Fluid Transport Characteristics And Engineering Methods In Tight Oil And Gas Fields

In traditional fluid mechanics,the velocity of the fluid at the wall is zero,which called no slip boundary condition.Under the condition of micro-nano scale,no slip boundary condition is no longer applicable due to the increase of solid-liquid interface force.In this paper,based on the experimental phenomena of flow in a micro quartz tube,the boundary model of the thickness of the wetting boundary viscous layer that changes withstress was estabilshed.Thereby,the flux formula of micro tube under the laminar flow condition was deduced and analyzed,and its flow characteristics under flowing micro-nano scale were analyzed,Than the experimental model of deionized water micron tube was used to valify the new theoretical model,which was applied to the dense porous media to duduce the seepapge model considering the effect of negative slip,and the model was analyzed step by step.And at the basis of flow experiments of deionizing water from the dense cores,the new model was verified.Which was applied to calculate its capacity in reservoir engineering,and the capacity and pressure distribution were analysed.Finally the single-phase nonlinear seepage model was extended to two-phase non-linear seepage flow,and the seepage flow model of two-phases in dense porous media was deduced,and the effects of permeability and viscosity ratio on the two-phase seepage in dense reservoir were analyzed by deionized water flow experiment in dense core.The results show that under wetting conditions,the thickness of the boundary viscous layer decreases with the increase of driving force;The newly established boundary model and flow formula that under the micro-nano scale are very consistent with the experimental results,the application of first-order flow model is more simple,when the pressure gradient is small,the index terms work and result in the effect of non-line flow;By comparing with the results obtained in the experiment o the dynamic oil saturation based on the nuclear magnetic resonance method,it can be found that the experimental data obtained are basically consistent.It can thus be concluded that when the permeability and the movable oil are reduced,the corresponding boundary adhesion layer is thickened.Even if the saturation is different,the thickness of the static boundary layer of oil-water is mostly similar,and the change of the viscosity ratio is the same as the thickness of the boundary adhesion layer,which has no obvious change.