琼东南盆地崖城13-1气田油气地球化学特征及来源新认识  

New Understanding of Oil and Gas Geochemical Characteristics and Origin of Yacheng 13-1 Gas Field in Qiongdongnan Basin

作　　者：汪紫菱 何小胡 邓孝亮 梁刚 郭潇潇 WANG Zi-ling;HE Xiao-hu;DENG Xiao-liang;LIANG Gang;GUO Xiao-xiao(Research Institution,Hainan Branch of CNOOC Ltd.,Haikou 570100,China)

机构地区：[1]中海石油(中国)有限公司海南分公司研究院,海南海口570100

出　　处：《天然气地球科学》2024年第6期1061-1069,共9页Natural Gas Geoscience

基　　金：中海油“十四五”重大科技项目“海上深层/超深层油气勘探技术”(编号:KJGG2022-0404)资助。

摘　　要：近期,在琼东南盆地崖城13-1气田首次钻探了潜山领域自营井,并获得了商业性发现,使得该气田焕发出新的生机。为进一步挖潜崖城13-1构造区的勘探价值,需要明确其油气的来源,以供落实该区的资源潜力。利用新老钻井样品的分析化验资料,从油气的地球化学特征入手,精细分析了崖城13-1气田油气的成因类型和分布规律,明确了油气的来源。结果表明:崖城13-1气田天然气均为煤型气,南、北2块的天然气和凝析油特征存在明显差异。天然气干燥系数“北干南湿”,烃类气碳同位素组成“北重南轻”,成熟度“北高南低”;北块凝析油密度、黏度、凝点及含蜡量均比南块高,北块凝析油中芳烃含量及姥植比也明显比南块高。这种差异主要与油气的母质构成及成熟度有关,北块生烃母质中陆源输入更多,南块低等水生生物贡献增多。进一步油源对比发现,崖城13-1气田北块油气具有“双源”特征,既有来自北块本地崖城组煤系烃源岩的贡献,又有来自临近莺歌海凹陷渐新统烃源岩的贡献;南块油气则主要来自崖南凹陷崖城组陆源海相偏腐泥型的源岩贡献。Recently,the first self-operated well in the buried hill field was drilled around Yacheng 13-1 gas field,and the commercial discovery made the gas field glow with new vitality.In order to further explore the exploration value of Yacheng 13-1 structure,it is necessary to clarify its source of oil and gas for realizing the resource potential of the area.Based on the analysis and test data of new and old drilling samples,starting from the geochemical characteristics of oil and gas,this paper carefully analyzes the genetic types and distribution rules of oil and gas in Yacheng 13-1 gas field,and defines the source of oil and gas.The analysis shows that the natural gas in Yacheng 13-1 gas field is coal type gas,and the natural gas and condensate in the south and north blocks are obviously different.The drying coefficient of natural gas is"dry in the north and wet in the south",the carbon isotope of hydrocarbon gas is"heavy in the north and light in the south",and the maturity is"high in the north and low in the south".The density,viscosity,freezing point and wax content of the condensate in the north block are higher than those in the south block,and the aromatics content and planting ratio of the condensate in the north block are also significantly higher than those in the south block.This difference is mainly related to the composition and maturity of oil and gas parent materials.In the north block,the input of terrigenous hydrocarbon source materials is more,and the contribution of lower aquatic organisms in the south block is increased.Further oil source correlation shows that the oil and gas in the north block of Yacheng 13-1 gas field has the characteristics of"double source",with contributions from both the local coal measures source rocks of Yacheng Formation in the north block and the Oligocene source rocks of Yinggehai sag;The oil and gas in the south block mainly comes from the terrigenous marine sapropelic source rocks of the Yacheng Formation in the Yanan Depression.

关 键 词：天然气 凝析油 地球化学特征 成因类型 油源对比 

分 类 号：TE122.113[石油与天然气工程—油气勘探]