The Assessment System Of Reservoir Engineering On5-spot Well Pattern In Low Permeability Reservoir

In this paper, pore flow mechanics in low permeability is studied for dealing with issuesin the theoretical research and practical field, which is derived from classical theory of flowin porous media. This dissertation takes5-spot well pattern for example to establish anassessment system of low permeability reservoir engineering, based on the ideology ofmoving boundary and streamline. The main tasks in this work include the following:(1) Single source issue. The concept of threshold pressure gradient (TPG) is detailedlyanalysed, which gives the significance in practical flow process. Meanwhile, the analysis ofmoving boundary is presented in unsteady state flow with TPG.(2) Pressure superposition principle. Because of the influence of threshold pressure gradient,the pressure differential equation possesses a non-homogeneity term, which contributes to theinvalidation of classical superposition principle. The exact pressure expression is derivedfrom differential equation with multi-wells and non-homogeneity term.(3) Effective driving pressure system. When coming to steady state flow phase, the time,final well pressure and oil production could be gotten from the multi-wells pressureformation changing with the variation of time and space, which determine the maximal wellspacing.(4) Production rate and effective development coefficient. Production expression is derivedfrom pressure formation of well pattern. Effective development coefficient is given by thestream function with TPG. The calculation results from the flow character, well patternsgeometry and pressure difference, but the variation scope of these results is different whensome parameter varies.(5) Two phase flow with TPG in two dimensions. The fractal flow curve is the function withregard to saturation and velocity. The research on water flooding in well pattern could bedone through combining streamline coordinate and characteristic line theory.