PetroChina Company Limited
Calculation method for dynamic fluid loss of acid-etched fracture considering wormhole propagation

Abstract:

The invention discloses a calculation method for dynamic fluid loss of acid-etched fracture considering wormhole propagation, which is applied to pad acid fracturing process, comprising the following steps: Step 1: dividing the construction time T of injecting acid fluid into artificial fracture into m time nodes at equal intervals, then the time step .DELTA..sub.t=T/m and t.sub.n=n.DELTA.t, where, n=0, 1, 2, 3, . . . , m, and to is the initial time; Step 2: calculating the fluid loss velocity v.sub.l(0) in the fracture at t.sub.0; Step 3: calculating the flowing pressure distribution P(n) in the fracture at t.sub.n; Step 4: calculating the width w.sub.a(n) of acid-etched fracture at t.sub.n; Step 5: calculating the wormhole propagation and the fluid loss velocity v.sub.l(n) at t.sub.n; Step 6: substituting the fluid loss velocity v.sub.l(n) into Step 3, and repeating Step 3 to Step 6 in turn until the end of acid fluid injection.