珠江口盆地白云凹陷烃源岩品质分析及其沉积期古氧相研究
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摘要
本文通过有机质的丰度、类型及成熟度三个方面对珠江口盆地白云凹陷烃源岩进行初步评价,并创新性设定指数"Z",来综合表征有机质丰度。研究认为白云凹陷的烃源岩主要为较好—好的烃源岩。统计分析了Z值在平面上的总体变化规律,可得洼陷地区的烃源岩优于凸起地区。并利用放射性测井钍铀比值(Th/U)分析烃源岩沉积的古氧相环境,可得凸起地区的烃源岩氧化性沉积环境明显;而洼陷地区还原性沉积环境明显。自下而上来看,珠海组烃源岩古氧相的还原性较珠江组更强;文昌组较恩平组更强。通过对比分析指数Z及古氧相发现:古氧相还原性越强的地区,其Z值越大。具体表现为古氧相的还原性越强,烃源岩有机质丰度越高,烃源岩的品质越高。
This paper evaluates the source rocks of the Baiyun depression in the Pearl River Mouth Basin via three aspects:abundance,type and maturity of organic matters,and sets an innovative index"Z"to comprehensively represent the abundance of organic matters.It is concluded that the source rocks in Baiyun depression are mainly good-good source rocks.The general variation law of Z value in the plane is statistically analyzed,and the source rock of the sag is superior to the raised area.Also,the ratio of thorium to uranium(Th/U)is used to analyze the ancient sedimentary environment of source rocks.The ancient sedimentary environment of source rocks in raised area is mainly oxidation,and that in sag is reducibility.From the bottom up,the reducibility of the paleo-oxygen phase of the hydrocarbon source rocks in Zhuhai is stronger than that in the Pearl River formation;the Wenchang formation is stronger than the Enping formation.By comparing the index Z and the paleo-oxygen phase,the Z value is larger in the region with the strong reducibility of the paleo-oxygen phase.The specific representation is that the higher reducibility of the organic matter,the higher the organic matter abundance of the source rock and the higher the quality of the source rock.
This paper evaluates the source rocks of the Baiyun depression in the Pearl River Mouth Basin via three aspects:abundance,type and maturity of organic matters,and sets an innovative index"Z"to comprehensively represent the abundance of organic matters.It is concluded that the source rocks in Baiyun depression are mainly good-good source rocks.The general variation law of Z value in the plane is statistically analyzed,and the source rock of the sag is superior to the raised area.Also,the ratio of thorium to uranium(Th/U)is used to analyze the ancient sedimentary environment of source rocks.The ancient sedimentary environment of source rocks in raised area is mainly oxidation,and that in sag is reducibility.From the bottom up,the reducibility of the paleo-oxygen phase of the hydrocarbon source rocks in Zhuhai is stronger than that in the Pearl River formation;the Wenchang formation is stronger than the Enping formation.By comparing the index Z and the paleo-oxygen phase,the Z value is larger in the region with the strong reducibility of the paleo-oxygen phase.The specific representation is that the higher reducibility of the organic matter,the higher the organic matter abundance of the source rock and the higher the quality of the source rock.
引文
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[2]米立军,张功成,傅宁,等.珠江口盆地白云凹陷北坡-番禺低隆起油气来源及成藏分析[J].中国海上油气,2006,18(3):161-168.
[3]朱俊章,施和生,庞雄,等.珠江口盆地番禺低隆起天然气成因和分析[J].天然气地球科学,2005,16(4):456-459.
[4]郭小文,何生.珠江口盆地番禺低隆起轻质原油地球化学特征及其对比研究[J].地质科技情报,2006,25(5):63-68.
[5]朱伟林,张功成,高乐,等.南海北部大陆边缘盆地油气地质特征与勘探方向[J].石油学报,2008,29(1):1-9.
[6]朱伟林,米立军,高乐,等.2007年中国近海油气勘探回顾[J].中国海上油气,2007,20(1):1-8.
[7]张红静,张敏,张春明,等.珠江口盆地白云凹陷珠江组、珠海组烃源岩倾油倾气性判识[J].地质科技情报,2010,29(2):5-9.
[8]胡见义,徐树宝,窦立荣,等.烃类气成因类型及其富气区的分布模式[J].天然气地球科学,1991(1):1-5.
[9]黄第藩.在华北地台下奥陶统地层中发现低成熟的碳酸盐岩烃源岩[J].石油勘探与开发,1991,19(4):323-332.
[10]秦建中,钱志浩,曹寅,等.油气地球化学新技术新方法[J].石油实验地质,2005,29(5):519-528.
[11]贺轲.利用Th/U比值曲线研究沉积环境古水深变化[J].中国石油和化工标准与质量,2012,33(9):230-231.
[12]郑大中.铀的迁移富集机理新探索[J].四川地质学报,2003,23(2):77-87.
[13]黄隆基,首祥云,王端平.自然伽马能谱测井原理及应用[M].北京:石油工业出版社,1995:48-55,179-183,193-194.
[14]代大经,唐正松,陈鑫堂,等.铀的地球化学特征及其测井响应在油气勘探中的应用[J].天然气工业,1995,15(5):21-27.