松南新区彰武断陷油气地质特征及成藏条件分析

利用3 口钻井资料和新采集二维地震资料，对彰武盆地油气地质特征和成藏条件进行了综合分析。结果表明: 沙海组和九佛堂组具备良好的生储盖条件和配置关系，发育自生自储式、下生上储式和上生下储式3 套生储盖组合类型。良好的生储盖组合、断层侧向封挡、近源成藏是本区主要的成藏控制条件，构造--岩性油藏是主要的油藏类型。沙海组烃源岩有机质以ⅡB 型为主，Ro 值主要为 0. 5% ～ 0. 7%，处于低熟演化阶段; 九佛堂组烃源岩有机质以Ⅰ型和ⅡA 型为主，Ro 值主要为0. 7% ～ 1. 0%，处于成熟阶段。沙海组整体上属于中孔、低--中渗型储层，九佛堂组储层整体上属于低孔、特低渗储层。沙海组顶部泥岩构成区域盖层，九佛堂组顶部泥岩可作为直接盖层。九佛堂组邻近优质烃源岩、地层厚度大，成藏潜力更大，可以作为下一步勘探的优先目标。

Geological features and oil-gas accumulation conditions of Zhangwu depression in new exploration area of southern Songliao Basin

The half-faulted Zhangwu Basin is one of the typical low-degree exploration areas among the depressions in southern Songliao Basin． Three boreholes and new 2D seismic data are used to analyze petroleum geologic features and oil-gas accumulation conditions of the studied area． The results show that there are favorable source-reservoir-cap assemblages in Shahai and Jiufotang formations． such as‘self-generation with self-accumulation’，‘ lower-generation with upper-accumulation’and‘upper-generation with lower-accumulation’． Favorable source-reservoir-cap assemblages，lateral sealing by faults and near-source conditions are controlling factors of petroleum accumulations in this area，primarily forming structural-lithologic reservoirs．Organic matters of source rocks in Shahai Formation are mainly ⅡB type，and the Ro ranges between 0. 5% and 0. 7%，indicating a low maturity stage． Organic matters of source rocks in Jiufotang Formation are mainly Ⅰ and ⅡA in type and the Ro ranges between 0. 7% and 1. 0%，indicating a maturity stage． Reservoir rocks in Shahai Formation have middle porosity and low to middle permeability，while those in Jiufotang Formation have low porosity and very low permeability． Mudstone in the top of Shahai Formation is similar to regional cap rocks，and mudstone in the top of Jiufotang Formation provides direct sealing． As source rocks are with higher quality and reservoir rocks with higher proportion，there is greater potential for petroleum accumulations in Jiufotang Formation，which can be selected as target priority for the future exploration．