吉林营城盆地构造演化与聚煤规律

Structural Evolution and Coal-accumulating Pattern in Yingcheng Basin, Jilin

松辽盆地群是我国最大的油气聚集区,营城盆地位于其东部,是松辽盆地群中一个典型的聚煤盆地。松辽盆地群基底构造及构造演化控制着营城盆地的演化和聚煤作用。营城盆地含煤层序为SE3层序,相当于沙河子组,可进一步划分为三个体系域:盆地充填体系域、盆地扩张体系域和盆地萎缩体系域。聚煤作用发生在盆地扩张体系域,为盆地扩张超覆沉积阶段的产物,发育Ⅰ～Ⅲ煤层组。Ⅲ煤层组厚度大,煤层稳定,几乎全区发育,是盆地初始充填体系域和扩张体系域转化期的产物。富煤带分布于上家—饮马河东西向隆起带,呈EW向展布,煤层向凹陷区分叉、尖灭。盆缘断裂构造的差异活动以及盆地构造演化是聚煤作用的主控因素。

The Songliao basin group is the largest oil and gas accumulating area in China, the Yingcheng Basin is located right in its eastern part, an unusual typical coal-accumulating basin. Basement tectonics and structural evolution controlled the evolution of the basin and coal accumulation. Coal-bearing sequence is the SE3, an equivalent of the Shahezi Formation, can be further divided into basin-filling, basin-expanding and basin-shrinking 3 systems tracts. The coal accumulation has happened in the basin-expanding systems tract, or the basin-expanding overlap depositional period, and I-III coal groups were developed. The III coal group has large thickness and stable, almost developed in whole area, is a production ibrmed in the basin-filling systems tract initial period and basin-expanding systems tract transitional period. The coal-rich zone is distributed in the Shangjia-Yinmahe EW up-warping zone, coal seams are bifurcating and thin out toward the down-warping regions. Differential movements of basin-margin faults and basin structural evolution are the main controlling factors of coal accumulation.