Can Sand-Screen Failures Be Prevented in Gravel-Packed Cased-Hole Completions?

Abstract

Abstract Sand control screens must effectively retain the gravel pack and formation sand, and provide a conduit for fluids to flow into a cased hole producing well. A failure may occur while completing the well, or at some time during the well's operating life. The root cause of the screen failure is often difficult to determine with absolute accuracy. Often, it is determined that screen failure occurs due to a combination of plugging and erosion resulting in the loss of sand control. A comprehensive test program was undertaken to evaluate erosion rates of different screen types of cased hole completions completed with wire wrap, prepacked screens, metal mesh, or compliant sand screens. The purpose was to determine whether any screen type had a marked advantage to resist erosion during the gravel packing process. Tests were conducted at high velocities to simulate the end of the gravel packing process to determine erosion of the screen in a reasonable time scale. To evaluate the expected screen's service life while the well is in production, configurations of each screen type were installed in a test fixture, and several tests were conducted at different velocities and sand concentrations. Special ports were used to simulate producing through a cased hole perforation tunnel. The sand was sized to pass through the screen with minimal plugging, which would simulate fines production over time in a producing well. The specific wear rates and percent of rate loss were determined for each test. Micro photos were used in the analysis of the wear patterns, along with pre and post test measurements of the wire wrap slots or metal mesh pore sizes. This paper will describe the test methods used, the test results and lessons learned, and will describe a model that can be used to predict a screen's service life for cased hole completions based on a given set of well conditions.