机构地区:[1]中国石油勘探开发研究院
出 处:《海相油气地质》2022年第1期84-92,共9页Marine Origin Petroleum Geology
基 金:中国石油“十四五”前瞻性基础性重大科技项目“海外重点领域油气勘探关键技术研究”(编号:2021DJ3105)资助。
摘 要:基于区域沉积环境及古地貌分析,充分利用岩心、薄片、测井和地震等资料,对秘鲁58区块二叠系Copacabana组的沉积相识别标志、沉积相类型及展布特征开展研究,建立了研究区碳酸盐岩的沉积模式,揭示出沉积储层发育的主控因素。研究表明:①Copacabana组属于碳酸盐台地沉积,可划分为开阔台地、局限台地和蒸发台地3种沉积相和开阔台地浅滩、滩间海,局限台地潟湖、浅滩和蒸发台地潮坪5种亚相。②Copacabana组下段广泛发育开阔台地颗粒滩;中段开阔台地滩间海由西南部延伸至工区大范围;上段由西南向东北依次发育开阔台地滩间海—开阔台地颗粒滩—局限台地潟湖沉积,上段顶部发育区域性风化壳。自下而上展示出退积—加积—进积的沉积序列。③储层发育受控于古地貌和海平面升降的双重作用:古地貌的高低造成风化程度的不同,进而控制了风化壳、砂屑白云岩、白云质灰岩储层的发育;海平面周期性变化引起颗粒滩的迁移,进而控制了颗粒灰岩储层的发育。明确了研究区风化程度有限,主要发育开阔台地颗粒滩,颗粒灰岩为研究区主要的储层类型。The deep Permian Copacabana carbonate formation is an important exploration interval in the Madre de Dios Basin in South America.The good gas test results and the discovering of commercial gas in Block 58 of Peru and its surrounding areas,reveal good prospects for exploration.Due to the complex depositional environment of carbonate rocks and the unclear distribution of reservoirs,the exploration of this formation is restricted.Based on the analysis of regional sedimentary environment and paleogeomorphology,combined with core description,thin section identification,well logging and seismic data analysis,the sedimentary characteristics and main controlling factors of Copacabana Formation were studied.It is shown that:(1)Copacabana Formation belongs to carbonate platform deposits,which can be divided into three sedimentary facies:open platform,limited platform and evaporation platform,and five subfacies:granular shoal,inter-shoal sea,lagoon,sandy debris shoal and tidal flat.(2)The granular shoal of open platform is widely developed in the lower part of the formation;the inter-shoal sea in the middle part of the formation extend from the southwest to the large area of the work area;the open platform inter-shoal-open platform granular shoal-restricted platform lagoon are developed from southwest to northeast in the upper part of the formation,and the regional weathering crust is developed at the top.The sedimentary sequence of retrogradation-aggradation-progradation is displayed from bottom to top.(3)Reservoir development is controlled by the dual effects of paleogeomorphology and sea level rising and falling:the height of paleogeomorphology leads to different weathering degrees,which further controls the development of weathered crust,sandy dolomite and dolomitic limestone reservoirs;the periodic change of sea level causes the migration of granular shoal,which then controls the development of granular limestone reservoirs.According to the above understandings,it is clear that the weathering degree is limited,the open
关 键 词:碳酸盐岩 沉积相 颗粒灰岩 主控因素 二叠系 玛德莱德迪奥斯盆地 秘鲁
分 类 号:TE122.2[石油与天然气工程—油气勘探]
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