Details

Autor(en) / Beteiligte

• Bandara, K. M. A. S.
• Ranjith, P. G.
• Zheng, W.
• Tannant, D. D.
• De Silva, V. R. S.
• Rathnaweera, T. D.

Titel

Grain-scale analysis of proppant crushing and embedment using calibrated discrete element models

Ist Teil von

• Acta geotechnica, 2022-11, Vol.17 (11), p.4837-4864

Ort / Verlag

Berlin/Heidelberg: Springer Berlin Heidelberg

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Proppant crushing and embedment in hydraulically-induced fractures is a major drawback to the recovery of unconventional oil/gas and geothermal energy production. This study provides a grain-scale analysis of the fracture evolution mechanisms of proppant crushing, rock fracture damage during proppant embedment, the influence of realistic reservoir/fracture fluid on proppant embedment, and the behaviour of proppant packs subjected to in-situ stresses using a discrete element modelling (DEM) approach. The results of this study reveal that the selection of an appropriate proppant type based on the nature of the reservoir formation plays a vital part in quantifying the degree of proppant crushing and embedment within fractures. The utilisation of frac-sand proppants instead of ceramic proppants in shallow soft sedimentary-based siltstone formations reduces proppant embedment up to 88%. However, whatever the depth of the fracture, the injection of ceramic proppants into granite-based geothermal formations is preferred to that of frac-sand proppants due to their lower proppant embedment and greater crush resistance. DEM analysis detected rock-spalling during the proppant embedment process, which ultimately led to the initiation of tensile-dominant secondary fractures in rocks. Fracture initiation, propagation, and coalescence during proppant crushing are analysed using calibrated DEM proppant-rock assemblies. Importantly, this study reveals that the saturation of formation rocks with fracturing/reservoir fluids may cause a significant increase in proppant embedment. Furthermore, proppant crushing, embedment, and re-arrangement mechanisms in proppant packs with different proppant distributions are analysed in this comprehensive numerical study.