Patent ID: 7774183

Claim:
A method of modeling the pressure in a wellbore during acid treatment with a self diverting acid delivered at a flowrate Q, the pressure being determined at a depth z, a distance r from the center of the well, and a time t, the method involving use of functions derived from core flooding experiments wherein a self diverting acid is injected into a core and the pressure along the core is measured as a function of time, the modeling method comprising: calculating at least one of an effective viscosity μ r , a mobility M r , and a permeability k r , wherein μ r = μ d ⁢ Δ ⁢ ⁢ p r Δ ⁢ ⁢ p o ⁢ Θ 0 Θ o - Θ r M r = k 0 μ d ⁢ Δ ⁢ ⁢ p r Δ ⁢ ⁢ p 0 ⁢ Θ 0 Θ 0 - Θ r and k r = k 0 μ d μ ⁢ Δ ⁢ ⁢ p r Δ ⁢ ⁢ p 0 ⁢ Θ 0 Θ 0 - Θ r wherein: k 0 is the initial absolute permeability of the core, before acid is injected; μ d is the viscosity of the displaced fluid originally saturating the core before acid is injected; μ is the viscosity of the acid; Δp r is the pressure drop derived from the core flooding experiments and is the pressure drop at the time t r that the pressure drop changes from a first linear trend to a second linear trend; ⊖ r is the number of pore volumes delivered to the core at the time t r ; Δp o is the pressure drop at t=o of the core flood experiment; and ⊖ o is the pore volume to breakthrough measured in the core flood experiment; and using a simulator to calculate pressures within the formation on the basis of the effective viscosity μ r , the mobility M r , and/or the permeability k r .