奈曼旗凹陷奈1区块九佛堂组储层特征

为扩大油气勘探开发领域，中国石油辽河油田公司已将其工作范围延展到辽河油田的外围盆地。其中，开鲁盆地奈曼旗凹陷奈1区块下白垩统九佛堂组上段具备良好的生储条件，油气勘探开发潜力较大，但针对该区主力产层九佛堂组上段的沉积相和储层特征仍缺乏深入细致的研究，制约了油气开发工作的快速推进。为此，基于前人的研究成果，结合岩心分析化验、钻井、测井等资料，对九佛堂组储层进行了综合研究。结果认为：①奈1区块九佛堂组上段属扇三角洲沉积体系，可划分出扇三角洲前缘亚相以及分流间湾、分流河道侧缘、河口坝和水下分流河道等沉积微相；②储层孔隙类型主要为溶孔和残余粒间孔，微孔也占一定比例，整体上属中-低孔隙度、低-特低渗透率储层；③沉积微相、岩性和成岩作用控制储层发育，其中水下分流河道为最有利的储集相带，其次为河口坝；④长石、石英次生加大以及自生矿物充填作用对储层起破坏作用；⑤次生溶蚀作用虽对储层发育有利，但贡献不大。

Reservoir characteristics of the Jiufotang Formation in Nai-1 block of the Naimanqi Depression,Kailu Basin

The PetroChina Liaohe Oilfield Company has expanded its exploration field to the peripheral basins of the Liaohe Oil Field, among which the Kailu Basin is the most prospective one. In this basin, the Upper Jiufotang Fm of the Lower Jurassic in the Nai 1 block in the Naimanqi Depression has good source and reservoir conditions. However, no systematic research has ever been carried out on the sedimentary facies and reservoir features of this study area. Therefore, based on the previous study results and in combination with core, drilling and logging data, we performed a comprehensive study of the Jiufotang Fm reservoirs. The following conclusions are drawn. (1) The Upper Jiufotang Fm belongs to a fan delta sedimentary system which can be divided into fan delta frontal subfacies and several microfacies like interdistributary bay, lateral border of underwater distributary channel, mouth bar and underwater distributary channel. (2) Reservoir pore types are dominated by dissolution pores and relic intergranular pores and certain micropores. They are reservoirs of moderate low porosity and low ultra low permeability. (3) Sedimentary microfacies, lithology and diagenesis control reservoir development. Underwater distributary channel is the most favorable reservoir facies, followed by mouth bars. (4) Feldspar and quartz overgrowth and authigenic mineral infilling have an adverse effect on reservoir development. (5) Although secondary dissolution is constructive to reservoir development, but its contribution is limited.