琼东南盆地崖13-1气田陵三段沉积微相对储层非均质性及流动单元划分的影响

The influence of depositional facies on reservoir heterogeneities and flowing zone division in the 3rd Member of Lingshui Formation of Ya13-1 Gas Field in QDN Basin

崖13-1气田陵三段是河控与潮控的辫状三角洲,主要储层沉积微相为分流河道、水下分流河道、河口坝、远砂坝及席状砂,其中河口坝的储层物性比分流河道和水下分流河道微相好,席状砂与远砂坝的物性相对较差,而各类正韵律河道与反韵律的砂坝决定了各垂向流动单元储层韵律特征。气田内的隔夹层与不同规模的海泛面相关,隔层以前三角洲泥为主,分布稳定,而夹层以分流间湾与水下分流间湾泥为主,分布较局限。结合沉积微相分布、储层非均质性及断层的分布,可以把气田区分为两个大区及6个流动单元,而南II、南III区仍可有较好的储层,但由于构造上处于低部位,含气前景还需进一步论证。

The depositional facies of the 3rd Member of Lingshui Formation is braided delta controlled by fluvial and tidal processes. Moreover,the main depositional micro-facies of reservoir include distributary channel,subaqueous distributary channel,river mouth bar,distal bar and sheet sand,in which mouth bar＇s reservoir properties are better than that of distributary channel and subaqueous distributary channel; meanwhile,the reservoir properties of distal bar and sheet sand are relatively poor. Furthermore,the reservoir rhythm characteristics of vertical flowing zone are dominated by channel coarsening upward and sand bars fining upward. The interlayers and intercalations in the gas field are related to the flooding surfaces of different scales. The interlayers are mainly prodelta shales which distribute widely; however,the intercalations are mainly subaqueous distributary bay shales whose development is restricted. Integrating the depositional micro-facies distribution,the reservoir heterogeneity and the fault distribution,the gas field can be divided into two vast areas including six planar flowing zones. According to the depositional distribution,there are some good reservoirs in the second and third block of the south area in the gas field,but the prospect of gas bearing should be demonstrated further because those blocks are at the low parts of the gas field structure.