Determination of dynamic reserves of fractured horizontal wells in tight oil reservoirs by multi-region material balance method

To overcome the deficiencies of the material balance method, according to strong heterogeneity of tight oil reservoirs, the flow region of fractured horizontal well is divided into high permeable zone and low permeable zone, which are equivalent to radial composite percolation model. Based on parallel plane theory, multiple media of each zone are equivalent as a continuous medium, and with the integral method, the multi-region material balance to calculate the dynamic reserves for the fractured horizontal well of tight oil reservoirs is proposed base on the nonlinear seepage mechanism of tight oil reservoirs, and the corresponding pressure distribution equation and material balance equation for the two zones have been established. In view of the actual production performance, this method considers the pressure mutation and fluid exchange at the interface of two zones. The computational results of an example show that this method can work out the dynamic reserves within a single well control, the dynamic reserves of high permeable zone and low permeable zone, and the recharge rate from the low permeable zone to the high permeable zone in different production time accurately, which provides a basis for selection of well production and appropriate working system, and deployment and adjustment of development well pattern.