摘要:
郑庄区块山西组地层较薄,以K7和K8砂岩与上下地层分界,发育主煤层3号煤层。其沉积期处在陆表海背景下的海陆过渡演化阶段,发育了大面积的下三角洲平原沉积体系,主要沉积了分流河道、分流间湾、天然堤、沼泽等沉积相,三角洲前缘和前三角洲相不发育。在沉积环境分析的基础上,将山西组分为Ⅰ、Ⅱ、Ⅲ 3个砂组,进一步研究了区块沉积微相的平面展布及演化规律。在山西组的演化过程中,分流河道变宽且平直,分叉减少,河口砂坝沉积逐渐消失,自下而上沉积相呈现向陆过渡的特征。
Abstract:
The Shanxi Formation at the Zhengzhuang block is relatively thin and separated with upper and lower Formations by sandstone K7 and K8 and contains the No 3 main coal seam. It was formed in the transitional phase from an epicontinental sea to a land. A sequence of deltaic plain deposits, consisting of deltaic plain, distributary channel, interdistributary bay, natural levee, crevasse splay and swamp deposits, were developed in large area of the basin, even the delta front and prodelta deposits were not developed. According to the sedimentary environment, this paper divided the Formation into three sand groups (Ⅰ, Ⅱ, Ⅲ). Careful study has been made on the spatial distribution and evolution of micro-facies in this block. It is revealed that with the retreat of sea water, distributary channels become wider and more straight as bifurcates reduced and mouth bars gradually disappeared. Then the Formation changed into land facies at the upper part.
下载: