This paper summarizes lab data showing that the pressure drop within the propped fracture is often 10 to 20 times higher than predicted using Darcy’s Law. The authors show that fracture conductivity is often dominated by non-Darcy effects, and that productivity improvements are controlled by the achievable fracture conductivities. Multiphase testing was used to examine the implications on gel cleanup and proppant flowback. During cleanup, the pressure gradients within the fracture may be increased 5-fold, substantially increasing the potential for proppant back production, as observed by the author in the field.
The proppant cell used in the lab was a tube 36” long by 1” diameter, but results agree with more traditional planar models used in other facilities.
Author(s): J.P. Martins, BP Exploration; D. Milton-Tayler, BP Research; H.K. Leung, BP Exploration
Paper Number: SPE 20709