鄂尔多斯盆地致密砂岩气烃源岩特征分析

Analysis of Source Rock Characteristics of Tight Sandstone Gas in Ordos Basin

以往的勘探开发证实,煤层和暗色泥岩是鄂尔多斯盆地的主要烃源岩,通过50余口致密砂岩气井烃源岩厚度揭示的纵横向展布特征,发现煤层与暗色泥岩在纵向上具有对气源的互补特征,在横向上具有厚度重合度差。此外,烃源岩具有高TOC和R0平面分布差异大的特征。总体来看,鄂尔多斯盆地烃源岩厚度大、高TOC和高R0,但在勘探开发过程中,这些优势很难得以发挥。因此,认为查明烃源岩与控藏的关系,明确关键控藏因素指导高效的勘探开发,是当前的关键突破方向。

Previous exploration and development have proved that coal seams and dark mudstones are the main source rocks in the Ordos Basin.Based on the vertical and horizontal distribution characteristics revealed by the thickness of source rocks in over 50 tight sandstone gas wells,it is found that coal seam and dark mudstone are complementary to gas sources in the vertical direction,and have poor thickness overlap in the horizontal direction.In addition,the source rock has the characteristics of high TOC and significant differences in Ro plane distribution.On the whole,the source rocks in the Ordos Basin process a large thickness,high TOCand high Ro.However,during the process of exploration and development,it has proven challenging to fully utilize these advantages.Therefore,it is considered that the key breakthrough direction at present is to identify the relationship between source rocks and reservoir control and clarify the key controlling factors to guide efficient exploration and development.