摘要
油气勘探证实东海X凹陷中央背斜带深层低渗-特低渗砂岩储层蕴含丰富的天然气资源,而针对低渗-特低渗储层油气资源的地质认识尚不深入,极大地制约了东海油气增储上产。Y构造是X凹陷最大反转背斜构造,通过对烃源岩特征、储层物性和成岩作用等的深入分析研究,并结合其热史-埋藏史,重点阐明了气藏主力产层花港组砂岩的低渗-特低渗演化过程、低渗-特低渗化影响因素与储层成岩-成藏耦合关系。研究表明,Y构造在龙井运动反转期剥蚀量超过1200 m,说明花港组砂岩储层13 Ma曾经历历史最大埋深与最高温度,易形成低渗-特低渗砂岩储层。根据研究区砂岩储层致密化程度及演化特征,可以将气藏划分为花港组H3砂层组成藏未特低渗气藏、H4—H5边成藏边特低渗气藏和H8—H12先特低渗后成藏之气藏。在此基础上,结合油气成藏过程分析,建立了中央背斜带“花港组垂向两期充注、龙井组调整运移”成藏模式。
Oil and gas exploration has confirmed that the deep low to ultra-low permeability sandstone reservoirs in the central anticline of the X Sag in the East China Sea contain abundant natural gas resources.However,the geological understanding of oil and gas resources in low-permeability to ultra-low permeability reservoirs is not yet deep,which greatly restricted the increases of oil and gas reserves and production in the East China Sea.The Y Structure is the largest inversion anticline structure in the X Sag.Through in-depth analysis on the characteristics of source rocks,reservoir properties,and diagenesis,combined with its thermal burial history,we elucidated the evolution process of low to ultra-low permeability sandstones in the main production layer of the gas reservoir,and clarified the impact factors on the low to ultra-low permeability and the coupling relationship between reservoir diagenesis and reservoir formation.Results show that during the reversal period of the Longjing Movement,the amount of the thickness eroded from the Huagang Formation in the Y Structure exceeded 1200 m,indicating that the sandstone reservoir of the Huagang Formation experienced the maximum burial depth in history and the highest temperature in 13 Ma,making it easy to form low to ultra-low permeability sandstone reservoirs.According to the degree of densification and evolutionary characteristics of sandstone reservoirs in the research area,three sets of the gas reservoirs were recognized:the H3 sand layer of the Huagang Formation composed of lowpermeability gas reservoirs,the H4-H5 reservoir formed while forming ultra-low permeability gas reservoirs,and the H8-H12 reservoir formed first and then ultra-low permeability gas reservoirs.On this basis,combined with the analysis of the process of oil and gas reservoir formation,a reservoir formation model of“two-stage vertical filling in Huagang Formation and adjustment-migration in Longjing Formation”was established in the central anticline belt.
作者
李宁
于仲坤
刁慧
王皖丽
丁飞
余箐
LI Ning;YU Zhongkun;DIAO Hui;WANG Wanli;DING Fei;YU Qing(Shanghai Branch of CNOOC(China)Ltd.,Shanghai 200335,China)
出处
《海洋地质前沿》
北大核心
2025年第5期22-31,共10页
Marine Geology Frontiers
基金
“十四五”全国油气资源评价项目“中海油矿业权区及周边空白区油气资源评价”(QGYQZYPJ2022-3)
中海石油(中国)有限公司重大科技专项“东海西湖凹陷大中型气田勘探方向及关键技术研究”(KJZX-2023-0101)。
关键词
东海陆架盆地
X凹陷
深层
低渗-特低渗
形成条件
成藏模式
East China Sea Shelf Basin
X Sag
deep layer
low and ultra-low permeability
formation conditions
accumulation model
