松辽盆地北部昌德地区含CO2气藏特征及成藏模式

松辽盆地北部深层由于地层埋藏深度大,地质结构复杂、地温高、成岩作用强,岩性岩相变化大,因而导致深层天然气聚集规律复杂,勘探难度大。松辽盆地在对烃类天然气长期勘探并取得巨大突破的同时,也意外地发现了一些高含CO2气藏。CO2气藏直接影响并制约烃类气藏勘探部署,因此研究CO2气藏特征及成藏模式对突破天然气勘探瓶颈具有重要意义。本文通过对昌德地区CO2气藏特征的分析,建立出含CO2气藏成藏模式。昌德地区CO2气藏的形成是地球深部地质作用形成富含CO2气热液的资源库、以渗流与间歇性涌流的方式向上运—聚的产物。由强烈的壳-幔相互作用使深部资源进入地壳的软流圈上涌区、地壳中的＂拖网＂结构以及深大断裂的各类高角度断层和由深大断裂引发的一系列的岩浆活动沟通了深部流体与盆地的联系,运移到盆地中有效构造部位,并提供了良好的储盖条件后聚集成藏。

Gas Reservoir Characteristics and Pool-forming Model of CO2 in Changde Raea of the Northern Songliao Basin

In the north of Songliao bisin,because formation buried depth,geological structure complicated,underground temperature high,diagenesis strong,lithology and lithofacies changed,thus these result in complex of deep natural gas accumulation rule and more difficulty of exploration.For hydrocarbon natural gas of Songliao bisin,long-term exploration and made great breakthrough,at the same time we also found some high containing CO2 gas reservoir.CO2 gas reservoir directly affects and restricts the hydrocarbon reservoir exploration and deployment,so the study of CO2 gas reservoir characteristics and pool-forming model has important significance for breakthrough the bottleneck of natural gas exploration.Through analyzing CO2 gas reservoir characteristics of Changde area,this article set up pool-forming model of containing CO2 gas reservoir.CO2 gas reservoir formation in Changde area is that geological effect form rich-containing CO2 gas hydrothermal resource pool in deep earth,are product upward migration and accumulation by seepage and intermittent flow way.The strong crust-mantle interaction make deep resources into the earth’s crust asthenosphere upwelling area,the earth’s crust ＂net＂ structure,all kinds of high angle fault in deep-large fracture and by the deep-large fracture caused a series of magmation communicate the contact of deep fluid and basin,migrate to the basin effective tectonic position,and provide a good reservoir-cap condition for accumulation and pool-forming.