Gravel Packing Horizontal Wells in Reservoir Oil Flow Equalization Projects

Abstract

AbstractRecent studies show that the flow along a horizontal well is not uniform or symmetrically distributed, as a larger volume of fluid enters the well near the heel. Flow equalization in horizontal wells is a state of the art strategy for assuring effective reservoir drainage and delaying the arrival of water breakthroughs. The idea is to provide a variable distribution of area open to flow along the horizontal section. The technique is applicable for several situations and is even more attractive in long horizontal section wells in heavy oil fields where friction losses in the well bore play an important role.The concept of flow equalization has been successfully applied in onshore (slotted liners) and offshore (carbonate reservoirs) applications in Brazil. The next and most challenging step is to place gravel packs in wells where premium screens with non-uniform perforation distributions were made in the base pipe. The main issue is the excessive friction losses generated by the restricted cross flow near the heel of the well when the gravel is placed, which may generate pressures that overcome the usually low frac pressures in deepwater environments.This article presents a case study for screen and gravel packing design for a typical deepwater application. Different screen base pipe perforation profiles are suggested and the gravel packing placement pressure was simulated. The strategy for optimizing flow equalization profiles with gravel packing pressures inside the operational window is defined by using an in house mechanistic model developed for OHGP operations.The model was modified for this specific application, considering flow divergence during gravel placement and friction losses throughout the perforations. Results indicate that it is feasible to gravel packing screens in such scenarios and achieve attractive flow equalization results. It is important to highlight that this approach will make possible to promote an effective sand exclusion and to improve the reservoir drainage at the same time,.