Utilizing Computational Fluid Dynamics (CFD) Analysis as a Design Tool in Frac-Packing Applications To Improve Erosion Life

Abstract

Abstract Frac packing tool erosion is becoming a growing concern as more high-profile deepwater wells are completed using this technique. Today many deepwater wells require frac pack pump rates of at least 40 barrels per minute (bbl/min) with proppant loads reaching 300,000 lbs. As zone lengths are increased and multi-zone operations are performed jobs requiring 60 bbl/min pump rates with proppant loads reaching 900,000 lbs. may be more typical. The current frac packing tool designs must be optimized to accommodate the higher pump rates and proppant volumes required to complete these deepwater wells. Computational fluid dynamics (CFD) analysis of these systems provides valuable insight to what is physically happening to the tools at these high pump rates and proppant loads. Analyzing various patterns, such as velocity, fluid path, erosion, and sand concentration at high rates helps identify critical areas within the system that require design optimization. CFD analysis is a cost effective alternative to trial-and-error testing, which can cost upwards of $150,000 per test and prolong the development phase. Two sizes of systems have been analyzed using CFD analysis and modified based on the results of that analysis. Full scale tests were also performed at 40 bbl/min on these two systems to compare the actual results with that of the CFD analysis. The CFD analysis was able to generate accurate profiles of the physical erosion patterns observed after the full scale tests were completed. Although CFD cannot accurately predict magnitudes for erosion rates, it can predict erosion profiles and velocity magnitudes. Research is currently ongoing to accurately predict erosion rate magnitudes. This paper will detail the development, analysis and qualification testing of a next-generation frac packing system capable of use in ultra-high-rate operations.