Abstract

Sand production is a major problem on weakly-consolidated fields. To limit the sand flow into the well, downhole filters are used. Filter sizing criteria, however, only work for a narrow range of rocks. Optimal sizing criterion suggests size of filter pores small enough not to let coarse particles to enter the well, but big enough so that skin-factor would not be too big. The aim of this article is to propose a method to create universal sizing criteria for any rock and filter type.

To model suspension flow through filter Discrete Element Method (DEM) was used. It suggests modeling system on the scale of single rock grains, which allows reconstructing all the microscopic mechanisms and interactions during filtration process. Particles were spherical, their sizes differed from 40 to 1400 μm. Interactions between particles were via Hertz forces. Different types of filters were considered: slotted liners (SL) and Gravel Packs (GP).

Based on the DEM models number of numerical experiments was carried out. Recomendations to sizing criterions and a method to evaluate Gravel Pack's skin-factor are proposed.

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