准噶尔盆地西北缘侏罗系含煤和非煤储层差异性

Differences Between Coal-bearing and Non-coal Reservoirs in Jurassic in the Northwest Margin of Junggar Basin

为了明确造成准噶尔盆地西北缘侏罗系煤系与非煤系砂岩储层物性明显差异的因素,需依据分析测试资料,开展研究区2种储层储集空间类型、储层影响因素和孔隙演化规律等方面的分析和对比。结果表明,非煤系储层的物性特征明显好于煤系储层,但这两种储层的储集空间类型和组合特征一致,均以原生粒间孔为主,颗粒溶蚀孔隙次之;影响储层减孔量的主要因素为压实作用、砂岩成熟度、塑性岩屑含量以及沉积物粒度等,其中压实是破坏储层孔隙的主要因素;由于煤系储层水介质为酸性,造成长石和岩屑溶蚀,因此,煤系储层早期的压实作用造成的减孔量更大。

In order to find out the factors that cause the obvious difference of physical properties between Jurassic coal series and non coal series sandstone reservoirs in the northwest margin of Junggar basin,based on the analysis and test data,the reservoir space types,reservoir influencing factors and pore evolution rules of the two kinds of reservoirs in the study area are compared and analyzed.The results show that the physical properties of the non coal reservoirs are better than those of coal bearing reservoirs,but the types and combination characteristics of the reservoir space of the two types of reservoirs are consistent,and the primary intergranular pore is their main reservoir space,followed by the particle dissolution pore.The main factors affecting the porosity reduction are compaction,sandstone maturity,plastic debris content and sediment size.Among them,compaction is the main factor to destroy reservoir pores.Because the water medium of coal series reservoir is acid,which causes feldspar and debris to dissolve,the early compaction of coal series reservoir results in more pore reduction.