塔里木盆地塔中地区地质热历史研究

为了解塔里木盆地以及塔中地区构造演化史 ,对塔中地区古地温梯度的变化趋势进行了研究 ,利用磷灰石裂变径迹与镜质体反射率反演计算了塔中地区 3口井的地质热历史 .结合前人研究成果 ,认为塔中地区自古生代以来古地温总体呈下降趋势 ,其间存在两个相对较高的古地温期 ,一个是寒武纪—早奥陶世 ,另一个是二叠纪 ;早古生代塔中地区古地温梯度较高 ,寒武纪—早奥陶世地温梯度为 3 .2～ 3 .5℃ / 1 0 0m ,此后地温梯度显著下降 ;石炭纪古地温略有上升 ,二叠纪时地温梯度可能达到 3℃ / 1 0 0m ;中生代古地温梯度平缓下降 ,中生代末地温梯度 2 5℃ / 1 0 0m左右 ;新生代地温梯度变化不大 ,现今地温梯度 2 2℃ / 1 0 0m左右

Study on thermal history of Tazhong area,Talimu Basin

The study on the thermal history in Tazhong area is the indispensable composition of the studies on hydrocarbon-generating history and reservoir forming history and resource evaluation. Thermal histories of three wells of TC1, TZ12 and TZ45 in this area are obtained by the inversion calculation of the measurement data of fission track and vitrinite reflectance. The comprehensive research results of the authors and previous researchers show that, since Paleozoic Era, palaeo-geotherm in Tazhong area has decreased on the whole, but there are two higher palaeo-geotherm stages——Cambrian to early Ordovician period, and Permian period. The palaeo-geotherm gradient is 3.2～3.5 ℃/100m in early Ordovician Period and Cambrian Period, and it decreases distinctly from then on. In Carboniferious Period, the palaeo-geotherm increases a little, and the palaeo-geotherm gradient could be up to 3 ℃/100m in Permian period. In Mesozoic Era, the palaeo-geotherm gradient steadily decreases, and it is about 2.5 ℃/100m at the end of Mesozoic Era. In Cenozoic Era, the gradient changes a little. Now, it is about 2.2 ℃/100m.