Occurrence of naphthenate deposition in crude oil production field offshore Niger Delta

Abstract

Crude oil and produced water samples obtained from ten wells in an offshore field, Niger Delta, were analyzed, in order to determine the occurrence of naphthenates deposition in the field. Total acid number (TAN) and °API of the crude oil samples, pH and metal ions concentrations of the produced water samples were determined. The results revealed that TAN values ranged from 0.47 to 1.01 mgKOH/g with pH of 6.9–8.9, which were above established threshold. The metal ions concentrations especially for Ca++ and Na+ were relatively high. These imply a high possibility of metal-naphthenate precipitation in the oil production facilities in this field.