鄂尔多斯盆地西南缘镇泾地区中生界油藏具有致密低渗透、丰度低、储量大的特点,已钻遇的多口高产井显示出中生界具有良好的油气勘探潜力,已成为中石化能源接替区之一。通过烃源岩、储层物性、圈闭特征、成岩作用及泥岩欠压实特征分析,认为构造作用造成了成岩作用路径及过剩压力发生变化,进而使储层类型多样,最终导致了中生界成藏机理具有明显差异。将中生界延长组一延安组油藏成藏动力学机制划分为3种类型:自源高压封闭成藏动力学系统、自源“低压”半封闭成藏动力学系统和远源常压开放成藏动力学系统。自源高压封闭油薇勘探重点为高效储层;自源“低压”半封闭油藏勘探重点为碎屑岩古风化壳;而远源常压开放油藏勘探重点则为与古地貌有关的差异压实背斜。
The Mesozoic reservoirs of the Zhenjing area on the southwestern edge of the Ordos Basin feature in large tightness, low permeability, low abundance and large reserves. They possess huge exploration potentials which have been evidenced by several high-yield wells penetrating these reservoirs. The Zhenjing area now has become one of the main areas for reserve replacement of SINOPEC. Through the analysis of source rocks, physi- cal properties of reservoirs, trap features, diagenesis and characteristics of mudstone compaction, it is believed that tectonism resulted in the changes of diagenetic paths and overpressure distribution, and hereby the variaty of reservoir types. As a result, the Mesozoic hydrocarbon accumulation mechanism varies distinctively in diffe- rent layers. In this paper, dynamic mechanisms of hydrocarbon accumulation in the Yanhn and Yanchang for- mations are classified into three types, namely the indigeneous high-pressure enclosed type, the indegeneous low-pressure semi-enclosed type, and the distal nornlal-pressure open type. For the indigeneous high-pressure enclosed type, exploration should be focused on searching for highly-efficient reservoirs, while for the indege- neous low-pressure semi-enclosed type, clastic paleo-weathering crust should be the focus of exploration. As for the distal normal-pressure open type, the major exploration targets are differential compaction anticlines associ- ated with paleogeomorphology.