Measurement of Reduced Permeability at Fracture Face Due to Proppant Embedment and Depletion

Proppant embedment at the fracture face of a hydraulically fractured formation can result in reduced hydrocarbon flow from the matrix into the fracture due to reduced pore throat size, crushing of the rock, fines generation and pore plugging within the embedment zone (i.e. at the fracture face). Conventional proppant conductivity tests can only measure conductivity losses that occur within the proppant pack due to frac gel damage and compaction, not the damage at the fracture face. Test methods that can directly measure the effect of embedment on hydrocarbon production rates from a fracture are needed. A new test method that can measure proppant embedment at the fracture face as a function of different variables such as depletion, formation UCS and permeability, proppant type and loading has been developed. The same test method can also measure the resulting changes in the fracture-face permeability and the rate of fluid flow from the matrix into the fracture as a function of depletion, coupled with conductivity measurement within the proppant pack. A numerical model was built to provide reference solutions for the initial permeability.