新疆石油地质 ›› 2020, Vol. 41 ›› Issue (5): 550-556.doi: 10.7657/XJPG20200506

• 油气勘探 • 上一篇    下一篇

修武盆地下寒武统荷塘组海相页岩孔隙特征

郭春礼1(), 杨爽1(), 王安东1, 章双龙2, 祁星2   

  1. 1.东华理工大学 a.核资源与环境国家重点实验室;b.地球科学学院,南昌 330013
    2.江西省煤田地质勘察研究院,南昌 330001
  • 收稿日期:2020-06-01 修回日期:2020-06-22 出版日期:2020-10-01 发布日期:2020-10-10
  • 通讯作者: 杨爽 E-mail:1418253657@qq.com;yangshuang18@ecut.edu.cn
  • 作者简介:郭春礼(1993-),男,河南商丘人,硕士研究生,地质工程,(Tel)18236259983(E-mail)1418253657@qq.com
  • 基金资助:
    江西省教育厅科技项目(GJJ180393);核资源与环境国家重点实验室自主基金(Z1912);东华理工大学博士启动基金项目(DHBK2018030)

Pore Characteristics of Marine Shale in Lower Cambrian Hetang Formation in Xiuwu Basin

GUO Chunli1(), YANG Shuang1(), WANG Andong1, ZHANG Shuanglong2, QI Xing2   

  1. 1. East China University of Technology, a.State Key Laboratory of Nuclear Resources and Environment; b.College of Earth Science, Nanchang, Jiangxi 330013, China
    2. Geological Prospecting Institute of Jiangxi Coalfield Geology Bureau, Nanchang, Jiangxi 330001, China
  • Received:2020-06-01 Revised:2020-06-22 Online:2020-10-01 Published:2020-10-10
  • Contact: YANG Shuang E-mail:1418253657@qq.com;yangshuang18@ecut.edu.cn

摘要:

通过孔隙度实验、低温N2吸附法和CO2吸附法,对修武盆地RDZ01井下寒武统荷塘组页岩孔隙发育特征进行定量表征,结合总有机碳含量、矿物组成及有机质的热演化程度,讨论孔隙发育特征主控因素。结果表明:孔隙形态以楔形孔为主,并发育墨水瓶形孔及狭缝形孔。页岩孔隙度为1.24%~2.91%,具低孔隙度特征;微孔、中孔和大孔3类孔隙分别占总孔体积的35.45%、44.54%和20.01%。页岩总孔体积为5.33×10-3 ~20.10×10-3 cm3/g,其中低温N2吸附法和CO2吸附法平均孔体积分别为7.40×10-3 cm3/g和2.24×10-3 cm3/g;总比表面积为7.62~17.84 m2/g,其中低温N2吸附法和CO2吸附法平均比表面积分别为5.23 m2/g和7.41 m2/g。孔径分布的主峰值小于10.00 nm,微孔的结构复杂,0.30~0.70 nm的孔隙较为发育,大的比表面积为页岩气提供更多的吸附位。总有机碳含量是微孔发育的主控因素,同时促进中孔发育,对大孔的影响较弱;黏土矿物增多会降低页岩的孔隙度;高石英含量为总孔体积和总比表面积增大的有利因素。修武盆地下寒武统荷塘组海相页岩和鄂西地区下侏罗统自流井组页岩储集层特征相似,呈现良好的储集能力。

关键词: 修武盆地, 下寒武统, 荷塘组, 孔隙, CO2吸附法, 低温N2吸附法, 孔径, 海相页岩

Abstract:

Based on porosity and low temperature N2 and CO2 adsorption experiments, the pore characteristics of the shale in the Lower Cambrian Hetang formation were quantitatively characterized. And combined with TOC, whole rock X-ray diffraction and previous research on the thermal evolution of organic matter, the controlling factors on the pore characteristics were discussed and analyzed. The results show that most pores are wedge-shaped, and less are like bottle-neck and slits. The porosity of the shale ranges from 1.24% to 2.91%, of which mesopores, micropore and macropore account for 44.53%, 35.45% and 20.01%, respectively. The total pore volume of the shale ranges from 5.33× 10-3 cm3/g to 20.10×10-3 cm3/g, of which the average pore volumes of BJH and DFT are 7.40×10-3 cm3/g and 2.24×10-3 cm3/g, respectively. The total specific surface area is 7.62 to 17.84 m2/g, of which the average specific surface areas of low-temperature N2 adsorption and CO2 adsorption are 5.23 m2/g and 7.41 m2/g, respectively. The peak pore size is less than 10.00 nm, and the micropore structures are complex. The pores of 0.30-0.70 nm are relatively developed, but the larger specific surface area provides more room adsorbing shale gas. TOC is the controlling factor on micropore development, and it is helpful to the development of mesopores, but influences less on macropores. Clay minerals reduce the shale porosity, while quartz is a favorable factor on the total pore volume and total specific surface area. With the similar characteristics to the Lower Jurassic Ziliujing formation shale in the western Hubei province, the marine shale of the Lower Cambrian Hetang formation in Xiuwu basin has a good reservoir capability.

Key words: Xiuwu basin, Lower Cambrian, Hetang formation, pore, CO2 adsorption, low-temperature N2 adsorption, pore size, marine shale

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