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Sand production is a common phenomenon in oil and gas reservoirs, which occurs when reservoir fluids exert a sufficient drag force on reservoir rocks to erode the matrix. Numerical models for sand production have been used to understand the sanding mechanisms and forecast sand-production potential of formations to design well completion, optimize production, and prevent setbacks in future operations. This paper presents a mathematical model for defining the conditions of sanding onset as well as to predict and quantify the sand rate. We also introduce fluid-flow coupling and a geomechanical and sand-production model. By using the proposed model and a set of experimental data, sanding-related variables are analyzed, and a matching process for the simulated results and forecast analysis are performed. The results show that elastoplastic constitutive models are indispensable, and a clear relationship exists between the sanding and plastic strains.

Abstract Among others factors, the triggers for sanding include: drilling, cementing, and completion operations; stress and pressure conditions; formation strength and weakening; and cyclic processes. Any single factor may suffice to initiate sand production. Hence, comprehending sanding entails examining various physical mechanisms concerning the interaction between fluids and rocks under reservoir conditions. This article presents an innovative study focused on evaluating and understanding the effect on sanding for the following components: vertical to hotizontal stress anisotropy, stresses around the hole, and formation strength and weakening. It combines three points in the analysis: (1) The 3D printing technology, which allows obtaining similar samples with high repeatability, giving reliability to the results; (2) A comprehensive program for the mechanical characterization of printed samples; and, (3) The study of the mechanical behavior of the samples under sanding conditions. The testing program includes uniaxial compressive strength (UCS), triaxial stress test, thick-walled cylinder and big hollow cylinder test with Sanding (BHCT) tests, which aims to show the relationship between the mechanical behavior, the test conditions, and the sand production level. The sample’s characterization reveals a high porosity, the presence of bedding planes, and similar Young’s modulus and UCS strength. For the BHCT tests, a novel equipment is introduced. This equipment uses large samples and enables: an independent control of axial stress, radial stress, pore pressure, and flow rate; and measurement of produced sand. The results show higher levels of sanding when the axial stress is low compared to the radial external stress.