塔里木盆地库车坳陷克拉苏构造带深层致密砂岩气藏储层致密化与成藏关系

The relationship research between densification of reservoir and accumulation of the deep tight sandstone gas reservoirs of the Kelasu tectonic zone in Kuqa Depression,Tarim Basin

为研究深层致密砂岩气气藏储层致密化与成藏的关系,对塔里木盆地库车坳陷克拉苏构造带的地质背景和储层特征进行分析,建立储层孔隙度与埋深的关系模型,推算储层致密化时间。利用流体包裹体均一测温分析技术,分析该区大北1、克深2深层致密砂岩气藏的成藏期次,并与储层致密化时间相比较,确定深层致密砂岩气藏的成因类型。研究表明,大北1气藏表现为晚期充注成藏的过程,其天然气成藏时间主要在库车期(约3~2Ma)以来,其白垩系巴什基奇克组砂岩储层致密化发生在新近纪康村期(约15~10Ma);克深2气藏也表现为晚期充注成藏过程,其天然气成藏主要发生在库车晚期(约2Ma)以来,而其巴什基奇克组砂岩储层在新近纪康村期(约11~10Ma)已经达到致密化。据此,确定大北1和克深2深层致密砂岩气藏类型属于"先致密后成藏型"。

To study the relationship of densification of reservoir and accumulation of deep tight sandstone gas reservoirs,the geological background and reservoir characteristics of Kelasu tectonic zone in Kuqa Depression were analyzed,the relation model of reservoir porosity and burial depth was established to calculate the time of reservoir densification.Using the homogenization temperature analysis technique of fluid inclusion,the accumulation period of deep tight sandstone gas reservoir in Dabei 1 and Keshen 2 gas reservoirs was analyzed.Combined with the reservoir densification time,the formation type of deep tight sandstone gas reservoir was comfirmed.Research shows that Dabei 1 gas pool is characterized by late period gascharging reservoir process,where the gas reservoir formed since Kuqaperiod（about 3-2 Ma）,and the densification of Cretaceous Bashijiqike Formation sandstone reservoir occurred in the Kangcun period of Neogene（about 15-10 Ma）.Keshen 2 gas reservoir also showed a characteristic of late period gas-charging process,which occurred in the late Kuqaperiod（about 2 Ma）,while the Bashijiqike Formation sandstone reservoir in the Kangcun period of Neogene（about 11-10 Ma）has reached the densification.And accordingly the research,determined the Dabei 1 and Keshen 2 deep tight sandstone gas reservoirs as＂early densification and later accumulation type＂.