Stand-alone screens are often a simple and cost-effective sand control solution for long, multi-zone openhole completions. A recent technology advancement is a self-mitigating MazeFlo™ screen for enhanced sand screen reliability. Redundant screens and compartment mazes are incorporated to capture local sand ingress caused by screen damage without interrupting the overall well production. A common screen damage mechanism is screen erosion. The new screen extends the production capacity by increasing erosion resistance and providing self-mitigating functionality.
A self-mitigating screen includes an outer primary and an enclosed offset inner secondary screen. A maze compartment stands between the two screens to enable self-mitigation of screen damage. Without the primary screen damage, the secondary screen must withstand continuous fines production to maintain sand control capability in the well. If the primary screen is damaged, the erosive sand will enter the maze compartment and deposit on the secondary screen. The integrity of the maze compartment must be maintained until the compartment is fully packed and the well production is diverted to adjacent undamaged screens.
This paper discusses a methodology to evaluate the erosion resistance with regard to operating conditions in a self-mitigating screen. The methodology includes a suite of laboratory tests to establish an erosion baseline for a wire-wrapped screen. The erosion baseline, along with fluid flow modeling will provide design guidelines for a given operating condition. A proper MazeFlo screen design sustains the self-mitigation capability throughout the life of the well. The design envelope can be further expanded when combined with other technologies such as zonal isolation and inflow control devices.