T53 Unconventional Energy Resources

Sunday, 4 November 2018
1:30 PM - 5:30 PM
Room 145

THE CAUSES OF HIGH-CONTENT NITROGEN IN SHALE GAS: A CASE STUDY OF THE LOWER CAMBRIAN OF THE XIUWU BASIN, CHINA

Paper number: T53-14
Program: Technical Sessions
Time: 4:45 PM – 5:00 PM

Authors

  • Yizhou Huang Presenting Author
    China University of Petroleum (Beijing), Beijing
  • Tianlin Liu
    China University of Petroleum (Beijing), Beijing
  • Zhenxue Jiang
    China University of Petroleum (Beijing), Beijing
  • Yan Song
    China University of Petroleum (Beijing), Beijing
  • Yan Song
    Research Institute of Petroleum Exploration and Development, Beijing
  • Kun Zhang
    University of Utah, Salt Lake City, UT
  • Kun Zhang
    China University of Petroleum (Beijing), Beijing
  • Kun Zhang
    Research Institute of Petroleum Exploration and Development, Beijing
  • Shu Jiang
    University of Utah, Salt Lake City, UT
  • Chengzao Jia
    Research Institute of Petroleum Exploration and Development, Beijing
  • Weiwei Liu
    Jiangxi Provincial Natural Gas Company, Ltd., Nanchang
  • Ming Wen
    China University of Petroleum (Beijing), Beijing
  • Xuelian Xie
    Guangzhou Marine Geological survey, Guangzhou

Abstract

There are successes and failures in the exploration of marine shale gas in South China. In some shale gas blocks with good basis of hydrocarbon generating materials, the phenomena exists that the wells drilled are lack in gas but with high nitrogen content. As nitrogen is an indicator that directly reflects the preservation conditions of oil and gas, the study of nitrogen in shale will help to find out the regulations of the preservation and enrichment of hydrocarbon gases.

This study focuses on the Lower Cambrian shale in Xiuwu Basin, Yangzi area, with emphasis on the detailed study of the Jiangye-1 well, using gas component analyses, nitrogen isotope analyses, permeability tests in parallel and perpendicular direction and FIB-HIM experiments, also combining with seismic interpretation, core description, outcrops observation and other methods to study the generation of high nitrogen and low hydrocarbon in the Lower Cambrian shale, Xiuwu Basin.

The result shows that the nitrogen in the Lower Cambrian shale of the Xiuwu Basin is derived from the atmosphere and the deep crust-upper mantle. The shale stratification plane and the detachment layer in the bottom of the Lower Cambrian are the lateral passage for shale gas migrating to syncline limbs, and the widely developed deep faults are the vertical passage for shale gas diffusing into atmosphere. The nitrogen in the atmosphere also enters the shale reservoir in the same way along the stratification plane, the Lower Cambrian detachment layer and the deep faults. In the Jurassic, on the one hand, the volcanism on the basin margin increased the value of the paleo heat flow, promoted the graphitization of organic matter in shale and the collapse of organic pore, accelerating the loss of shale gas. On the other hand, it brought nitrogen from the deep crust and upper mantle of the crust. This study summarized diffusion pattern of shale gas, revealing the genesis of high nitrogen and low hydrocarbon in the plate-active region.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-320168

© Copyright 2018 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.