渤中凹陷西南环特大型高产油气聚集带的发现与勘探启示

Discovery and exploration implications of super-large high-yield oil and gas accumulation zone in the southwest belt of Bozhong sag

渤中凹陷西南环历经20多年的油气勘探,早期以构造(或断块)圈闭为目标的勘探方式在凹陷带勘探逐渐步入困境;近10年,针对深层潜山提出“陆相断陷盆地天然气成藏理论技术”,针对浅层新近系提出“汇聚脊控藏理论技术”,指导发现了一系列大中型深层潜山天然气田、深层潜山油气田及浅层油田,这些油气田横向连片、纵向叠置,形成了渤中凹陷西南环特大型高产油气聚集带,提交国家探明油气地质储量超8亿吨油当量。深层潜山油气藏主要包括渤中19-6凝析气藏、渤中13-2油气藏、渤中26-6油气藏等,这些油气藏普遍具有埋深大、油品性质好、储量规模大、测试产能高的特征,形成高产气藏、凝析气藏和高挥发油藏;浅层岩性油藏以渤中19-2新近系油藏为典型代表,具有纵向油层少、单砂体面积大、测试产能高的特征。渤中凹陷西南环特大型高产油气聚集带的成功发现也为渤海湾盆地后续勘探带来重要启示:深层潜山和浅层疏松砂岩岩性圈闭将是渤海海域今后最主要的油气勘探类型;存在“湖盆成气”“汇聚脊”控藏地质条件的凹陷带是渤海湾盆地下一步油气勘探的有利方向。

After more than 20 years of oil&gas exploration in the southwest belt of Bozhong sag,the early exploration method with structural(or fault block)trap as the target has gradually entered a dilemma in the depression belt.In the past 10 years,we have proposed the“natural gas accumulation theory and technology in continental rift basin”for deep buried hills and“catchment ridge reservoir controlling theory and technology”for shallow Neogene system,and guided the discovery of a series of large-medium sized deep buried hill gas fields,deep buried hill oil-gas fields and shallow oil fields,which are transversely connected and longitudinally superimposed,forming a super-large high-yield oil and gas accumulation zone around the southwest belt of Bozhong sag,and a proved oil-gas reserves of more than 800 million tons of oil equivalent has been reported.Deep buried hill oil-gas reservoirs mainly include BZ19-6 condensate gas reservoir,BZ13-2 reservoir,BZ26-6 reservoir,etc.,which are generally characterized by large burial depth,good oil properties,large reserves and high test productivity,forming high-yield gas reservoirs,condensate gas reservoirs and high volatile oil reservoirs.The shallow lithologic reservoir is typically represented by BZ19-2 Neogene reservoir,which is characterized by few longitudinal reservoirs,large single sand body area and high test productivity.The successful discovery of the super-large high-yield oil and gas accumulation zone in the southwest belt of Bozhong sag also brings important implications for the subsequent exploration in Bohai bay basin:deep buried hill and shallow loose sandstone lithologic trap will be the most dominant types of oil and gas exploration in Bohai sea in the future;the depression belt with the geological conditions of“gas generation in lake basin”and“catchment ridge”reservoir controlling is the favorable direction for further oil and gas exploration in Bohai bay basin.