赣东北地区下寒武统荷塘组页岩气保存条件分析

通过剖面测量等野外地质调查手段和"X"射线衍射分析等室内实验测试方法,分析了赣东北地区下寒武统荷塘组页岩气赋存的物质基础、孔隙特征、演化特征及构造发育特征等地质条件,在确认了下寒武统荷塘组页岩具有良好生烃条件的前提下,重点研究了荷塘组页岩气的保存条件及其差异性。研究结果表明:研究区页岩气保存条件整体良好,下寒武统荷塘组页岩含气量在(1.0~5.0)m3/t之间;受构造和岩浆活动的影响,不同地区页岩气保存条件存在差异;扬子地块、上饶地块及怀玉山区块在断裂、岩浆活动及成岩作用综合影响下,页岩层构造变形程度大,完整度遭到一定破坏,页岩气保存条件相对较差;玉山区块受后期构造运动影响小,岩浆活动弱,褶皱相对宽缓,下寒武统荷塘组页岩埋深和厚度大,页岩气保存条件相对较好。

The analysis of shale gas preservation conditions of the lower Cambrian Hetang Formation in the Northeastern of Jiangxi

The material basis of the shales of the lower Cambrian Hetang Formation, pore characteristics, the evolution characteristics, tectonic development features and other geological conditions are analyzed by profile measurement and other geological exploration methods and and other experimental testing methods. The preservation conditions and differences of the shales of the Hawthorn Formation are focused on in confirmation of the shales of the Lower Cambrian Hetang Formation having a good hydrocarbon conditions. The results show that the gas content of lower Cambrian Hetang Formation shales is between 1.0m3/ t ~ 5.0m3/ t, which determines the preservation conditions of shale gas is overall good. Affected by tectonic and magmatic activity, there are some differences in different areas in shale gas preservation conditions. Under the combined effects of three blocks, magmatic activity and diagenesis in Yangtze tectonic plate, Shangrao tectonic plate and Huaiyu mountain block, the deformation degeree of shales becomes larger and its integrity has suffered some damage, which is not conducive to the preservation of shale gas. Yushan block is little impacted by post-tectonic movement and magmatism and its fold is relatively wide and gentle. The depth and the thickness of lower Cambrian Hetang Formation is larger ,which makes Yushan block have better preservation conditions.