勘探评价早期阶段沉积微相研究方法探讨——以东濮凹陷前梨园南地区为例

Research of Sedimentary Micro-facies at the Early Stage of Exploration Evaluation——By Taking South Qianliyuan Area in Dongpu Depression for Example

为了提高勘探评价早期阶段的沉积微相研究精度,以东濮凹陷前梨园南部沙河街组沙三中亚段5砂组为例,对沉积微相研究方法进行了探讨。首先,通过岩心观察、单井沉积微相分析,结合研究区沉积特征,将三角洲前缘亚相划分出水下分流河道、水下分流间湾、坝、席状砂4种主要微相。统计单井的微相厚度和累计分布概率,建立定量地质知识库,估算各微相的平面延伸范围和分布规律。随后,进行地震属性提取与组合优选,建立优选属性组合与含砂率的拟合关系,结合实际井资料,综合编制含砂率等值线。最后,以单井含砂率与优势沉积微相的统计关系为基础,以定量地质知识库为约束,结合含砂率等值线,刻画研究层段的平面沉积微相,为早期勘探评价提供了高精度的沉积微相图。

In order to enhance the precision of sedimentary micro-facies analysis at the early stage of exploration evaluation,by taking Zhong 5 Sand Group of the middle member of Es3 in the south of Qianliyuan Area for example,methods for studying the sedimentary micro-facies at the early stage of exploration were discussed.Based on core observation and sedimentary micro-facies analysis of single well,four major sedimentary micro-facies including subwater distributary channel,subwater interdistributary bay,mouth bar and sand sheet were identified in combination with sedimentary characteristics in the studied area.According to the statistical data of sedimentary micro-facies thickness in single well and cumulative frequency distribution,a quantitative geological knowledge database was established to estimate the extended range in plane and distribution rules of each sedimentary micro-facies.Several seismic attributes were extracted and optimal attributes were obtained to build the fitting relationship between optimal attribute assembly and sand containing factors.Then,contour of sand factor was made by using integrated well logging data.Finally,based on statistical relationship between sand factor in single well and dominated sedimentary micro-facies,restricted by the quantitative geological knowledge database and combined with the contour of sand factor,sedimentary micro-facies of target zones is described,it provides high resolution sedimentary micro-facies map for the exploration at the early stage.