The Study Of Fuyu Oil Layer’s Fracture Development Characteristics In Daan Oilfield

Daan oilfield locates in honggang terraces of the secondary structural belt in the central depression area of songliao basin. Purpose layer is fuyu oil layer in the lower cretaceous quantou formation, which is a typical low permeability sandstone oilfield. It have poor reservoir property, strong heterogeneity, complex fractures, it is crucial for oil and gas distribution and seepage. Therefore, the research on the development rules of the oil field has great effect on the development plan design and analysis of development.We obtained following knowledge from this paper:(1) The general characteristics of reservoir property in the study area has shown that it have poor reservoir property, mainly for low hole porosity, low permeability tight reservoir. Studies show that pore throat radius has obvious control effect on permeability, porosity has good correlation with permeability, separation and connectivity have complicated relationship with prrosity and permeability. Fuyu reservoir in Dan an oilfield mainly develop diagenetic and regional tectonic cracks, scale mainly for micro cracks.(2) Fracture is mainly controlled by three factors: The embodiment of the fracture effect on the physical properties may be more in terms of fracture distribution, and little influence on pore; Sedimentary environment is the premise of reservoir physical properties. Different lithology and physical properties of sedimentary microfacies, different mechanical properties of sedimentary microfacies are different, leading to the obvious different degree of fracture development. The late diagenesis has great effect on fractures improvement, The local uplift of fuyu reservoir and acid oxidation of surface water intensifies the dissolution.(3) The study area develops typical tight reservoir, with typical dense oil, quasi continuous distribution, enrichment of dessert, low and complex oil-bearing abundance distribution. According to core data and logging data, core oil level division is divided into five levels, oil, immersion, oil sport, oil trace and fluorescence. Reservoir percolation ability increases with the increase of the movable fluid saturation. We established the movable fluid saturation and porosity and permeability of the regression relations by studying, and quantitatively evaluated movable fluid saturation and reservoir percolation ability size. Microfracture in the reservoir is the main factors of movable fluid reservoir and seepage ability of the size. The cracks can effectively improve reservoir percolation capability(4) Both structural fractures and non-structural seam, they improve the performance of tight sandstone reservoir. They could serve as reservoir space and hydrocarbon migration channel. Cracks can communicate the original reservoir pore. It can obviously improve the permeability of reservoir. Reservoir quality gets improved. Cracks can be used as a good reservoir. When hydrocarbon is sheltered by mudstone in the process of migration, mudstone accumulated with overpressure, growth and cracks. Hydrocarbon eject through the mudstone fracture, pressure release later.and mudstone internal micro fracture closure. As pressure gathered again, hydrocarbons intermittently expelled through microcracks, it can achieve the congregation of oil migration.