Pressure propagation of ultra-low permeability reservoir and resonable well pattern research of Chang 8 formation

Chang 8 formation of Zhenjing oilfield belongs to low porosity and ultra-low peameability reservoir, and in accordance with reservoir classification standard, it can be classified into pore type and fracture type reservoirs. In order to make a study on the matching relationship between pressure propagation and well pattern of different reservoir types, the analysis of typical oil well dynamic index has been carried out, and then the reservoir pressure propagation characteristics and resonable well pattern for different types have been determined. With integrated application of vector well pattern and numerical simulation methods towards different wells, the plan has been predicted so as to determine resonable well spacing. The results show in pore type reservoir, oil wells have the characteristics of low initial production, quick decline, low pressure propagation, and the injection ability of a injector decreases with the increase of water injection volume, while in fracture type reservoir, the producing wells have the characteristics of high initial production, slow decline, strong water absorbing capacity and the water injectivity index has obvious inflection point. Therefore, in pore type reservoir, diamond back nine o 'clock pattern is deployed with reasonable well spacing range of 450～500 m. In fracture type reservoir, rectangular pattern (determinant) is deployed with reasonable well spacing range of 130～150 m.