单县矿区高分辨率层序地层及成煤作用研究

A Study of High-resolution Sequence Stratigraphic Characteristics and Coal Accumulation in Upper Paleozoic Strata of the Shanxian Coalfield

运用高分辨率层序地层原理,通过岩心、测井资料的综合分析,对研究区上古生界进行了不同周期地层基准面旋回研究,识别出短期、中期、长期及超长期4种规模的地层旋回。通过对比分析,建立了该区高分辨率层序地层格架。研究表明,研究区成煤作用出现于基准面旋回的特殊位置(A/S接近于1),当叠置在长期基准面旋回下降半旋回和中期基准面旋回下降半旋回晚期是成煤的最有利时期。根据盆地充填演化和不同级次基准面旋回叠加可以将研究区成煤作用分为早期成煤作用和晚期成煤作用,依次分析了不同时期成煤作用的地层基准面变化和盆地沉积充填演化的过程。

Based on the principle of high-resolution sequence stratigraphy and an integrated analysis of the bore core and well logging, the authors divided different base level cycles of Upper Paleozoic strata in the study area. Four types of base level cycles were recognized： short, intermediate, long and extremely long. Through a comparative analysis, a high-resolution sequence framework was established. Researches show that the most favorable coal accumulation of the study area occurred at the special positions of the base level cycles （A/S close to 1）, i.e., at the haft level of the descending long base level and the late stage of the descending half level of the middle base level. According to the basin filling and the superimposition of different classes of base levels, the coal accumulation of the study area can be divided into early accumulation and late accumulation. The base level change of both accumulations and the course of basin filling evolution are analyzed in this paper.