摘要
渤海湾盆地是典型的油型盆地,天然气地质储量占比较小,气源岩主要为中—深湖相的Ⅱ2—Ⅱ1型干酪根,晚期构造活跃导致天然气保存条件较差,油型湖盆大型天然气田形成条件研究一直是业界难题。基于渤海湾盆地勘探实践成果,结合国内外大型气田类比剖析,从成藏动力、构造和沉积3个方面开展大型天然气藏形成条件研究,提出渤海湾盆地常规大型天然气藏形成的条件主要包括一个核心要素和两个关键要素。一个核心要素即古近系区域超压泥岩'被子'强封盖,两个关键要素包括烃源岩晚期快速熟化高强度生气和大规模储集体。在此基础上,建立了渤海湾盆地大型天然气成藏与富集贫化模式,进一步划分为区域超压泥岩发育富集型、局部超压泥岩发育贫化型、富砂沉积洼陷贫化型和晚期断裂强发育贫化型4种常规大型天然气富集贫化模式,指出环渤中凹陷、辽中凹陷北部、板桥凹陷等地区具备大型天然气富集的有利条件、值得勘探探索,对渤海湾盆地大型天然气藏勘探具有重要的借鉴意义。
The Bohai Bay Basin is a typical oil-prone basin,in which natural gas geological reserves have a small proportion.In this basin,the gas source rock is largely medium-deep lake mudstone with oil-prone type II2-II1 kerogens,and natural gas preservation conditions are poor due to active late tectonic movements.The formation conditions of large natural gas fields in the Bohai Bay Basin have been elusive.Based on the exploration results of Bohai Bay Basin and comparison with large gas fields in China and abroad,the formation conditions of conventional large-scale natural gas reservoirs in the Bohai Bay Basin were examined from accumulation dynamics,structure and sedimentation.The results show that the formation conditions of conventional large natural gas reservoirs in Bohai Bay Basin mainly include one core element and two key elements.The core factor is the strong sealing of Paleogene'quilt-like'overpressure mudstone.The two key factors include the rapid maturation and high-intensity gas generation of source rock in the late stage and large scale reservoir.On this basis,large-scale nature gas accumulation models in the Bohai Bay Basin have been worked out,including regional overpressure mudstone enriching model,local overpressure mudstone depleting model,sand-rich sedimentary subsag depleting model and late strongly-developed fault depleting model.It is found that Bozhong sag,northern Liaozhong sag and Banqiao sag have favorable conditions for the formation of large-scale natural gas reservoirs,and are worth exploring.The study results have important guidance for exploration of large scale natural gas reservoirs in the Bohai Bay Basin.
作者
薛永安
王德英
XUE Yong'an;WANG Deying(CNOOC China Limited Tianjin Branch,Tianjin 300459,China)
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2020年第2期260-271,共12页
Petroleum Exploration and Development
基金
“十三五”国家科技重大专项课题“渤海海域勘探新领域及关键技术研究”(2016ZX05024-003)。
关键词
渤海湾盆地
油型湖盆
大型天然气藏
渤中19-6
区域超压泥岩“被子”
晚期快速高强度生气
大规模储集体
Bohai Bay Basin
oil type lacustrine basin
large nature gas pool
Bozhong 19-6
regional'quilt-like'overpressure mudstone
rapid and high-intensity gas generation in late period
large scale reservoir
