渤海海域黄河口凹陷近源晚期优势成藏模式

Late-stage near-source preponderant hydrocarbon pooling pattern in the Huanghekou Sag of the Bohai Sea waters

彭文绪 孙和风 张如才 余宏忠 张新涛

Peng Wenxu Sun Hefeng Zhang Rucai Yu Hongzhong Zhang Xintao

黄河口凹陷是渤海南部海域一个富生烃凹陷,已经发现的油气藏具有中-浅埋深(1200～1800m)、原油密度中等、产能高(新近系最高455.3m/d)等特点.油气成藏以近源垂向运移为主,主要成藏时间为5.1Ma以来,主力油层明显受层序控制,油层主要分布于最大湖泛面以下,成藏模式可以归纳为"近源晚期优势".5年来(2004—2008年),该凹陷勘探地质成功率为85%,平均单井发现三级石油地质储量713×10m,至2008年已经钻探近100口探井.在20世纪80—90年代初发现渤中25-1/S、渤中34-2/4、渤中28-1和渤中26-2等油田的基础上,近几年相继发现了渤中34-1、渤中28-2S、渤中29-4、渤中26-3等中、浅层中型油气田,形成了渤海南部海域油气发现的新高潮.

Being a hydrocarbon kitchen,the Huanghekou sag in the south of Bohai Sea waters had seen many oil and gas discoveries featuring in shallow to middle burial depth (1200-1800 m),moderate crude API,high productivity(as high as 455.3 m3/d of gas from the Neogene),etc.Most of its oil and gas reservoirs were formed through near-source vertical migration and the pooling process has started since 5.1 Ma.Its major reservoirs are apparently controlled by stratigraphic sequences and most of the reservoirs are located below the maximum flooding surface.The pooling pattern can be generalized into "near-source,late-stage,and preponderance".During the period of 2004 to 2008,success rate of exploration in the sag was up to 85%,and 3P geological reserves of single exploratory well averaged at 7.13 MMCM.By the end of 2008,about 100 exploration wells had been drilled.In addition to the discoveries obtained during the 1980s to early 1990s,such as Bozhong 25-1/S,Bozhong 34-2/4,Bozhong 28-1 and Bozhong 26-2,several medium-sized discoveries including Bozhong 34-1,Bozhong 28-2S,Bozhong 29-4 and Bozhong 26-3 have been found in layers with shallow to middle burial depth,initiating a new surge of oil and gas discoveries in the south part of Bohai Sea waters.

10.11743/ogg20090419