新庄复杂小断块稠油油藏成藏规律分析

Hydrocarbon accumulation analysis of heavy oil reservoir in complex fault block of Xinzhuang oilfield

新庄油田构造破碎、含油宽度窄、面积小、原油粘度高、水油体积比大,系典型的复杂小断块稠油油藏。根据成藏要素及空间、成藏作用及时间等匹配关系研究,对该油田的成藏过程和成藏模式进行了分析,认为新庄储层砂体以扇状或指状从凹陷边缘伸入生、盖区,与生、盖层大面积接触,为油气运移、聚集创造了良好的条件;油气主要来自其南部深凹区的核三段烃源岩,在廖庄末期达到生排烃高峰;鼻状构造形成的圈闭不晚于油气的主要生成期;由于断层的活动,油气沿断层垂向运移,遇高孔渗砂层沿砂层继续侧向运移,断层形成遮挡在高部位油气聚集。

Xinzhuang oilfield is a typical complex small fault block reservoir and has the characteristics of a fractured structure, narrow oil- bearing width and small area,high viscosity of crude oil and big water - oil volume ratio.Based on matching relation among time,space and hydrocarbon accumulation, the process and pattern of hydrocarbon accumulation have been analyzed.The analysis shows that reservoir bodies entered oil source area and capping layers in fan or finger shaped feature from depression margin,with a large contact area to oil source area and capping layers,which provides a favorable condition for hydrocarbon accumulation and migration. The hydrocarbon was found to mainly come from He -Ⅲformation in the south of deep depression area and reached the generation and expulsion peak of hydrocarbon at late Liaozhuang period.The formation time of the trap caused by nose - like structure was no later than the main hydrocarbon generation period.Because of fault activity,hydrocarbon migrated vertically along the fault,continued to migrate laterally along the sandstone with high porosity and high permeability,if there was,and finally sealed hydrocarbon at a structural high position.