{"title":"Application of Light Hydrocarbons in Natural Gas Geochemistry of Gas Fields in China","authors":"Shipeng Huang, Jianzhong Li, Tongshan Wang, Q. Jiang, Hua Jiang, X. Tao, Bin Bai, Ziqi Feng","doi":"10.1146/annurev-earth-070921-054917","DOIUrl":null,"url":null,"abstract":"Light hydrocarbons (LHs) are an important component of natural gas whose chemical and isotopic compositions play a vital role in identifying gas genetic type, thermal maturity, gas–gas correlation, gas–source correlation, migration direction and phase, and secondary alterations (such as evaporative fractionation, biodegradation, and thermochemical sulfate reduction) experienced by the gas pool. Through review of geochemical research into LHs over recent decades, and analysis of chemical and isotopic compositions of LHs of gases and condensates from more than 40 gas fields in China, we present an overview of the genetic mechanisms of LHs and the impacts of various factors on their geochemical compositions. The primary objectives of this review are to demonstrate the application of LH chemical and isotopic composition characteristics to gas geochemistry research and to assess the applicability and reliability of geochemical identification diagrams and parameters for determining gas genetic types, maturity, source, secondary alteration, and migration direction and phase. ▪ Three main genetic mechanisms are proposed for the formation of light hydrocarbons: thermal decomposition, catalytic decomposition of organic matter, and microbial action. ▪ Chemical and isotopic compositions of light hydrocarbons with different carbon numbers and/or structures can be used to identify the genetic types and maturity of natural gas. ▪ Content ratios and carbon isotopes of characteristic light hydrocarbons are good indicators for gas–gas and gas–source correlations. ▪ Secondary alterations (evaporative fractionation, biodegradation, thermochemical sulfate reduction) and migration of gas can be indicated by chemical and isotopic compositions of light hydrocarbons. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"68 1","pages":""},"PeriodicalIF":11.3000,"publicationDate":"2021-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"11","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Annual Review of Earth and Planetary Sciences","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1146/annurev-earth-070921-054917","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 11
Abstract
Light hydrocarbons (LHs) are an important component of natural gas whose chemical and isotopic compositions play a vital role in identifying gas genetic type, thermal maturity, gas–gas correlation, gas–source correlation, migration direction and phase, and secondary alterations (such as evaporative fractionation, biodegradation, and thermochemical sulfate reduction) experienced by the gas pool. Through review of geochemical research into LHs over recent decades, and analysis of chemical and isotopic compositions of LHs of gases and condensates from more than 40 gas fields in China, we present an overview of the genetic mechanisms of LHs and the impacts of various factors on their geochemical compositions. The primary objectives of this review are to demonstrate the application of LH chemical and isotopic composition characteristics to gas geochemistry research and to assess the applicability and reliability of geochemical identification diagrams and parameters for determining gas genetic types, maturity, source, secondary alteration, and migration direction and phase. ▪ Three main genetic mechanisms are proposed for the formation of light hydrocarbons: thermal decomposition, catalytic decomposition of organic matter, and microbial action. ▪ Chemical and isotopic compositions of light hydrocarbons with different carbon numbers and/or structures can be used to identify the genetic types and maturity of natural gas. ▪ Content ratios and carbon isotopes of characteristic light hydrocarbons are good indicators for gas–gas and gas–source correlations. ▪ Secondary alterations (evaporative fractionation, biodegradation, thermochemical sulfate reduction) and migration of gas can be indicated by chemical and isotopic compositions of light hydrocarbons. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
期刊介绍:
Since its establishment in 1973, the Annual Review of Earth and Planetary Sciences has been dedicated to providing comprehensive coverage of advancements in the field. This esteemed publication examines various aspects of earth and planetary sciences, encompassing climate, environment, geological hazards, planet formation, and the evolution of life. To ensure wider accessibility, the latest volume of the journal has transitioned from a gated model to open access through the Subscribe to Open program by Annual Reviews. Consequently, all articles published in this volume are now available under the Creative Commons Attribution (CC BY) license.