安徽巢湖—南陵地区栖霞组碳酸盐岩定量微相分析

Quantitative Microfacies Analysis of the Carbonate of Qixia Formation in the Chaohu-Nanling Aera,Anhui Province

安徽巢湖—南陵地区栖霞组地层较为发育,厚度稳定,具有较高的有机质含量和良好的孔隙度。前人对本区栖霞组碳酸盐岩的微相研究均为定性的工作,因此,定量分析栖霞组碳酸盐岩的微相特征对其沉积相的进一步确定及油气资源的预测与勘探均具有重要的意义。栖霞组中第一段为斜坡中部沉积,颗粒和开阔海生物含量及颗粒/基质比最高,分别为35.65%、0.43%和0.70;第二段为斜坡下部沉积,颗粒含量和颗粒/基质比值最小,分别为24.69%和0.38,开阔海生物含量也最高,为0.43%;第三段为开阔台地沉积,具有较高的颗粒含量和最低的开阔海生物含量,分别为32.68%和0.34%;第四段为斜坡中上部沉积,具有较高的颗粒含量和颗粒/基质比,分别为29.91%和0.52,开阔海生物含量为2.39%。该结论与以往认识一致,进一步佐证了前人的研究成果。

The Strata of Qixia Formation is well developed in Chaohu-Nanling Area of Anhui Province, with constant thickness, high content of organic matter and the porosity. Previousy study of the carbonate Qixia Formation in this ar- ea is essentially qualitative. Therefore, quantitative microfacies analysis of the carbonate in Qixia Formation is signifi- cant to confirm the sedimentary facies, predict and explore the gas and oil. In Qixia Formation, the first member de- posits in the middle carbonate slope, with the highest grain, open-sea biota content and grain/matrix ratio, which are 35.65%, 0.43% and 0.70, respectively; The second member deposits in lower carbonate slope, with the lowest grain content, grain/matrix ratio, which are 24.69% and 0.38, and also highest open-sea biota content, that is 0. 43%; The third member deposits in open carbonate platform, with higher grain and the lowest open-sea biota con- tents, which are 32.68% and 0.34%, respectively. The fourth member deposits in middle-upper slope, with higer grain content and grain/matrix ratio, which are 29.91% and 0.52, respectively, and the content of open-sea biota is 2.39%. This conclusion is consistent with the previous one, further supporting the previous research.