渤海海域渤中19-6大型凝析气田形成条件与成藏特征  

Formation conditions and accumulation characteristics of Bozhong 19-6 large condensate gas field in offshore Bohai Bay Basin

作　　者：徐长贵 于海波 王军 刘晓健 XU Changgui;YU Haibo;WANG Jun;LIU Xiaojian(CNOOC China Limited,Tianjin Branch,Tianjin 300459,China)

机构地区：[1]中海石油(中国)有限公司天津分公司,天津300459

出　　处：《石油勘探与开发》2019年第1期25-38,共14页Petroleum Exploration and Development

基　　金：国家科技重大专项"渤海海域勘探新领域及关键技术研究"(2016ZX05024-003-001)

摘　　要：深入分析渤中凹陷天然气资源基础、低潜山圈闭形成机制、优质储集层控制因素和天然气保存条件,总结渤中19-6大型凝析气田的形成条件与成藏特征。研究表明,渤中凹陷多套巨厚的腐殖-腐泥型烃源岩在高演化阶段大量生气是大型气田形成的物质基础,印支期以来多期次构造演化形成了大规模的深埋低潜山圈闭,郯庐断裂活动形成了多类型储集层,潜山太古界变质岩和古近系孔店组砂砾岩是本区优质储集层。巨厚的超压湖相泥岩与较弱的新构造运动配置形成了良好的保存条件。渤中19-6气田属于大型特高含凝析油凝析气藏,天然气成因类型为腐殖-腐泥气和干酪根降解气,具有气层厚度大、气柱高度大、成藏过程先油后气的特征,潜山为块状气藏,孔店组砂砾岩为层状气藏,气藏具有超压源岩多途径强充注、多套常压—弱超压储集层汇聚、厚层超压泥岩盖层保存、天然气超晚期快速成藏的成藏模式。Based on the study of natural gas resource,low buried hill trap formation mechanism,high quality reservoir control factors and natural gas preservation conditions,the formation conditions and reservoir accumulation characteristics of Bozhong 19-6 large condensate gas field were summarized.Large gas generation potential of multiple sets of thick humic-sapropelic source rocks in high maturity stage in Bozhong depression was the basis of large gas field formation.The multi-stage tectonic evolution since Indosinian period formed large-scale buried hill traps.The Tanlu fault activity formed multi-type reservoirs,and buried hill metamorphic rock of Archean and sand-conglomerate of Kongdian Formation were high-quality reservoirs.Thick overpressure lacustrine mudstone and weak neotectonic movement provided good preservation conditions.Bozhong 19-6 gas reservoir was a condensate gas reservoir with very high condensate oil content,and the gas origin was humic-sapropelic and kerogen-cracking gas,and the gas field had large gas thickness,high gas column characteristics and the accumulation process was first oil and then gas.The buried hill reservoir was a massive reservoir and the Kongdian reservoir was a stratified reservoir.The gas field had multi-channel hydrocarbon intense charge from overpressure source rocks,atmospheric-weak overpressure reservoir favorable for accumulation,thick overpressure mudstone caprock favorable for preservation,and natural gas ultra-late rapid accumulation model.

关 键 词：渤海海域 渤中19-6气田 凝析气 低潜山 变质岩储集层 成藏特征 太古界 

分 类 号：TE122[石油与天然气工程—油气勘探]