Sodium Gluconate as a New Environmentally Friendly Iron-Control Agent for Acidizing

Topics: Corrosion
Fig. 2: Iron concentration in the samples collected while neutralizing 5 and 10 wt% HCl loaded with 5,000 and 10,000 ppm iron (III), respectively, in the presence and the absence of 1:1 molar ratio of sodium gluconate.

Iron precipitation is a serious problem in acidizing treatments, causing formation permeability damage by restricting flow channels. Solutions have included buffers, reducing agents, and chelating agents. Experience has shown that chelating agents are the most effective; however, limitations of current chelating agents include poor stability at elevated temperatures, higher cost, low solubility in acidic medium, tendency to precipitate calcium products, and negative health and environmental effects. This work introduces sodium gluconate as an efficient and environmentally friendly iron-chelating agent.

Introduction

Corrosion is a major challenge in any acidizing treatment. The scale of such a problem depends on the acid type; acid concentration; temperature; and the presence of corrosion inhibitor, intensifier, or undesirable corrosion accelerator. In cases where hydrochloric acid (HCl) is used, the effect of the corrosion is magnified and can hinder the success of the treatment, especially at elevated temperatures and higher acid concentrations. Acid corrosion not only destroys storage and mixing tanks, piping, fittings, coiled tubing, and wellbore tubing, but the corrosion products are also carried out with the acid flow and enter the formation. When the acid is in a live condition, these corrosion products are readily soluble. However, when the acid reacts with the formation and the pH increases, the corrosion products show a high tendency to precipitate and plug the pores.

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 172640, “Sodium Gluconate as a New Environmentally Friendly Iron-Controlling Agent for HP/HT Acidizing Treatments,” by Ahmed I. Rabie, SPE, andHisham A. Nasr El-Din, SPE, Texas A&M University, prepared for the 2015 SPE Middle East Oil & Gas Show and Conference, Manama, Bahrain, 8–11 March. The paper has not been peer reviewed.
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Sodium Gluconate as a New Environmentally Friendly Iron-Control Agent for Acidizing

01 September 2015

Volume: 67 | Issue: 9

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