Analysis Of The Component And Enrichment Conditions Of Shale Gas In The Northern Of Guizhou

Shale gas is a new type of unconventional energy,it is highly valued by all countries in the world.The potential of shale gas accumulation in the world is huge,and it has become a new target for oil and gas exploration and exploitation in countries all over the world.China has abundant reserves of shale gas recoverable resources,and there are several organic-rich shales in the northern of Guizhou region,especially the Niutitang and Longmaxi Formations.The shale is widespread,with large thickness,high organic matter abundance,and thermal maturity.Good degree is the potential area for shale gas exploration and development.However,the exploration and mining of shale gas in China is still at a preliminary stage.The understanding of shale gas enrichment and reservoir conditions needs to be studied.The understanding of shale gas generation,accumulation,and preservation conditions in complex tectonic regions in Guizhou is unclear.The"desert zone"choice lacks a systematic evaluation index system.In this paper,on the premise of researching and summarizing a large number of domestic and foreign periodical documents and related data,the shale formations of the Niutitang and Longmaxi formations in the northern of Guizhou region will be the mainly analytical horizons,and the gas content of the core samples taken will be analyzed on site.The components were determined,and the isotope test was used to analyze the main causes of the factors;through a large number of indoor sample tests,the main controlling factors of shale gas enrichment conditions in in the northern of Guizhou region were comprehensively analyzed from the conditions for shale gas production,reservoir conditions,and preservation conditions.And use the idea of dimension reduction,factor analysis of the main control factors affecting shale gas accumulation factor analysis,the absolute weight of the comprehensive evaluation of the northern of Guizhou shale gas exploration area for favorable exploration area evaluation.The results of the study show that:?1?The study area is located at the north end of the central Guizhou uplift.The main features are early settlement,late uplift,long settling period,short uplift period and long-term development,and continuous evolution of marine-continental complex integration.On the other hand,the Niutitang and Longmaxi formations shale intervals have relatively high gas content,ranging from 2 to 4 m³/t.In the gas composition analysis,there is a low CH₄ content in the Niutitang formation.The phenomenon of N₂,while the Longmaxi formation is dominated by CH₄,ranging from 95.25%to 99.3%,containing only a small amount of hydrocarbon gases and trace amounts of CO₂ and N₂.?2?The content of organic carbon in the Niutitang and Longmaxi formations in the northern of Guizhou is generally larger,with a mean content of not less than 3.0%.The organic matter has a high maturity and is generally in a highly evolved stage.The organic components are mainly composed of I and II,the shale gas generation conditions are good.The shale gas in the two research layers is rich in brittle minerals such as quartz and calcite,and the average content is not less than 70%.It contains a small amount of clay minerals.The page of the Longmaxi Formation The rock formation is a mesoporous low-permeability reservoir that is conducive to inducing fracture systems.The caps of the relevant investigation wells of the Longmaxi formation are covered with Class I caps,and they have good capping ability as a whole.The fractures at multiple phases of activity are the key factors for the preservation of shale gas in the northern of Guizhou.?3?The seven main controlling factors?such as organic carbon content,organic matter maturity,etc.?that affect shale gas enrichment were analyzed by factor analysis and classified into three common factors,namely adsorption factor,hydrocarbon generation factor,and reservoir factor.Based on the evaluation results of the absolute weighted scores,the target areas for the shale gas exploration in the Northern of Guizhou are mainly in the preferred target area,and the optimal target area and general target area are relatively few.