Mobilization of Clayey Fines by Different Water Salinity Values in the Presence of Aluminium Oxide Nanoparticles

Abstract Water salinity is one primary factor that triggers migration of clayey fines in hydrocarbon reservoirs. However, the presence of some agents in the formation can delay this process and Aluminum oxide nanoparticles (Al2O3NP) have been proposed as one of such agents that can control fines migration. The primary objective of this study therefore is to experimentally determine the amount of fines free water effluent (in terms of pore volume) that can be produced from sand packs containing Al2O3 nanoparticles at different levels of water salinity. Another objective is to investigate the optimum sand treatment duration with Al2O3NP in control of fines migration. The sand samples contained 5% clayey fines obtained from the Niger Delta and a constant flow rate of 3ml/min was maintained for all the experiments which were conducted under standard condition. The amount of Al2O3 nanoparticles used in the samples was 20% of the clay content, but Al2O3 NPs were not used in all the reference experiments. Two different sets of experiment were conducted in this work; the first set of experiment involved flowing various salinity levels of water ranging from 0 – 40g/l through sand packs while the second involved soaking sand in brine for various numbers of days before flowing brine of 5g/l salinity through the sand. The experimental results showed that Al2O3 nanoparticles have the capacity to control clay mobilization in sands triggered by low water salinity. For the use of light crude at a salinity of 15g/l and 30g/l, about 25pore volumes and 33pore volumes of fines free effluents were produced respectively from the sand samples containing Al2O3 nanoparticles while about 13pore volumes and 21pore volumes of clean effluents were produced for the reference experiments respectively for a bulk volume of sand of about 55cm3. For the use of medium crude at a salinity of 15g/l and 30g/l, about 23pore volumes and 32pore volumes of fines free effluents were produced respectively from the sand samples containing Al2O3 nanoparticles while about 8pore volumes and 13pore volumes of clean effluents were produced for the reference experiments respectively. A comparison of the results of the sand samples containing Al2O3 nanoparticles with the reference results shows that the presence of Al2O3 nanoparticles in sands can control clay mobilization triggered by low water salinity. The results from the second part of the work showed that the maximum volume of clean effluent was recovered on the zero day of soaking. This implies that soaking is not required to achieve effective fines trapping in sand since the performance of fines trapping by Al2O3 NP diminishes with time.