Abstract

This study presents a comparative analysis on the performance of acid fluid systems, which are commonly used for high-temperature (>150°C) carbonate matrix stimulations. The comparison is based upon the key factors including ease of implementation, corrosion and operational costs, and performance assessment in terms of improving well deliverability. Moreover, core and field scale numerical simulations are performed to examine the rock matrix acidizing behavior under different reservoir conditions. The main variables are acid types, temperature, and injection rate. Results underline the conditions under which optimal stimulation concerning permeability and length of treatment is attainable.

According to results, a stand-alone stimulating fluid of glutamic acid diacetic acid (GLDA) shows the lowest corrosion rate followed by methanesulfonic acid (MSA) and hydroxyethyl ethylenediamine triacetic acid (HEDTA) under high temperature conditions. In the absence of corrosion inhibitor, GLDA gives the lowest results in terms of corrosion for 22Cr and 13Cr steels. Moreover, acid response data revealed that GLDA has the lowest optimum injection rate when compared to other acids considered in this study. Our simulation results show that the penetration depth (acid front) of acid is highly affected by the radial flow characteristics in field scale simulations, as the penetration depth is not linearly correlated to the volume of acid injected.

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