惠民凹陷商河地区沙一段碳酸盐岩沉积特征

惠民凹陷商河地区沙一段发育多层碳酸盐岩沉积。经研究发现 ,这些碳酸盐岩成分以白云石为主 ,其沉积相类型包括滨湖亚相、生物浅滩亚相、滩缘亚相和半深湖亚相。生物浅滩具有分布范围广阔、顶面平坦、进积迅速、前斜坡明显、沉积旋回发育、沉积厚度较小但稳定的特征。在快速进积的过程中 ,浅滩表面水体循环不畅并逐渐淡化 ,从而形成大量次生孔隙。早成岩期孔隙中沉淀的方解石是岩石的主要胶结物和灰质成分。生物浅滩的这种沉积和成岩特征对该段碳酸盐岩油气藏具有明显的控制作用

Sedimentary characters of carbonate rock of shahejie formation in Shanghe area of Huimin sag

Many layers of carbonate rock deposition existed in the first member of Shahejie formation in Shanghe area of Huimin sag. Dolomite is the main composition of the carbonate rock. The sedimentary facies relating with carbonate rock include lakeshore, bank, bank margin, bathyal lake subfacies. The biology bank facies has the features of wide distribution, planar surface, rapid retrograding, obvious foreslope, excesive cycles, thin and stable rock layers. The water on bank surface was not expedient in circulation and gradually desalted, and plenty of pores were formed in the process of quick progradation of bank. The calcite deposited in pores during early stage of diagenesis was the main cement and ash composition of rock. The sedimentary and diagenesis characters of biology bank facies obviously controlled oil and gas bearing reservoir of carbonate rock in the first member of Shahejie formation.