国外海相油气田勘探实例之二西班牙卡萨布兰卡裂缝性喀斯特油田

西班牙东部海域的卡萨布兰卡油田发现于1975年1980年晚期投入生产。介绍了该油田的勘探史,描述了该盆地的构造演化史,区域地层、沉积相及储层特征等。该油田主要由以北东、南西向断层为界的具有五个相互独立高点的台地相碳酸盐岩潜山圈闭构成上覆中新统页岩盖层其主力油层为中上侏罗统和下白垩统石灰岩和白云岩烃源岩主要含型干酪根总有机碳为石灰岩主要由球粒骨架粒泥灰岩和泥粒灰岩泥岩和少量骨架颗粒灰岩构成这些灰岩均因致密胶结而基本损失原始孔隙而绝大多数的白云岩为细晶白云岩原生孔隙微乎其微基质孔隙度仅为5%

Cases of Discovery and Exploration of Marine Fields in the World (Part 2):Casablanca Fractured Karstic Carbonate Oil Field, Spanish

The Casablanca Field situated in the Gulf of Valencia offshore eastern Spain.The field was discovered in 1975 andput into production in late 1980.The exploration history, basin evolution, regional stratigraphy and depositional facies of the fieldis introduced in detail.The trap is a series of buried hills on an eroded fault block with five culminations containing Jurassic andLower Cretaceous karstified platform carbonate reservoirs beneath a Miocence shale seal.Oil to source rock correlation in the gulfof Valencia show that the main source rocks are the low energy, dysaerobic, fine-grained, commonly laminated, marlstones andlimestones. These source rocks predominantly contain Type II kerogens and have TOC of 3.2%￣4.7%. The Mesozoic limestonesconsist largely of peloidal-skeletal wackstones and packstones, mudstones and minor skeletal grainstones that are all tightlycemented with negligible original porosity.Most of the dolomites are finely crystalline,also with very little original porosity.Ingeneral, matrix porosities are poor (5%).