Constitutive equation for fluid flowing through tight reservoirs

To realize efficient development of tight reservoirs, mechanics of fluids in tight reservoirs should be established. In order to establish it, constitutive equation for fluid flowing through tight reservoirs must be available first. Core flow test suggests that fluid flowing through tight reservoirs belongs to low-velocity nonlinear flow in porous media, and there exist many mathematical models which describe the constitutive relation of low-velocity nonlinear flow in porous media, so constitutive equation for fluid flowing through tight reservoirs should be selected properly among all. Compare frequently referenced Ruizhong Jiang's equation and Yanzhang Huang's equation with newly appeared Power-Quotient Equation among those mathematical models, discovering that: Power-Quotient Equationis global differentiable functional equation, which is simpler than two-piecewise differentiable functional equations such as Ruizhong Jiang's equation and Yanzhang Huang's equation; Power-Quotient Equation makes starting pressure gradient seem to exist but actually not, and reconciles two contrasting views about whether starting pressure gradient exist or not, then leads the research of fluid flowing through tight reservoirs will not intertwine in whether starting pressure gradient exist or not any more, however there exists controversial starting pressure gradient term in Ruizhong Jiang's equation and Yanzhang Huang's equation; Power-Quotient Equation first reveals that near-linear flow at medium velocities in porous media exists and describes it successfully according to the existent inflection point on a smooth curve of the data points from core flow test, while Ruizhong Jiang's equation and Yanzhang Huang's equation failed to describe the near-linear flow at medium velocities in porous media. Thus, Chengwei Qi's Power-Quotient Equation can be used as constitutive equation for fluid flowing through tight reservoirs.