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Title: Origin and accumulation of carbon dioxide in the Huanghua depression, Bohai Bay Basin, China
Author (s): Zhang, Tongwei
Zhang, Mingjie
Bai, Baojun
Wang, Xianbin
Li, Liwu
Department/Lab Affiliations: Energy Research and Development Center
Geological Sciences & Engineering
Keywords: depression
gas geochemistry
mantle degassing
natural gas
postmagmatic stage
sedimentary basin
tectonic regions
thermal decomposition
Issue Date: 2008-03
Publisher: American Association of Petroleum Geologists (AAPG)
Citation: Zhang, Tongwei, Zhang, Mingjie., Bai, Baojun., Wang, Xianmin., and Li, Liwu. "Origin and accumulation of carbon dioxide in the Huanghua depression, Bohai Bay Basin, China." American Association of Petroleum Geologists Bulletin, vol. 92, no. 3, 2008.
Abstract: The CO2 content in natural gas in the Huanghua depression, Bohai Bay Basin, China, is highly variable, ranging from 0.003 to 99.6%. Understanding the origin and distribution of the CO2 is important to assess risk prior to drilling. This study uses gas geochemistry to identify the origins of CO2 in the sedimentary basin and places these findings within a geologic context. Chemical compositions, d13CCO2 , 3He/4He, and 40Ar/36Ar were measured for 50 gas samples collected from gas- and oil-producing wells located in different tectonic regions in the depression. From these analyses, we determined that the CO2 in the Huanghua depression originated from three sources: thermal decomposition of organic matter, thermal decomposition of carbonate minerals, and mantle degassing. Gases with low amounts (<3%) of CO2 tend to be organogenic. This organogenic CO2 occurs in hydrocarbon accumulations and is characterized by d13CCO2 values ranging from –20 to –10{per thousand} and low 3He/4He (R/Ra < 1, herein R and Ra represent the 3He/4He ratio of sample and air, respectively). Carbon dioxide originating from thermal carbonate decomposition occurs as a minor component (<10%) in hydrocarbon gas accumulations and is characterized by a narrow range of d13CCO2 (–2 to +2{per thousand}) and R/Ra < 1. Huanghua depression natural gases with CO2 content in excess of 15% resulted from mantle degassing and mainly occur at the intersection of faults. These gases have 3He/4He ratios in excess of atmospheric value (R/Ra > 1) and d13CCO2 ranging from –5 to –3{per thousand}. Volatiles from mantle degassing during the postmagmatic stage are the most likely major source for CO2 in these high-CO2-content reservoirs. Basement faults likely provide pathways for the upward migration of CO2-rich mantle fluids. Consequently, CO2-rich gas pools are locally concentrated in the Gangxi and Dazhongwang fault zones within the depression.
Type: Article - Journal
text
In Title: American Association of Petroleum Geologists Bulletin
Copyright Notice: This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.
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Publisher URL:
http://dx.doi.org/10.1306/10230706141
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titleOrigin and accumulation of carbon dioxide in the Huanghua depression, Bohai Bay Basin, China
contributor.authorZhang, Tongwei
contributor.authorZhang, Mingjie
contributor.authorBai, Baojun
contributor.authorWang, Xianbin
contributor.authorLi, Liwu
contributor.deptlabEnergy Research and Development Center
contributor.deptlabGeological Sciences & Engineering
contributor.sponsorNational Natural Science Foundation of China
subjectdepression
subjectgas geochemistry
subjectmantle degassing
subjectnatural gas
subjectpostmagmatic stage
subjectsedimentary basin
subjecttectonic regions
subjectthermal decomposition
date.issued2008-03
publisherAmerican Association of Petroleum Geologists (AAPG)
identifier.citationZhang, Tongwei, Zhang, Mingjie., Bai, Baojun., Wang, Xianmin., and Li, Liwu. "Origin and accumulation of carbon dioxide in the Huanghua depression, Bohai Bay Basin, China." American Association of Petroleum Geologists Bulletin, vol. 92, no. 3, 2008.
identifier.pub.URI
http://dx.doi.org/10.1306/10230706141
description.abstractThe CO2 content in natural gas in the Huanghua depression, Bohai Bay Basin, China, is highly variable, ranging from 0.003 to 99.6%. Understanding the origin and distribution of the CO2 is important to assess risk prior to drilling. This study uses gas geochemistry to identify the origins of CO2 in the sedimentary basin and places these findings within a geologic context. Chemical compositions, d13CCO2 , 3He/4He, and 40Ar/36Ar were measured for 50 gas samples collected from gas- and oil-producing wells located in different tectonic regions in the depression. From these analyses, we determined that the CO2 in the Huanghua depression originated from three sources: thermal decomposition of organic matter, thermal decomposition of carbonate minerals, and mantle degassing. Gases with low amounts (<3%) of CO2 tend to be organogenic. This organogenic CO2 occurs in hydrocarbon accumulations and is characterized by d13CCO2 values ranging from –20 to –10{per thousand} and low 3He/4He (R/Ra < 1, herein R and Ra represent the 3He/4He ratio of sample and air, respectively). Carbon dioxide originating from thermal carbonate decomposition occurs as a minor component (<10%) in hydrocarbon gas accumulations and is characterized by a narrow range of d13CCO2 (–2 to +2{per thousand}) and R/Ra < 1. Huanghua depression natural gases with CO2 content in excess of 15% resulted from mantle degassing and mainly occur at the intersection of faults. These gases have 3He/4He ratios in excess of atmospheric value (R/Ra > 1) and d13CCO2 ranging from –5 to –3{per thousand}. Volatiles from mantle degassing during the postmagmatic stage are the most likely major source for CO2 in these high-CO2-content reservoirs. Basement faults likely provide pathways for the upward migration of CO2-rich mantle fluids. Consequently, CO2-rich gas pools are locally concentrated in the Gangxi and Dazhongwang fault zones within the depression.
typeArticle - Journal
type.DCMITypetext
rightsThis material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.
rightsUnknown Policy
rights.URI
http://www.aapg.org/contacts/index.cfm
relation.isPartOfAmerican Association of Petroleum Geologists Bulletin
date.available2008-07-28T16:20:21Z
identifier.persist.URI
http://scholarsmine.mst.edu/post_prints/CO2OriginsandItsAccumulationintheHuanghuaDepr_09007dcc80536a61.html