摘要
松辽盆地北部徐家围子断陷下白垩统沙河子组物源近、相变快、非均质性强、源储叠置发育,具备形成致密气藏的地质条件。研究表明:沙河子组储层致密,结构成熟度较低,储层流动孔喉半径下限为20nm,致密储层成储孔喉半径上限为0.4μm。沙河子组样品核磁共振与高压压汞分析揭示储层物性受沉积物粒径影响较大,首先按照致密砂岩、砂砾岩等不同岩性划分储层类型;然后根据单井产量受孔隙度、储层厚度、泥质含量等因素综合影响,创新了断陷盆地致密储层先分类、后分型的甜点评价方法。全区共划分31个甜点区、识别230个甜点体,断陷北部安达地区为首选甜点区,扇三角洲前缘水下分流河道微相、席状砂微相、河口沙坝微相甜点体更发育,为勘探部署提供了指导。
Reservoir of the Lower Cretaceous Shahezi Formation in Xujiaweizi Fault Depression in the northern Songliao Basin is characterized by close provenance, rapid facies change, strong heterogeneity and superimposed source rock and reservoir, which has geological conditions for the accumulation of tight gas reservoir. The study results show that reservoir of Shahezi Formation is tight with low textural maturity. The lower limit of pore throat for fluid flow is 20 nm and the upper limit of pore throat is 0.4 μm of the tight reservoir. NMR and high pressure mercury injection experiments on core samples of Shahezi Formation indicate that the reservoir physical properties were greatly affected by sediment grain size. Firstly, the reservoir types are classified according to different lithologies such as tight sandstone and glutenite. Then the sweet spot evaluation method of “subdivision after classification” is innovatively researched for tight reservoirs in fault basin based on the comprehensive factors such as porosity, reservoir thickness, and shale content affecting on single well production. As a result, 31 sweet spot areas are divided in the entire area and totally 230 sweet spot bodies are identified. Among them, Anda area in the northern Xujiaweizi Fault Depression is an optimal sweet spot area, with sweet spot bodies of the underwater distributary channel, sheet sandstone and channel mouth bar microfacies of delta front facies are well developed, which provides guidance for the exploration deployment in this area.
作者
张大智
初丽兰
李鑫
王晓莲
Zhang Dazhi;Chu Lilan;Li Xin;Wang Xiaolian(Research Institute of Exploration&Development,PetroChina Daqing Oilfield Company)
出处
《中国石油勘探》
CAS
CSCD
北大核心
2022年第5期73-82,共10页
China Petroleum Exploration
基金
国家科技重大专项“致密气富集规律、资源潜力评价与有利目标优选”(2016ZX05047-001)
中国石油天然气股份有限公司重大科技专项“松北深层天然气富集规律、勘探技术研究与规模增储”(2016E-0203)。
关键词
徐家围子断陷
沙河子组
致密砂砾岩
甜点综合评价
勘探成效
Xujiaweizi Fault Depression
Shahezi Formation
tight glutenite
comprehensive sweet point evaluation
exploration result
