库车坳陷索罕露头区与大北气田井下白垩系储层差异性分析

Analysis of Cretaceous Reservoir Differences between Suohan Outcrop and Dabei Gas Field in Kuqa Depression

利用露头来进行地下地层和储层研究,是目前国内外较流行的一种研究思路。本文通过对塔里木盆地库车坳陷大北气田井下巴什基奇克组第三段与其典型露头索罕露头区巴三段砂岩储层差异性分析认为,二者沉积相带一致,岩石学特征略有差异,但是在储集空间类型和储层物性上差异较大。差异原因在于索罕露头区巴三段较大北气田井下经历了浅埋藏、弱压实、弱挤压和现代风化淋滤。露头与井下储层的对比研究对于深入了解库车坳陷深层裂缝性致密砂岩储层性质,进而进行储层评价具有重要的理论和实际意义。

The analysis of Cretaceous Bashijiqike Formation 3rd member reservoir finds the similarities and differences between Suohan outcrop and Dabei gas field in Kuqa depression of Tarim Basin.They both have the similar depositional environment and characteristics： both of them mainly deposited fan delta frontal surfaces.Their petrological characteristics are of slightly different.But obvious difference exists in the reservoir property and reservoir space.The physical properties of outcrop are much better with the porosity of 13%~18% and the permeability of 1×10-3~100×10-3 m2 while the data of Dabei gas field are 2%~7% and 0.01×10-3~1×10-3 m2.Meanwhile the reservoir space types are drastically disparate.The reasons of the differences lay in that Bashijiqike formation 3rd member of Suohan outcrop has ever experienced from shallow burial,low compaction,weak exposure and modern weathering and leaching reformation which Dabei gas field has not.It has important significance to realize reservoir property and reservoir evaluation on tight sandstone and fractured reservoir in Kuqa depression.