保存条件对四川盆地及周缘海相页岩气富集高产的影响机制

发布时间：2018-08-19 09:38

【摘要】：以四川盆地及周缘牛蹄塘组和五峰组—龙马溪组2套页岩层为研究对象,通过对不同地区、不同含气性和产量的典型页岩气井进行解剖,探讨了影响页岩气保存条件的主控因素及评价体系。研究认为:顶底板条件、页岩自身封盖作用是该区页岩气早期滞留于页岩内的关键因素,后期构造改造强度与所持续的时间对页岩气藏的含气丰度具有明显的调整作用;保存条件对页岩气层的含气量、孔隙度、含水饱和度、电阻率以及页岩气气体组分等有明显的影响,保存条件差,页岩气层含气量、孔隙度、电阻率通常较低,含水饱和度、N2含量则较高,这些被影响的参数可以作为评价页岩气保存条件优劣的间接指标。建立了四川盆地及周缘复杂构造区下古生界海相页岩气5大类、28项参数的保存条件综合评价指标体系,即主要是封盖条件、页岩气层自身封堵性、构造作用(构造改造时间、断裂作用、地层变形强度等)等条件在时间和空间上的组合关系,另外页岩气层含气性表征参数和压力系数同样可在一定程度上指示保存条件的优劣。
[Abstract]:Taking two sets of shale formations in Sichuan Basin and its surrounding Niutetang formation and Wufeng formation and Longmaxi formation as research objects, the typical shale gas wells with different gas content and output in different regions were dissected. The main controlling factors and evaluation system of shale gas preservation conditions are discussed. It is concluded that the sealing of shale itself is the key factor for early retention of shale gas in this area under roof and floor conditions, and that the strength and duration of late structural transformation have a significant effect on the gas abundance of shale gas reservoir. The preservation conditions have obvious influence on the gas content, porosity, water saturation, resistivity and gas composition of shale gas reservoir. The gas content, porosity and resistivity of shale gas reservoir are usually low. The N _ 2 content of water saturation is higher, and these affected parameters can be used as an indirect index to evaluate the preservation conditions of shale gas. A comprehensive evaluation index system for the preservation conditions of 28 parameters of 5 major types of Lower Paleozoic marine shale gas in the Sichuan Basin and its surrounding complex tectonic areas is established, namely, the main sealing conditions, the shale gas reservoir plugging property, the tectonic process (the time of structural transformation, etc.) The combination relationship between time and space of the conditions such as fracture and deformation intensity of formation etc. In addition, the parameters of gas bearing characterization and pressure coefficient of shale gas reservoir can also indicate the advantages and disadvantages of the preservation conditions to a certain extent.
【作者单位】：中国石化勘探分公司;
【基金】：中国石化科技部基础研究项目(P15074) 中国地质调查局地质调查项目(12120115003901)资助
【分类号】：P618.13

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