冀中坳陷长洋淀地区“古储古堵”潜山成藏模式

“新生古储”潜山成藏模式对以华北油田为代表的一大批古潜山油气田的勘探起到了重要作用。但是，随着勘探程度的提高，此类油藏已无新的发现。利用钻井、测井、化验分析和高品质三维地震资料，对长洋淀潜山内幕地层反射结构、储盖组合及分布特征的研究发现：该区潜山内幕地层自上而下为下古生界寒武系、新元古界青白口系和中元古界蓟县系，发育了寒武系府君山组为储层、馒头组为盖层和中元古界蓟县系雾迷山组为储层、新元古界青白口系为盖层的两套储盖组合。储层主要为白云岩，裂缝发育，具有较好的储集物性，而且新元古界青白口系可以形成对中元古界蓟县系雾迷山组的有效封堵，油源来自于下第三系，以断层和不整合面为主要供油通道，形成了“古储古堵”新类型潜山成藏模式。根据这一模式钻探了长3井，获得了高产油流。

Buried-hill reservoir-forming mode of "old reservoir-old sealing formation" in Changyangdian area of Jizhong Depression

The buried hill reservoir forming mode of “new source rock old reservoir” provided the exploration direction for a great number of buried hill oil and gas fields such as Huabei Oilfield. With the increase of exploration degree, this kind of reservoir has been run out. The strata reflection texture, precisely reservoir cap assemblages and distribution of buried hill stratigraphy in Changyangdian area were studied by using available information of drilling, logging, laboratory test and high quality 3D seismic data. The buried hill stratigraphy includes the Lower Paleozoic Cambrian system, the New Proterozoic Qingbaikou system and the Middle Proterozoic Jixian system from top to bottom. Two reservoir cap rock assemblages (the Cambrian Fujunshan Formation as reservoir and Mantou Formation as cap rock, and Wumishan Formation of the Middle Proterozoic Jixian system as reservoir and the New Proterozoic Qingbaikou system as cap rock) were developed. The reservoirs with predominated dolomites have good physical properties and developed fractures. Qingbaikou Formation of the New Proterozoic could be acted as the effective sealing formation for Wumishan Formation of the Middle Proterozoic. The hydrocarbon was derived from the Palaeogene, and the migration paths of hydrocarbon mainly included fault and unconformity surface. The buried hill reservoir forming mode of “old reservoir old sealing formation” consequently generated. This mode was used to drill Chang3 Well where the high yield oil production was obtained.