When fracturing zones having high permeability there is concern of damage to the matrix due to deeply penetrating fluid leakoff along the fracture and/or due to materials in the fluid that minimize the amount of leakoff. Materials used to minimize leakoff also have the potential to damage the proppant pack conductivity.

Previous tests have shown that high shear rates at the tip of the fracture may prevent the formation of external filter cakes, increasing the magnitude of spurt losses in highly permeable formations. This paper provides laboratory data on materials used to control spurt loss of linear gels [HEC], viscoelastic surfactant fluid and crosslinked borate-guars in formations having up to 500 md permeability. The depth of penetration into the matrix and magnitude of the permeability reduction to the matrix and proppant conductivity is shown.

This data is then used in a finite fracture conductivity production simulator that includes simulation of fracture face damage. Simulations are made for various fluid-loss additives controlling leakoff with different fracturing fluids over a range of formation permeabilities as well as other reservoir conditions and production modes. The simulations show the production effects of limiting the fluid loss penetration at the expense of permeability reduction in the formation and the propped fracture.

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