Understanding Crude Properties to Optimize Corrosion Inhibitor Selection and Usage

Abstract

Abstract Banyu Urip Field is located in Central-East Java, Indonesia where well production fluids are routed from wellheads to processing facilities via interconnected full well stream piping and flowlines. The produced fluids contains high level of CO2 (45% mol) and H2S (1.5% mol). The utilization of carbon steel in the design of piping and equipment makes them susceptible to corrosion. Injection of corrosion inhibitor (CI) is recommended to minimize material degradation, and correct selection of CI is key to ensure corrosion management is effective and efficient. A comprehensive understanding of produced fluid properties is important prior to CI selection. Various experiments were conducted in high pressure-high temperature Hastelloy autoclaves to simulate process conditions, with support from proprietary company software modeling 7%, 20% and 80% water partitioning in Banyu Urip Oil samples. An oil-water wettability study was also a key factor to predict the threshold water cut at which produced water separates from crude oil and wets the metal surface of the flowlines. The experiments revealed potential corrosion rates that could be expected in Banyu Urip flowlines for a range of production scenarios. Results also demonstrated that a decrease in liquid shear stress yields a decrease in corrosion rate; where as a decrease in temperature yields an increase in corrosion rate due to reduction of FeCO3 scale protection. This FeCO3 scale protection provides self-inhibiting properties which are keys to selection and optimization of CI. Through the oil-water wettability study we can determine an optimal time where the metal surface is wetted by water and thus requires CI to control corrosion. This will help in determining the most cost effective corrosion management programs for the facilities. This paper will provide an overview of the Banyu Urip corrosion inhibitor selection process; describe the corrosion experiments conducted to verify the crude properties and the oil-water wettability studies to optimize the injection of CI.