西南石油大学学报(自然科学版)

Previous Articles     Next Articles

Shale Gas Accumulation Conditions of Lower Jurassic in Junggar Basin

GAO Jin*, CAO Zhe   

  1. College of Geosciences,China University of Petroleum(Beijing),Changping,Beijing 102249,China
  • Online:2016-02-01 Published:2016-02-01

Abstract:

Junggar basin is a large petroliferous basin in western China,in which there has deposited several hydrocarbon source
rocks. Jurassic,one of the most significant gas sources,is considered to contain a huge potential of shale gas resources. Based
on drilling data,logging data,outcrop data,core data and laboratory test results of rock samples,we analyzed the shale gas
accumulation conditions through the distribution of dark shale and burial depth,organic geochemical characteristics,reservoir
conditions and gas-bearing features of lower Jurassic and predicted favorable formation and zone for shale gas exploration. Shale
interval of lower Jurassic is widely distributed. In the northwestern margin and southern margin,the dark shale is thickest. The
burial depth of lower Jurassic shale tends to deepen from north to south with a range between 1 000 m to greater than 4 500 m.
The organic carbon content is relatively high,and the main type of organic matter is III and II2,which is gas-prone. The thermal
maturity of Lower Jurassic shale is from immature to high mature. The shale reservoir is characterized by low porosity,high
clay minerals content and micro fracture for storage. The measured absorbed gas content is averaging 1.42 m3/t,the gas logging
show of dark shale is active. In addition,the in situ gas desorption test identified the existence of nature gas in lower Jurassic
shale. As a result,Lower Jurassic Badaowan shale is the favorable Formation,Shawan Dabasong region is the favorable zone
for shale gas accumulation.

Key words: shale gas, accumulation conditions, lower Jurassic, favorable zone, Junggar Basin

CLC Number: