内蒙古杭锦旗探区石炭—二叠系天然气成藏模式

鄂尔多斯盆地北部杭锦旗探区泊尔江海子—三眼井断裂带南北两侧石炭—二叠系的烃源岩、储集层、源储关系、气水分布、油气运移及产能等成藏条件与特征都具有明显的区别。通过分析断裂带南、北天然气甲烷含量和密度特征的差异，认为断裂带以北天然气部分来自于南部。划分了3种不整合面运移通道类型，并通过分析断层特征，明确了南部生成的天然气可以通过不整合面和断层运移至断裂带以北。结合生储盖组合、运移输导等特征，确定了断裂带以南的伊陕斜坡区煤系气源岩与河流相致密砂岩储层的成藏组合特点为源储紧邻、广覆式分布，断裂带以北的继承性隆起区，虽本地气源条件较差，但与断裂带以南的源岩区构成侧接式组合。探区位于鄂尔多斯盆地北部石炭—二叠系准连续—非连续成藏过渡带上，依此建立了“源储紧邻、物性控藏”和“双源供气、圈闭控藏”南北两种不同的天然气成藏模式。

The Permo-Carboniferous Gas Reservoir Forming Model of Hangjinqi Exploration Area in Northern Ordos Basin,Inner Mongolia

In the north and south sides of Borjianghaizi Sanyanjing fault zone of Hangjinqi exploration area in northern Ordos Basin, the accumulation conditions and features of the Permo Carboniferous such as source rock, reservoir, the relationship between source rock and reservoir, gas and water distribution, deliverability etc have significant differences. By analyzing the differences of methane content and density of the natural gas in the south and north of the fault zone, the results show that some part of the natural gas which exists in the north of the fault zone was originated from the south. Three types of unconformity transport channel were divided. Through analyzing the characteristics of the faults, it is clear that the natural gas generated from the south could migrated to the north of the fault zone through the unconformity and faults. Combined with the analysis of source reservoir cap rock assemblage and transport features, the reservoir forming assemblage characteristics of the coal formation gas source rock and fluvial facies compact sand in Yishan slope area which located in the south of the fault zone was determined to that the source is adjacent to the reservoir which is widely distributed, and in the inherited uplifted area which is in the north of the fault zone, local gas source condition is poor, but a side joint group with the source rock area in the south of the fault zone was formed in this area. The exploration area located in the quasi continuous discontinuous transition zone of the Permo Carboniferous in the north of the Ordos Basin, based on which two different types of natural gas reservoir forming models were established. The model in the south is “the adjacent of the source and reservoir and physical propertys controlling of reservoir”, the models in the north is “dual sources supplying of gas, traps controlling of reservoir”.