高邮凹陷北斜坡韦码地区阜宁组油气富集差异分析

Petroleum accumulation diversity of Funing Formation in Weima area,northern slope belt of Gaoyou Sag

韦码地区是高邮凹陷北斜坡西部阜宁组富油气区块,剩余资源潜力较大,但是油气运移主路径不明,油气富集成藏差异控因不清。针对问题,利用大量的录井油气显示数据、油藏参数及原油地化指标和区域供烃情况等资料,在生储盖、构造特征、输导体系和油藏特征分析基础上,根据区内有成熟、低熟和特低熟3类原油现象,依据油—岩成熟度对应原则,指出存在东南部马家嘴成熟油源、中部浅槽与车逻鞍槽混合的低熟油源、北部不同成熟度混合的特低熟油源,成为北斜坡同岩异熟烃灶供源的独特景观。运用油气显示特征、示踪油气运移的咔唑和噻吩地化参数,结合砂体、断层输导体系分析,指出了油气运移的主要网络、输导方向和供烃半径;明确了油气富集和流体分布特点,阐述了层状砂岩统一油水系统与梳状多油水系统叠置的新型油藏成因;提出同岩异熟烃灶是韦码地区油气富集呈片状差异的物质基础,断层输导体系是控制韦码地区油气运聚差异和带状富集的重要因素,并指出了下步滚动挖潜油气的2个方向。

The Weima area is one of the richest oil fields in the northern slope of the Gaoyou Sag,and has a large amount of residual oil resources. Some problems,such as petroleum migration pathways and the factors controlling accumulation,are not solved yet. Based on the data of the oil shows in well logs,reservoir parameters and crude oil geochemical index,we analyzed the characteristics of source rocks,reservoirs,cap rocks,tectonics,carrier systems and oil and gas pools. Three types of crude oils（ mature,low maturity and extra-low maturity） were found in the study area. According to the correlation of maturity between oil and source rock,it was pointed out that hydrocarbon in the study area was generated from the same source rock with different maturity levels in the north slope： mature oil source in the southeast of Majiazui area,mixed oil source with low maturity from the middle shallow sag and Cheluo saddle,and extra-low maturity oil source mixed with different maturity levels in the north. The geochemical parameters such as carbazole and thiophene,together with oil show features,were applied to study petroleum migration pathways,accumulation direction and hydrocarbon supply radius. The characteristics of hydrocarbon enrichment and fluid distribution were determined. The cause for a new reservoir type composed of both uniform and comb-like oil-water systems was described. The same source rock with different maturity levels was the material basis for the variation of oil enrichment in Weima area. Fault carrier systems were the main controlling factor for the direction and diversity of petroleum accumulation. In the end,two prospective areas were identified for potential petroleum resources.