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The distribution of charge density on the surface of microscopic tight oil is studied by using Stern double electric layer theory, and the mathematical flow model of polar fluid with micro powers in tight oil reservoir is established. The Fourier transform infrared (FTIR) were used to investigate the interaction of rock surface functional groups with fluids. The results show that: (1) When the external fluid of the polar group passes through the dense micro-nano pore, it will form an electric double layer on the surface of the rock, there will be a certain thickness of the liquid membrane, the fluid migration has a certain Of the electrical viscosity effect, will have a certain flow resistance. (2) The Fourier transform infrared spectroscopy of the Chang 7 tight reservoir rock samples exists and distributes different kinds of peaks. The left peak trend determines the presence of hydroxyl groups. The four fronts and types of the right side can be used to obtain that calcium carbonate CO3 2- exists. (3) There are CO3 2- and hydroxyl functional minerals in the Chang 7 tight sandstone samples. It is consistent with the basic mineral analysis measured by X-ray diffraction. When the external fluid affects the rock surface, the surface will occur in the physical van der Waals force and chemical bond interaction, so it will affect the flow of water on the surface.

Horizontal wells with multiple fractures are becoming more prevalent in tight gas reservoir. However, it is uneasy to obtain the applicable deliverability formula of multiple-fractured horizontal wells using analytical method in consideration of multiple factors, such as the non-Darcy effect, interference between fractures, the coupling effect with reservoir, and formation heterogeneity. This project investigates the deliverability formula of multiple hydraulically fractured horizontal wells in tight gas reservoir using a special numerical method with a focus on the existence of non-Darcy effect and formation heterogeneity. Numerical model expected from daily production data, including wellhead pressure history and production history, is obtained using the numerical well test method, which has an advantage in considering reservoir heterogeneity and complex boundary. The effect of non-Darcy in gas well is discussed using rate dependent skin when constructing the numerical model. The parameters of the numerical model on multiple fractured horizontal well are validated compared with analysis of real pressure build-up well test data. Productivity well test is then simulated based on the previous numerical model, and binomial deliverability equation is obtained from simulated productivity well test curve. The error of absolutely flow rate which derives from the simulation results and modified isochronal test from the field is less than 6%. This paper provides a fast and reliable numerical tool to multifractured horizontal well performance prediction in tight gas reservoir, especially considering non-Darcy effect and reservoir heterogeneous.