Experimental Study of Effects of Water-in-Oil Emulsions Flow on Wax Deposition in Subsea Pipelines

Abstract

AbstractExperiments were performed to simulate the wax deposition in the flow of water in crude oil emulsions in subsea pipelines using a flow facility. Two water in crude-oil emulsions (Samples A & B) synthesize from two crude oil samples and their respective formation water from Orogbo and Okpohuru flow stations in the Southern Nigeria were used in the study. In the later period of wax deposition the combined effects of molecular diffusion and shear removal overwhelm the trapped water globules effect which dominates the wax deposition initially. The emulsions pour points increase from 30 to 41°C and the viscosities at 26 oC from 40 to 142 mPas, when the basic sediments and water of the crude samples increase from 10 to 40 °C. Addition of 250 ppm of Basorol E2032 (demulsifier) to the mixture of crude oil emulsion and 450ppm of long chain acrylate ester co-polymer (pour point depressant) was able to reduce the dimensionless wax thickness by 21.4 and 8.7% for crude oil samples A & B respectively. Addition of the demulsifier to the mixture of the emulsified oil and the pour point depressant enables the emulsified crude oil to be separated into its separate compositions of crude oil and water thereby making the stratified water-crude oil liquid flow to characterize the fluid flow in the pipeline leading to reduction in wax deposition.