Enhancing the Penetration Depth of Stimulating Fluids in Carbonate Reservoirs Using Nickel Nanoparticles

Abstract

Generally carbonate acidizing job is carried out using HCl based stimulation fluids because of its effectiveness to dissolve and/or to disperse materials obstructing flow. But this effectiveness also creates a major drawback of its use; that is only surface dissolution and low penetration due to fast rate of reaction with carbonates. One method to overcome this problem is to mix appropriate organic acid with HCl but the reactions between organic acids and carbonates is less understood than those of HCl with carbonate rocks because of the presence of CO₂ and the precipitated reaction products; the organic salts of calcium and magnesium. Therefore much testing is needed to know the right organic acid to be mixed with HCl for a particular reservoir. Also they normally do not react to their full acid strength because of the release of CO₂ from carbonate dissolution and the cost of organic acid is significantly higher than that of HCl for equivalent mass of rock dissolved. In this paper I propose a new method to overcome these tribulations. In this method, Nickel nanoparticles mixed with water are injected into the formation before injecting stimulating fluid. Afterwards when the HCl based stimulating fluid is injected into the formation, it reacts with the Carbonates and produce CO₂. As soon as CO₂ is formed, Nickel Nanoparticles converts gaseous CO₂ into carbonic acid (aqueous CO₂). What nickel nanoparticles do is that it accelerates the natural conversion of CO₂ to carbonic acid. Use of nanoparticles reduces the amount of CO₂ by converting it into Carbonic acid (enhancing the stimulation job), reducing the cost and facilitating the reaction between organic acid and carbonate rocks.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015