阳信洼陷火成岩对烃源岩形成及演化的作用

Effect of igneous rocks on formation and evolution of source rocks in Yangxin Sag

阳信洼陷沙河街组主力烃源岩中发育有玄武岩和辉长岩等基性火成岩,并伴有规模不等的热液活动。火成岩热液为烃源岩提供了大量矿物质和养料,使火成岩上部地层的烃源岩中有机质富集,形成优质烃源岩。火成岩及其热液活动给烃源岩带来热量、大量过渡金属矿物和外部氢源,这些因素使烃源岩在进入成熟门限之前即可生成低熟油气。同时,降低火成岩区生油门限的深度,可使烃源岩存在多个生烃高峰。建立了阳信洼陷火成岩区烃源岩的演化模式。

The basahs and gabbros were developed in the main hydrocarbon source rocks of Yangxin Sag. and thermal waters were distributed more or Iess. The magmas and thermal-waters provided a large quantity of volcanic minerals and nutriments for the souree rocks,which resulted in the shale around igneous rocks with abundam organic carbon. The shale was basieally excellent source rock with high potential hydrocarbon. The magmas and thermal waters brought tire transitional metals and heat to source rocks, which caused mature organic matter of tbe source rocks and hydrocarbon generation earlier. The transitional metals and some volcanic rain erals were active catalysts to hydrocarbon generation from the organic matter in the source rocks around tire igneous rocks, which represented immature oil and gas being generated at low temperatures or shallow format ion in the burial of the source rocks and igneous rocks. The evolution model of source rocks in Yangxin Sag was established.