Abstract: As oil and gas exploration enters a highly mature stage, the discovery rate of traditional large-scale structural traps and lithologic composite reservoirs has significantly decreased. Exploration targets are shifting towards small-to-medium-sized subtle reservoirs, posing challenges in tapping into remaining hydrocarbon resources in highly mature exploration areas. To address this demand, a research was conducted on the structural ridge transport model and hydrocarbon accumulation characteristics. Based on three-dimensional seismic data from typical blocks in Songliao Basin, the spatial distribution of structural ridges was characterized using maximum curvature attributes. Combined with hydrocarbon accumulation conditions, the relay-type transport pattern from source to fault to sink to accumulation for structural ridges was analyzed. Further, a method for predicting remaining oil was developed based on structural ridge migration pathway analysis. The research results show as follows. (1) Structural ridges can be classified into three basic types: nose-shaped ridge, faulted-anticlinal ridge, and fault-block ridge. (2) The structural ridge transport systems can be categorized into three types: fault-structural ridge system, fold-structural ridge system and composite structural ridge system. (3) Hydrocarbon reservoirs associated with structural ridges can be divided into two categories: stable and unstable. Stable reservoirs develop in traditional traps with anticline-sandbody configurations, exhibiting a unified oil-water contact. In contrast, unstable reservoirs are controlled by the coupling effect between structural ridges and sandbodies in slope areas, characterized with tilted oil-water contacts and low oil saturation. This method breaks through traditional trap-based exploration ideas. It has successfully identified multiple subtle hydrocarbon enrichment zones in the highly mature exploration areas of Songliao Basin (Block T191 and Jiangqiao area), increasing over 10 million tons of proven reserves. This breakthrough provides new geological theories and technical supports for fine exploitation and development in mature exploration areas.

Key words: hydrocarbon migration model, structural ridge transport system, nose-shaped ridge, faulted-anticlinal ridge, fault-block ridge, non-steady reservoir, Songliao Basin

摘要： 随着油气勘探进入高成熟阶段,传统大型构造油气藏和岩性复合油气藏的发现率显著降低,勘探目标向中—小型隐蔽油气藏转移,高成熟探区面临着剩余油气资源挖潜的难题。针对这一需求,开展构造脊输导模式与油气聚集特征研究,基于松辽盆地典型区块的三维地震资料,利用最大曲率属性刻画的构造脊空间展布特征,结合油气成藏条件,分析了"源-断-汇-聚"接力式构造脊输导模式,在此基础上进一步构建了基于构造脊运移路径分析的剩余油预测方法。研究结果表明:①构造脊可划分为鼻状脊、断背脊和断块脊3种基本类型;②构造脊输导体系可划分为断层构造脊输导型、褶皱构造脊输导型和复式构造脊输导型3类;③构造脊相关油气藏可划分为稳态油气藏和非稳态油气藏2类,其中,稳态油气藏发育于背斜-砂体配置的传统圈闭内,具有统一油水界面,而非稳态油气藏受控于斜坡区的构造脊-砂体耦合作用,表现为倾斜油水界面和低饱和度的特征。该方法突破传统圈闭勘探的思路,在松辽盆地高成熟探区(T191区块和江桥地区)成功识别出多个隐蔽油气富集区,新增探明储量超千万吨,为成熟探区的精细勘探开发提供了新的地质理论与技术支撑。

关键词: 油气输导模式, 构造脊输导体系, 鼻状脊, 断背脊, 断块脊, 非稳态油藏, 松辽盆地