Document Type : Research Paper

Authors

• Rana A. Azeez ¹
• Najem Alrubaiey ²
• Mohamed Gazi ²

¹ Oil Engineering Dept, University of Technology-Iraq, Alsina’a Street, 10066 Baghdad, Iraq

² Oil Engineering Dept, University of Technology-Iraq, Alsina’a Street, 10066 Baghdad, Iraq.

Abstract

Drilling fluids can be considered complex liquids containing several desired materials. These materials (small additives) are specialty products that serve a specific need, such as controlling the rheological properties of the drilling fluid and reducing corrosion for operational drilling of both oil and gas wells. Additives used to resist corrosion are called corrosion inhibitors. Previous research has shown that polymers such as Carboxymethyl Cellulose (CMC) have high characteristics of corrosion inhabitation in an aggressive environment.  In this study, the effect of adding two samples of additives, CMC and Barite, on the corrosion of carbon steel in Iraqi bentonite water base mud solution has been evaluated using the weight loss technique. The study focuses on determining and comparing the corrosion characteristics of these mud additives. All the experiments were carried out in static flow and at room temperature.  Results show that CMC works as a good inhibitor when added to bentonite/barite mud. The calculated corrosion rates of 0.95mpy, 0.75mpy, 0.53mpy, 0.49mpy were found for bentonite mud, bentonite/barite mud, bentonite/CMC mud, and bentonite/CMC/barite mud, respectively. This would result in an inhibitor efficiency of about 50%.

Graphical Abstract

Highlights

• Adding additives important to regulate the rheological properties of drilling fluid. 
• Substantial changes in the plastic viscosity, density, yield point, and gel strength are distinguished to link to changes in the concentration of the additive.  
• Carboxymethyl Cellulose is a good inhibitor for mild carbon steel corrosion, especially in low concentrations in water base bentonite mud.
• Barite has little effect as a corrosion inhibitor on mild carbon steel corrosion in water base bentonite mud.

Keywords

• Barite
• CMC
• corrosion
• Mud
• inhibitors
• Rheological