川东奉节及周缘地区下三叠统飞仙关组沉积特征及相带演化

根据野外剖面观察和室内镜下岩石薄片鉴定分析，结合最新钻井资料，以岩石学、古生物及地球物理解释成果为基础，确定研究区早三叠世飞仙关组早期的孤立碳酸盐台地模式和晚期的连陆碳酸盐台地模式，细分为局限台地、开阔台地、台地边缘浅滩、台地前缘斜坡和陆棚／盆地等沉积相类型。通过关键层序界面识别，将飞仙关组划分为2个三级层序和5个四级层序，建立了四级层序地层格架。层序格架内沉积相演化规律表明，飞仙关期，自早期到晚期水体逐渐变浅，发生充填补齐的沉积作用，奉节地区沉积格局逐渐由开阔台地-台地边缘-前缘斜坡-海槽相过渡为局限台地-开阔台地，至飞仙关晚期完全准平原化为局限台地潮坪沉积。

川东南—黔西北地区上二叠统龙潭组海陆过渡相页岩气富集条件及主控因素

利用有机岩石学、干酪根碳同位素、X-射线衍射、场发射扫描电镜等实验测试资料,阐述了川东南—黔西北地区上二叠统龙潭组海陆过渡相页岩烃源岩品质、储层发育及含气性特征,并探讨了孔隙类型和含气性的主控因素。研究表明,川东南—黔西北地区龙潭组泥页岩总有机质丰度高(TOC值平均为3.50%)、热演化程度高(R_(O)值平均为2.23%),有机显微组分以镜质体为主,惰质体次之,以Ⅲ型干酪根为主,是一套优质气源岩。页岩储层具有较好的物性(孔隙度平均为5.56%),孔隙类型以黏土矿物孔为主,其中伊/蒙混层间微孔隙较发育,主要为介孔—微孔,有机质孔基本不发育。泥页岩吸附气含量和总含气量变化较大。有机显微组分是控制龙潭组高成熟富有机质页岩有机孔隙发育的首要因素,有机质丰度是控制页岩吸附能力和含气性的重要因素。

Dispositional characteristics of Ordovician Wufeng Formation and Silurian Longmaxi Formation in Sichuan Basin and its adjacent areas

According to data of gas wells and typical sections of Wufeng Formation and Longmaxi Formation in Sichuan Basin,shale of various graptolite zones were analyzed to determine depositional environment,lithology and thickness characteristics of the graptolite shale interval of WF2-WF3 in the lower part of Wufeng Formation,the graptolite shale interval of WF4 in Guanyinqiao Member of Wufeng Formation and the graptolite shale interval of LM1-LM4 in the bottom of Longmaxi Formation,and characteristics of shale horizontal distribution were also investigated.During the depositional period of the graptolite shale interval of WF2-WF3,the study area was less affected by the Guangxi movement,the depositional environment was the deep water of open sea,where black shale was mainly deposited;the sedimentation center was developed in northeast Guizhou-northeast Sichuan and south Sichuan,the maximum thickness was from 4 to 6 m in the sedimentation center.During the depositional period of the graptolite shale interval of WF4,the depositional environment in the study area changed greatly due to global sea level fall and enhanced Guangxi movement;the central Sichuan paleouplift,the central Guizhou paleouplift and the Jiangnan-Xuefeng palaeouplift were further expanded,and the area of the sedimentary basin decreased;the depositional environment was mainly carbonate bioclastic shoal of shallow sea,and partially deep sea which only was distributed in the Shizhu-Fuling-Wuxi area in east and northeast Sichuan and the Gongxian-Yongchuan area in south Sichuan;sediments of shallow water were dominated by limestone and argillaceous limestone with abundant Hirnantia,sediments of deep water were dominated by calcareous mudstone and shale with Hirnantia.During the depositional period of the graptolite shale interval of LM1-LM4,due to rise of global sea level and Guangxi movement,the sedimentary area was larger than that in the depositional period of Guanyinqiao Member,and the sedimentary environment mainly was stagnant deepwater;thickness of black shale in the graptolite shale interval of LM1-LM4 was large,and the maximum thickness was over 20 m.Furthermore,control of the central Sichuan paleouplift,the central Guizhou paleouplift and the Jiangnan-Xuefeng paleouplift on black shale was discussed,and control of the Zhiliujing underwater highland/uplift,Huayingshan highland and Dingshan highland as well as western Hubei-Hunan underwater highland/uplift on shale deposition and preservation was also investigated.

Pore characteristics and formation mechanism of high-maturity organic-rich shale in Lower Cambrian Jiumenchong Formation,southern Guizhou

In order to investigate pore characteristics and formation mechanism in the high-maturity organic-rich shale of Lower Cambrian Jiumenchong Formation in southern Guizhou,the pore structure,pore type and storage properties are well studied through the rock thin section,total rock X-ray diffraction,lowtemperature nitrogen adsorption,high pressure mercury injection-adsorption test,helium porosity test,argon ion polishing-scanning electron microscope,thermal evolution and pore evolution history reconstruction,and based on the diagenesis and compaction as well as thermal evolution process,a microscopic pore formation and evolution model of high-maturity organic-rich shale are established.The result shows that the high-maturity organic-rich shale of Jiumenchong Formation has the average total specific surface area of 12.66m^(2)/g and the total pore volume of 11.54×10^(-3)cm^(3)/g,and the total specific surface area have a positive correlation with total pore volume;the total specific surface area and the total pore volume are slightly lower compared with the Lower Silurian shale.The pores are dominated by micropores and mesopores,while macropores are very rare.The pores of the organic-rich shale mainly are organic pores with small diameter usually less than 30 nm,and the pore boundary form is irregular,the inorganic mineral pores are not developed.Compared with the Silurian shale,the shale has poorer reservoir property,the average porosity is only 2.80%;the horizontal permeability is 1e3 times of the vertical permeability,indicating the horizontal lamellations are not developed.The formation and evolution of pores in high-maturity organic-rich shale is jointly influenced by the evolutionary process of intergranular pores of inorganic mineral under the control of the diagenesis and compaction,the organic pore formation process in the hydrocarbon generation-oil formation-oil and gas transformation sequence under the control of thermal evolution,and the natural gas loss-supply equilibration process under the condition of later pore preservation.