姬塬地区上三叠统长_2、长_1储层成岩作用研究

根据普通薄片、铸体薄片、扫描电镜等资料的分析,并以此为基础对该区成岩作用进行了深入的研究。确定了姬塬地区长_2、长_1储层的成岩阶段,建立了成岩演化模式,研究了主要成岩作用对储层性质的影响。研究结果表明,该区成岩作用主要包括压实作用、碳酸盐胶结、绿泥石胶结、高岭石胶结、石英加大、火山物质溶蚀和长石、岩屑颗粒的溶蚀等;该区储层的成岩演化目前已经达到了晚成岩A期,以次生溶蚀孔隙为主;成岩作用对本区砂岩储层起着重要的控制作用,研究地区因砂岩粒度较细,成分成熟度低,因此压实作用较强,是造成孔隙减小最重要的因素。火山物质和长石岩屑颗粒的溶蚀是孔隙发育的关键。同时晚期方解石、铁方解石等碳酸盐胶结物又使砂岩孔隙再度降低。

Diagenesis study of the chang 2 and chang 1 reservoirs of the upper triassic in the jiyuan oilfield

Based on analysis of common rock slice,casting lamella and scanning electron microscope data,this paper further studies the diagenesis of this area.Diagenetic stage is determined of the Chang 2 and Chang 1 reservoirs in the Jiyuan oilfield,A diagenetic evolution model is established and the effect of the main diagenesis on reservoir quality is studied.The result shows that the diagenesis in this area mainly includes compaction、Carbonate cementation、Chlorite cementation、Kaolinite cementation、quartz secondary、volcanics denudation、feldspar and debris particles denudation.Diagenesis of this reservoir reaches A-period of late diagenetic stage,secondary dissolution pore is the main pore form. Digenesis has control of succession of controlling to sandstone reservoirs in the region. Because the size of sand particle in this study areas is smaller and low compositional maturity,this area has a strong compaction.This is the most important factor to result in reduced porosity.Volcanic material and debris particles of feldspar dissolution are the key to porosity development.At the same time,such as the late calcite,rail calcite of carbonate cement made sandstone porosity reduced once again.