Hydrodynamic Simulation Supports Scale Formation in Technical Specification for Downhole Equipment

Abstract

Abstract The huge carbonate reservoirs of the Brazilian pre-salt layer are likely to experience inorganic scale formation, mainly due to calcium carbonate. Emerging wellbore configurations, designed to reduce cost and increase reliability, show some drawbacks as the inability of injecting chemical inhibitors in the open-hole full-electric intelligent completion schemes. Traditionally, scale prediction relies on thermodynamic modeling, having a glimpse on the precipitation potential under static conditions, but neglecting the constructive details of the tools’ geometry and the fluid dynamic influence over the precipitated crystals. This paper details a Euler-Lagrange approach for the modeling of the liquid-solid flow applied to the simulation of scale formation in Internal Control Valves (ICVs). Numerical simulation is performed by the means of the Finite Volume method coupled to the Discrete Element Method (CFD-DEM), obtaining results as the accumulated mass in specific parts of the equipment (fouling hotspots) and the transient pressure uptrend as a consequence of flow blockage. The fouling forms as the particulate agglomerates adhere to the walls under the effects of turbulence and the adhesion force set up between particle-particle and particle-wall, hindering the flow due to the four-way-coupling between phases. Thus, the results compute the solids deposition that depends on the valve geometry, rather just the precipitation rate. Additionally, the simulation may be run by the Finite Volume Method coupled to the Discrete Phase Method (CFD-DPM) with an associated operation of remeshing. The fouling consists in computing the accumulated mass over the equipment surface and deforming the geometry to represent the obstruction. The numerical results are useful for the equipment technical specification, specifying the level of scale the valve has to withstand in a time window and also quantify acceptance criteria in terms of the pressure increase and the adhered mass. It is also possible to compare concurrent geometries in terms of reliability and propose design upgrades.