黔东北地区震旦系-寒武系黑色页岩含气性分析——以铜页1井为例

Analysis on Gas-bearing Potential of Black Shale in Sinian and Cambrian in Northeast Guizhou——Take Tongye 1 well as an example

雪峰隆起西缘作为晚抬升型基底隆起带,寒武系牛蹄塘组经历深埋藏的持续时间相对较短,有机质演化程度普遍有利于页岩气保存,具有良好页岩气资源潜力。本文以黔东北地区铜页1井为例,通过分析寒武系牛蹄塘组和震旦系老堡组纵横向黑色岩系总有机碳含量、有机质成熟度、沉积厚度、优质页岩厚度等数据变化,探讨各参数与含气性差异的关系。基于对铜页1井的分析结果表明:牛蹄塘组富有机质页岩厚约56 m,TOC含量平均为4.49%;Ro平均值3.35%,总体达过成熟阶段;干酪根类型均为Ⅰ型,生烃潜力较好。脆性矿物含量>50%,储层孔隙度平均为0.81%,渗透率平均为0.37×10^(-3)mD,均较低,属于低孔超低渗储层。页岩孔隙多以孤立的不规则状溶蚀孔为主,有机质孔保存较差,孔隙连通性差。含气性测试显示,牛蹄塘组含气量总体较低,最高仅0.07 m^(3)/t,老堡组含气量最高仅0.33 m^(3)/t,老堡组含气性较牛蹄塘组相对更好。研究表明,牛蹄塘组有机质热演化程度越高,有机质孔及溶孔数量越少,储层连通性越差;储层岩性致密,缺乏可容空间,是牛蹄塘组含气性弱的主要因素。老堡组具有相对较好的页岩气显示,可能是牛蹄塘组底部的有机质受成岩后期改造,页岩气沿裂缝集中保存所致,具备一定的研究和开发利用价值。

The western edge of the Xuefeng Uplift,the Cambrian Niutitang Formation,is a late uplifted basement uplift zone and experienced a relatively short period of deep burial,and the degree of organic matter evolution is generally favorable for the preservation of shale gas,which is a good shale gas resource potential has an effect.In this paper,it takes the Tongye 1 well in northeast Guizhou as an example,and explores the relationship between each parameter and the difference in gas content by analyzing the changes in the data of TOC total organic carbon(TOC),organic matter maturity Ro,the sediment thickness,can be analyzed and thickness of high-grade shale in the Cambrian Niutitang formation and the Aurignacian Laobao formation in longitudinal and transverse black rock systems.Based on the analytical results of the Tongye 1 well,the results show the following:the organic-rich shale of the Niutitang Fformation is about 56 m thick,the average TOC content is 4.49%;the average Ro value is 3.35%,and the overall ripeness has reached the overripe stage;the types of kerogen are all typeⅠ,and the potential of hydrocarbon production is good.The brittle mineral content is>50%,the average porosity of the reservoir is 0.81%,and the average permeability is 0.37×10^(-3)mD,which is low,and it is one of the low porosity and extremely low reservoirs Permeability.The shale pores are largely dominated by isolated,irregularly shaped dissolution pores,with poor preservation of organic material pores and poor pore connectivity.The gas content test shows that the Niutitang formation generally has a lower gas content,the highest is only 0.07 m^(3)/t,and the highest is only 0.33 m^(3)/t in the Laobao formation,and the Laobao formation has better gas content than the Niutitang formation.The study shows that the higher the degree of thermal evolution of organic matter in the Niutitang Formation,the fewer of organic matter pores number and soluble pores and the worse the connectivity of the reservoir;the lithology of the reservoir is dense and lacks space,which is the main factor for the weak gas content of the Niutitang Formation.The Laobao Formation has relatively good shale gas reserves,probably because the organic matter at the bottom of the Niutitang formation is modified by the late stage of diagenesis,and the shale gas is centrally preserved along the fractures,which has a certain value for research,exploration and development.