平衡深度法恢复鄂尔多斯盆地延长组过剩压力探讨

借鉴延长组长7段泥岩孔隙微观结构研究成果,应用核磁共振测井孔隙结构评价技术,结合岩相学观察,对欠压实段泥岩孔隙微观结构和孔隙度特征进行分析,探讨平衡深度法恢复鄂尔多斯盆地延长组地层异常压力的适用性。结果表明:核磁共振孔隙结构评价、孔隙结构观察及定量分析、孔隙度实测均不支持延长组长7欠压实段泥岩存在异常高原生粒间孔或孔隙度,其声波时差偏离正常压实趋势曲线,不能反映该段存在异常高原生粒间孔或孔隙度,平衡深度法计算最大埋深期异常压力不适用。

Equilibrium depth method to restore Yanchang formation pressure of Ordos basin

With reference to mudstone porosity microstructure research results of Chang-7 segment of Yanchang formation,by applying nuclear magnetic resonance(NMR)logging evaluation technology of pore structure,combined with petrography observation,the analysis on mudstone undercompaction porosity and pore microstructure characteristics has been carried out,and the applicability of the equilibrium depth method to restore the abnormal Yanchang formation pressure of Ordos basin has been discussed.The results show that the nuclear magnetic resonance(NMR)evaluation of pore structure,pore structure observation and quantitative analysis,the measured porosity does not support the existence of abnormal plateau intergranular pore and porosity in undercompaction of Chang-7 segment of Yanchang formation.The acoustic transit time deviated from the normal compaction trend curve,and it can't reflect the segment abnormal plateau intergranular pore and porosity,and the equilibrium depth method to calculate the maximum phase embedded depth of abnormal pressure is not applicable.