紫金山热事件对鄂尔多斯盆地东缘B区块致密气成藏控制作用

通过对鄂尔多斯盆地东缘紫金山火成岩岩体空间分布刻画和演化过程分析，结合其周边B区块致密气成藏过程恢复，探讨了紫金山火山活动对致密气成藏的控制作用。研究认为：从空间分布来看，紫金山岩体地下最大分布范围是地表出露面积的17倍；紫金山火山主要活动时间处于区域成藏期内，火山活动促进了区域生烃作用，加速了火成岩周边13.5km范围内源岩的成熟和生烃作用；火山活动造成断裂和裂缝的发育，导致了天然气沿断裂快速向浅层垂向运移成藏，是远源成藏的主要原因；火山活动产生的大量裂缝改善了周边3~15km范围内储层的渗透性；火山活动带来的隆升和断裂作用破坏了紫金山顶部保存条件，造成了局部超压封盖的开启，破坏了先存致密气藏。通过对生烃、运移、储集、封盖和保存过程的影响，紫金山火山活动控制了周边致密气藏分布特征。

The domination of tight sand gas accumulation by the Zijinshan thermal event in the block B,eastern Ordos Basin

Through the spatial distribution and the evolution investigation of the Zijinshan volcano, in combination with the tight sand gas accumulation process analysis in block B, the study of the effect on tight sand gas accumulation by the evolution of Zijinshan volcano was carried on. Conclusions are drawn out: the maximum area of the underground Zijinshan igneous is 17 times as large as the surface; the main activity time of Zijinshan volcano is in the regional accumulation period; the activities of Zijinshan volcano promoted regional hydrocarbon generation and accelerated the maturation of source rocks within a range of 13.5km around igneous rocks；the development of faults and fractures caused by volcanic activities has led to the rapid vertical migration of natural gas from the fault to the shallow formation, forming gas accumulation in the upper play; a large number of fractures caused by volcanic activity improve the permeability of surrounding reservoirs within a range of 3-15km; the uplift and fracture caused by volcanic activities have damaged the hydrocarbon preservation of the Zijinshan area, caused the opening of overpressure cap, and destroyed the gas reservoir. Through the influence of hydrocarbon generation, migration, accumulation, cap and preservation processes, the distribution characteristics of the tight sand gas reservoirs are controlled by the activities of Zijinshan volcano in block B.