苏里格庙盒8气层次生孔隙成因及孔隙演化模式探讨

鄂尔多斯盆地苏里格庙气田盒8气层处于晚成岩B期，普遍存在凝灰质等不稳定碎屑和填隙物，广泛发育各种类型的次生孔隙。为了探讨次生孔隙的成因，开展了地质条件及不同介质条件下的熔蚀模拟实验，运用环境扫描电镜同位扫描和能谱分析，对比溶蚀前后样品的成分，根据等离子发射光谱测定溶蚀后的水样成分，实验表明，含凝灰质砂岩的溶蚀量是石英砂岩溶蚀量的7～11倍，且溶蚀量随乙酸酸度增加而加大；长石溶蚀澡后于凝灰质溶蚀，长石含量对溶出量没有特别明显和影响。研究结论，盒8气层次生孔隙成因主要是蚀变凝灰质的溶蚀，并提出了含凝灰质砂岩的孔隙演化模式。

An approach to the generating mechanism of secondary pores and pore evolution model of He 8 gas layer in Suligemiao gas field

Suligemiao gas field is another significant discovery followed the discovery of Yulin gas field in Ordos basin, however porosity genesis type between He 8 gas layer in Suligemiao gas field and that of Shan 2 layer in Yulin gas field has greater diversity. Through digenetic research, the sandstones of He 8 interval are of B period of the late diagenesis. According to systematic petro mineral appraisal, environmental scan electron microscope analysis, and energy spectrum, it is found that tuffaceous, unstable debris and unstable fillings are very excessive. Different types of secondary porosity are extensive. In order to study the origin of the secondary pores, acidolysis simulating experiment, under simulating stratigraphic conditions, has been developed. By the means of environmental scan electron microscope analysis and energy spectrum analysis, the sample's variety before and after acidolysis corrasion has been contrasted. By the means of plasma emission spectrum analysis, the water sample's components after the acidolysis corrasion also have been tested. The results indicate that the tuffaceous sandstone's corrasion is very obvious, and the corrasion become serious as the acidity of acetic acid increased. The tuffaceous sandstone's corrosion capacity is 7.0 11.0 times that of the quartz sandstones. The felspathic corrosion lagged that of alter tuffaceous matrix. Through analy sis and research the author indicates that the main origin of the secondary pore is the corrosion of tuffaceous sandstone, and puts forward the new pore evolvement model of the tuffaceous sandstone.