Approximately 70% of the world’s remaining hydrocarbons are located in sand-prone reservoirs and current approaches to handle sand production are still facing many challenges. One aim of this work is to explore the use of polyacrylamide-based polymers in agglomerating formation sand and clays to improve the effectiveness of standalone sand screens. Polymer bridging interactions, charge neutralization and bare patch attraction are the three main agglomeration mechanisms being considered due to their capability of forming aggregates with superior shear resistivity and size. Preliminary results using Scanning Electron Microscopy (SEM) and Laser Particle Size Analysis (LPSA) have indicated a median growth in particle size of around 5 times when treated with cationic polyacrylamides only. Multi-polymer agglomeration systems were able to produce sand agglomerates of similar sizes but with much higher resistance to shear and more able to retain its structure upon drying. The novelty of this multi-polymer agglomeration system when coupled with sand screens is in the ability to potentially provide a very cost-effective means to solve sand production issues at the source, eliminating the need for costly remedial solutions at the topside and resin-based sand consolidation methods which impair reservoir permeability. Our work also investigate the effectiveness of particle filtration process, in particular using a fully-coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) approach involving poly-dispersed, adhesive solid particles. We found that an increase in particle adhesion reduces solid production through the opening of a wire-wrap type sand screen. Over time, as particle agglomerates continuously deposit on top of the sand screen, layer upon layer of particles is built on top of the screen, forming a particle pack. It is observed that with increasing particle adhesion, the pack height build up also increases and hence decreases the average particle volume fraction of the pack. This trend suggests higher porosity and looser packing of solid particles within the pack with increased adhesion. Furthermore, we find that the pressure drop for adhesive case is lower compared to non-adhesive case. Our results suggest agglomerating solid particles has beneficial effects on particle filtration. One important application of these findings is towards designing and optimizing sand control process for a hydrocarbon well with excessive sand production.

Sand agglomeration in oil & gas reservoirs: Chemistry, experiments and simulations

255th National Meeting (2018)

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