川西邛崃县白马庙气田上侏罗统蓬莱镇组高分辨率层序地层分析

Analysis of high-resolution sequence stratigraphy of the Upper Jurassic Penglaizhen Formation in the Baimamiao gas field,Qionglai County,Western Sichuan

以高分辨率层序地层学理论及其技术方法为指导,通过地表露头、岩心、测井和地震资料的综合分析,在白马庙气田上侏罗统蓬莱镇组识别出3类不同成因类型和发育规模的层序界面、3个级别的湖泛面,划分出2个长期、6个中期、38～40个短期基准面旋回层序,并对不同级次旋回层序的特征进行了详细讨论。同时,发现中期基准面旋回层序近顶部的薄层灰岩和钙质泥岩也是识别中期基准面旋回的重要标志之一。在此基础上,运用旋回等时对比法则对各级次旋回层序进行对比,建立了3个不同时间尺度的等时地层格架,认为开展高分辨率层序地层分析对深化白马庙气田蓬莱镇组气藏的勘探开发工作具有重要意义。

Under the guidance of the theory and techniques of high-resolution sequence stratigraphy, through a comprehensive analysis of the outcrops, rock cores, well logs and seismic data, 3 sequence boundaries of different genetic types and growth scales and 3 orders of lacustrine flooding surfaces are recognized in the Upper Jurassic Penglaizhen Formation in the Baimamiao gas field, and in addition, 2 long-term base-level cycles, 6 middleterm base-level cycles and 38-40 short-term base-level cycles are distinguished and their characteristics are discussed in detail. The thin-bedded limestone and calcareous shale close to the top of the middle-term base-level cycle can be regarded as one of the important indicator for recognizing the middle-term base-level cycle. On the basis of the above, using the method of cycle isochronostratigraphic correlation, different orders of base-level cycles are correlated and 3 isochronostratigraphic stratigraphic frameworks with different time-scales are established. The high-resolution sequence stratigraphic analysis has great significance for further exploration and development of the gas accumulations in the Penglaizhen Formation of the Baimamiao gas field.