Relationship Differences and Causes between Porosity and Organic Carbon in Black Shales of the Lower Cambrian and the Lower Silurian in Yangtze Area
Xu Zhuang
Shi Wanzhong
Zhai Gangyi
Bao Shujing
Zhang Xiaoming
Wang Ren
Wang Jian
Wang Chao
Yuan Qi
Abstract：The black shales in lower Cambrian Niutitang and lower Silurian Longmaxi develop well in Yangtze area, which are the key horizons for shale gas exploration because of its wide distribution, large thickness, high organic matter abundance.The porosity of Niutitang Formation shows a distinct difference from Longmaxi Formation.There are also significant differences in the pore structure, organic carbon content and density of the two sets of shales.Based on the logging data, buried depth (overlying pressure), porosity, organic carbon and maturity test data, comparative analysis is conducted.Results show that pore structure has been affected by the high degree of thermal evolution and organic carbon of Niutitang Formation.Organic matter is carbonized, organic porosity is collapsed and filled.The depth of Niutitang Formation is deep and the overburden pressure is also large, causing the inorganic porosity to be compacted.These factors make the porosity of Niutitang Formation obviously less than Longmaxi Formation.
Keywords：shaleporosityorganic carbonmaturityLongmaxi FormationNiutitang Formationpetroleum geology.
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：12( 1223-1234 )