝剑1,2,卢龙飞1,2,蒋启贵1,2,潘安阳1,2,陶金雨1,2,丁江辉1,2   

  1. 1. 中国石化石油勘探开发研究院无锡石油地质研究所,江苏 无锡 214126
    2. 页岩油气富集机理与有效开发国家重点实验室,江苏 无锡 214126
  • 收稿日期:2020-11-03 出版日期:2022-06-26 发布日期:2022-06-24
  • 作者简介:李楚雄(1992—),男,硕士,助理研究员,从事非常规石油地质研究。地址:江苏省无锡市蠡湖大道2060号无锡石油地质研究所,邮政编码:214126。E-mail: lichuxiong.syky@sinopec.com
  • 基金资助:
    国家自然科学基金企业创新发展联合项目“深层页岩有效储层形成保存机理及定量表征研究”(U19B6003-03-02);国家自然科学基金项目“复杂构造—成岩背景下海相页岩有机孔隙演化与晚期差异保存研究”(41972164);中国石化科技部项目“页岩孔隙精细表征及流体动态监测技术研究”(P20059-8)

Pore structure characterization of Shahezi Formation shale in Songliao Basin: Based on low-field nuclear magnetic resonance technology

LI Chuxiong1,2(),SHEN Baojian1,2,LU Longfei1,2,JIANG Qigui1,2,PAN Anyang1,2,TAO Jinyu1,2,DING Jianghui1,2   

  1. 1. Wuxi Research Institute of Petroleum Geology, Sinopec Exploration and Production Research Institute, Wuxi, Jiangsu 214126, China
    2. State Key Laboratory of Mechanism and Effective Development of Oil and Gas Enrichment in Shale, Wuxi, Jiangsu 214126, China
  • Received:2020-11-03 Online:2022-06-26 Published:2022-06-24

摘要:

为了表征松辽盆地沙河子组页岩微观孔隙结构,选取沙河子组9个页岩样品开展了饱和与干燥状态下的核磁共振T2测试,同步进行了岩石物性测试和场发射扫描电镜观察,系统分析了核磁共振T2弛豫特征,孔隙类型与分布特征,对比了核磁孔隙度与气测法孔隙度的差异。结果表明:沙河子组页岩样品的核磁共振T2谱以单峰型为主,弛豫时间较短,孔隙直径主要分布在10~1 000 nm;孔隙类型以纳米级无机孔为主,有机孔和微裂缝相对不发育;扣除基底信号后计算的核磁共振孔隙度分布在0.68 %~3.66 %,与He(氦)孔隙度具有较好的匹配关系;孔隙度较小的样品更容易受岩石基质背景信号影响而造成测试结果的相对误差。总体认为,核磁共振技术能够准确分析低孔、低渗页岩样品的孔隙度和孔径分布,但需要注意页岩中有机质和黏土矿物束缚水产生的核磁信号干扰。

关键词: 页岩, 核磁共振, 孔隙度, 孔径分布, 孔隙类型

Abstract:

In order to characterize the micro pore structure of Shahezi Formation shale in Songliao Basin, nine shale samples from the lower part of the Shahezi Formation in the Songliao Basin were selected to carry out NMR T2 tests in saturated and dry conditions, and simultaneous petrophysical testing with field emission scanning electron microscope observation. The T2 relaxation characteristics, pore types and distribution characteristics were systematically analyzed. And the difference of porosity measured by the NMR method and the gas method was compared. The results show that the NMR T2 spectrum of the shale samples from the Shahezi Formation is dominated by a single peak type with shorter relaxation time, and the pore diameter is mainly distributed in the range of 10~1 000 nm. The pore types are mainly nano-scale inorganic pores, and the organic pores and microfracture generally underdeveloped. The NMR porosity calculated after deducting the base signal is 0.68 %~3.66 %, which has a good matching relationship with Helium porosity. The samples with smaller porosity are more likely to be affected by the background signal of rock matrix, resulting in the relative error of test results. In generally, the nuclear magnetic resonance technology can accurately analyze the porosity and pore size distribution of low porosity and low permeability shale samples, but attention should be paid to the NMR signal interference caused by organic matter and clay mineral bound water.

Key words: shale, nuclear magnetic resonance, porosity, pore size distribution, pore type

中图分类号: 

  • TE121