东营断陷盆地地层流体超压系统与油气运聚成藏

Effect of formation superpressure system on hydrocarbon migration and accumulation in Dongying Fault Basin

东营断陷盆地古近系发育的地层流体超压系统对油气运聚、成藏至关重要。以实测数据和用测井资料预测的地层流体压力数据为依据 ,分析了区内的地层流体压力系统特征 ,并将其分为上部常压、中部超压、下部常压 3个压力系统。超压系统具有纵向分带、平面分区且复杂多变的特点 ,但在宏观上属于盆地级的“超压流体封存系统”。超压系统对油气运聚成藏的作用主要是提供油源、产生运移动力和通道 ,并决定油气充注成藏方式。研究结果表明 ,与盆内超压系统有关的油气成藏模式分为系统内、系统外和封隔层 3种形式 ;超压系统内部的相对低压区及其上、下或侧向的泄压区都是油气聚集的有利地区。

The formation superpressure system developed in the Palaeogene system of Dongying Fault Basin plays an important role in hydrocarbon migration and accumulation. On the basis of formation pressure data obtained from real measurement and logging, the pressure system was classified into three types, namely normal pressure systems in upper and lower sections, superpressure system in medium section. The superpressure system was characterized by vertical zonality, lateral subregion and complex variation. It still belongs to basin-order superpressure fluid compartment. The superpressure system can provide oil sources, migration forces and channels for hydrocarbon migration and accumulation, and it can also determine oil and gas charge and reservoir accumulation mode. The hydrocarbon accumulation mode related to superpressure system can be divided into three types. It is reported that the relative underpressure region within superpressure system and pressure-released region around were the potential areas for hydrocarbon accumulation.