摘要
近年来,孟加拉湾北部若开盆地新生界沉积地层内不断取得深水油气勘探发现.本研究基于高分辨率3D地震反射资料,在若开盆地上上新统沉积地层内识别出水道、天然堤、朵体(决口扇、含分支水道朵体)、半深海泥、块体搬运沉积体等多种深水沉积单元.结合钻井的测井、岩屑样品结果,进一步确认了水道、天然堤、朵体沉积单元,并针对过井沉积体开展沉积储层特征及勘探潜力的分析和对比研究,获取了储层级别及其平面分布范围.由于若开盆地上新世以来沉积地层整体埋藏较浅,压实作用较弱且成岩作用程度低,水道、天然堤和朵体均可能为若开盆地中新统-上新统生物气的主力勘探烃藏提供储集空间.其中,蜿蜒型紧密叠置浊积水道是尤其具有厚沉积、强连通、广展布、高砂地比和高孔隙系数的优质深水油气储集类型.研究成果可为深水油气勘探提供重要指导和启示.
Abstract
[Significance]In recent years,notable discoveries in deep-water oil and gas exploration have emerged in the Rakhine Basin,located in the northern Bay of Bengal.[Methods]In this study,high-resolution 3D seismic data from the Rakhine Basin were used to identify deep-water sedimentary architectural elements,including chan-nels,levees,lobate fans(such as crevasse-splay lobes and distributary channel-lobe complexes),hemipelagic mud,and mass-transport deposits.Alongside drilling logs and sampling results,the reservoir characteristics and exploration potential of channels,levees,and lobes in the wells were further analyzed,and the reservoir hierarchy and spatial distribution were determined.[Results]Notably,the Rakhine Basin is characterized by relatively shal-low burial depths,weak compaction,and minimal diagnostic alteration since the Pliocene,positioning channels,levees,and lobate fansas potential exploration targets for shallow biogenic gas.In particular,meandering stacked channels emerge as a high-quality reservoir type due to their thick sediment accumulation,strong connectivity,widespread distribution,and elevated high sand content and porosity.[Conclusion]The research findings can provide important guidance and insights for deep-water oil and gas exploration.
维普
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