Analyzing Corrosion Prediction and Dose Optimization of Corrosion Inhibitor in Oil Field Production

Abstract

Oil and gas field produced water disposal is very serious issue in hydrocarbon industry. Corrosion occurred by this produced water from oil industry is very difficult to be predicted. Produced water reinjection, treatment and disposal are a huge problem in onshore as well as offshore fields. As the reservoir depletes, mostly the water cut increases up to 90%, thus increasing the chances of corrosion of the surface and subsurface equipment. In this experimental work corrosion studies were undertaken on steel tubular at reservoir temperature. It is essential to remove the dissolved oxygen to control corrosion. The dissolved oxygen content in effluent was found to be high. The dose of sodium sulphite as oxygen scavenger after treatment of the injection water in the laboratory is optimized. Dissolved oxygen may vary from time to time; therefore the dose of oxygen scavenger may be changed accordingly for effective removal of oxygen. Sodium sulphide requires a catalyst like Cobaltous chloride. For dose optimization of corrosion inhibitor, laboratory treated effluent after filtration with 0.45-µ filter was used for this study. The water was treated with different concentrations of corrosion inhibitors (WIN). The rate of corrosion for different doses of corrosion inhibitor along with oxygen scavenger needs to be optimized. Corrosion plays a very important role in reducing the life of tubulars, Completion equipment, handling and treating equipment. Corrosion studies needs to be carried out in order to optimize the dose of oxygen scavenger and corrosion inhibitor. In this research work the corrosion studies were undertaken on N-80 steel tubular coupons at 88 °C. This paper discusses the laboratory fluid compatibility, scale and corrosion prediction analysis and treatment for injection water utilization while providing an insight into the potential impact of scale and corrosion risks associated with raw produced water.