The Formationof The Trough And Its Effect Of The Organic-rich Shale Of Dalong Formation,during Late Permian Epoch,in Northeast Part Of Chongqing

This thesis takes the shales from Upper Permian Series of Dalong Formation as the main subject to study.According to the field geological observation and the regional tectonic background analysis,this thesis discusses the geotectonic evolution and its shales gas implications of Upper Permian Series of Dalong F ormation,Northeast of Chongqing Province.With the organic geochemistry anal yze and test,for the rock sample from the studying area specially.We can dra w the conclusion below:1?The deposition of Dalong Formation is strictly limited by geotectonic,i t only located in Chengkou-E'xi trough and Kaijiang-Liangping trough,there is no appearance of Dalong Formation in any other places.2?At late permian epoch,The distortion of ancient tectonicframework in r esearch area is “two uplift and two depression”.The palaeogeomorphology is “three edge and two height”.With the expansion of South QinLing Sea,the dev elopment of Emei Taphrogeny,the activity of basement rift,Chengkou-E'xi tro ugh and Kaijiang-Liangping trough were shaped.3?The performance of the controlling(The Formation of the trough control the Dalong Formation)embed in 3 aspects: The combined action of three tecto nic movement formed the trough,which controlled the deposition environment of Dalong Formation.The sedimentation environment effect the growth,distribu tion and the organic substance of organic-rich shale from Dalong Formation.4?Based on the the criteria for subdivision and correlation,such as the ro ck color,structure and texture.The sedimentary facies of Dalong Formation are from basin facies to deep-water shelf facies.The shales of Dalong Formation are mainly deposited in the deep-water shelf face.5?The mineral components of Dalong shales are mainly clay and brittle mineral.Quartz is the dominated part of brittle mineral.Ledikite,illite-montmor illonite mixed-layer and chlorite are the major in the clay.6?The kerogen type of organic matterfrom Upper Permian Series Of Dalo ng Formation is predominantly?type.The majority of Maceral is sapropelic(60%~80%).The evolution of source rock is during mature and post-mature stage,th e value of Ro changed from 2.0%~3.0%.the value of TOC is also high,it wa s mainly located in the section 2~4% and >6%.