Optimizing Sand Control Design Using Sand Screen Retention Testing

Abstract

Abstract Sand retention tests have been widely accepted as one of the methods of sizing screens for Stand Alone Screens (SAS) in open hole completions. The results of such tests are, however, highly dependent on the experimental conditions and prone to artefacts; small and apparently innocuous changes to the test conditions can cause wide variations in results1. Furthermore it may require several tests performed with different screen and test sands to adequately select the appropriate screen size that would prevent plugging and sand production. When done correctly sand retention tests have proven to be an optimum method for SAS sizing. Several mathematical models have also been developed for screen sizing using series of laboratory data but the applicability of these models to other reservoirs, different from the test reservoir, is questionable. This paper discusses screen selection for a highly non-uniform unconsolidated reservoir in a field in the Gulf of Guinea based on sand screen retention test using screen sizes pre-selected on Coberly's criterion. Coberly's criterion is extensively used in the industry for screen only design. It is however still subject to debate most especially with respect to sand control failure due to plugged screens, or catastrophic failures due to screen erosion. The optimization work goes further to compare the results of the screen retention test in the laboratory against published numerical models, by applying these models to the field in question. From the results, a detailed experimental workflow for sand control design and screen selection for unconsolidated reservoirs has been developed for the Region; this also includes the sand screen retention testing applicability and requirements for a successful design.