天然气工业2017，Vol.37Issue(6)：1-11,11.DOI:10.3787/j.issn.1000-0976.2017.06.001
四川盆地东南缘南华系大塘坡组烃源岩特征及其油气勘探意义
Characteristics of source rocks of the Datangpo Fm, Nanhua System, at the southeastern margin of Sichuan Basin and their significance to oil and gas exploration
摘要
Abstract
In recent years,much attention has been paid to the development environment,biogenetic compositions and hydrocarbon generation characteristics of ancient source rocks in the deep strata of the Sichuan Basin because oil and gas exploration extends continuously to the deep and ultra-deep strata and a giant gas field with the explored reserves of more than 1 tcm was discovered in the Middle and Upper Proterozoic-Lower Paleozoic strata in the stable inherited paleo-uplift of the central Sichuan Basin.Based on the previous geological research results,outcrop section of the Datangpo Fm,Nanhua System,at the southeastern margin of the Sichuan Basin was observed and the samples taken from the source rocks were tested and analyzed in terms of their organic geochemistry and organic petrology.It is shown that high-quality black shale source rocks of the Datangpo Fm are developed in the tensional background at the southeastern margin of the Sichuan Basin between two glacial ages,i.e.,Gucheng and Nantuo ages in the Nanhua Period.Their thickness is 16-180 m and mineral compositions are mainly clay minerals and clastic quartz.Besides,shale in the Datangpo Fm is of high-quality sapropel type source rock with high abundance at an over-mature stage,and it is characterized by low pristane/phytane ratios (0.32-0.83),low gammacerane abundance,high-abundance tricyclic terpane and higher-content C27 and C29 gonane,indicating that biogenetic compositions are mainly algae and microbes in a strong reducing environment with low salinity.It is concluded that the Datangpo Fm source rocks may be developed in the rift of Nanhua System in central Sichuan Basin.Paleo-uplifts and paleo-slopes before the Caledonian are the favorable locations for the accumulation of dispersed liquid hydrocarbons and paleo-reservoirs derived from the Datangpo Fm source rocks.In addition,scale accumulation zones of dispersed organic matter cracking gas and paleo-reservoirs originated from the Datangpo Fm source rocks may be discovered in the stable area inside the Sichuan Basin.关键词
四川盆地/南华纪/大塘坡组沉积期/烃源岩/地球化学特征/有机碳/裂解气/盐度Key words
Sichuan Basin/Nanhua System/Depositional stage of Datangpo Fm/Source rock/Geochemical characteristic/Organic carbon/Cracking gas/Salinity引用本文复制引用
谢增业,魏国齐,张健,杨威,张璐,王志宏,赵洁..四川盆地东南缘南华系大塘坡组烃源岩特征及其油气勘探意义[J].天然气工业,2017,37(6):1-11,11.基金项目
国家科技重大专项(编号:2016ZX05007-003)、中国石油天然气股份有限公司科技项目(编号:2016B-0602). （编号:2016ZX05007-003）
