陕西渭河盆地前新生界地质特征及其油气意义

    Pre-Cenozoic geological characteristics and oil-gas significance in Weihe basin, Shaanxi Province

    • 摘要: 渭河盆地位于鄂尔多斯地块与秦岭造山带的过渡地带,为新生代断陷盆地。依据渭河盆地沉积-构造演化过程、渭北隆起和秦岭造山带中新生代演化及隆升特点,结合钻井资料及水溶天然气同位素分析,综合探讨了渭河盆地前新生代地质特征。渭河盆地在前新生代应为秦岭造山带与鄂尔多斯盆地之间的古斜坡带,前新生界总体表现出边部老中间新的特点,其中北部斜坡区大部分以早古生代碳酸盐岩地层为主,中南部深凹陷区则广泛保留晚古生代石炭系—二叠系煤系地层,局部地区可能仍有中生代地层残留,暗示渭河盆地前新生界仍存在重要的潜在烃源岩。该认识对探讨渭河盆地的形成演化及天然气勘探具有重要意义。

       

      Abstract: The Weihe basin is a Cenozoic fault basin located at the junction of Ordos basin and Qinling orogrenic belt. In this paper, the pre-Cenozoic geological characteristics are discussed based on an integrated analysis of the sedimentary and tectonic evolution of Weihe basin, the evolution and uplift characteristics of the Weibei uplift and the Qinling orogenic belt during Mesozoic-Cenozoic period, the drilling data and the hydrocarbon gas of geothermal water isotope in the Weihe basin. It is considered that the Weihe area was a paleo-slope zone between Qinling orogenic belt and Ordos Basin with relatively older pre-Cenozoic groups at the edge and newer ones in the middle. Most of the northern slope zone of Weihe basin is occupied by the early Paleozoic carbonate, while in the south-central deep sags of Weihe basin, the late Paleozoic Carboniferous-Permian coal measures might be widely existent, with the local existence of Mesozoic strata, which are important potential source rocks in the Weihe basin. The results achieved by the authors are of great significance for the formation-evolution study of Weihe basin and its gas exploration.

       

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