One of the major determinants for flow assurance of crude oil is its constitution and involves successful management of solid deposits. Major challenges in flow assurance are adequate selection of production equipment and pipelines. Control of wax deposition and its challenge can be met with better prediction through wax modeling. Precipitation of paraffin out of supersaturated crude oil mixture is responsible for wax deposits in pipelines. The authors have seen severe wax deposition in some of the Indian oil fields leading to the choking of pipelines and costing large amount of money and efforts in revival of these pipelines or replacement. This paper brings out application of wax deposition models and its field validation through studies carried out for some Indian oil fields. The studies have given insight into this complex phenomena and improved understanding has led to better wax deposition management in the pipelines. The main objective of this study is to predict the rate at which wax deposition takes place with respect to dynamic simulation model with field data of two different fields. The first case hasan8 in and 25 km long pipeline with burial depth of 1.2 m and multiphase transportation in the pipeline. The flow rate is about 500 m3/d of oil emulsion from A to B GGS. The temperature and concentration distribution of wax deposition rate has been analyzed through wax deposition models. The second case describes a pipeline of 8 in and 15 km long, burial depth 1.2 m, insulated with polyurethane of 2.5 mm thickness. To find out most suitable model for wax deposition, comparison between various WAX deposition models viz., RRR (Rygg, Rydahl and Ronningsen), Matzain and University of Michiganto available SCADA system has been made for better understanding, especially in context of Indian oil fields. The fluid properties for these fields were measured and the same have been used in wax deposition models for prediction of temperature drop, pressure drop and wax thickness calculations. Currently, in field operations to control the wax deposition, pigging is being carried out every month. Based on the studies carried out, pigging frequency has been optimized. Further, through improved understanding, the chemical injection could be optimized thus saving the cost in the field operations. Through wax deposition modeling and operational experience of two different fields, some insight to understand wax deposition phenomena with respect to molecular diffusion, shear dispersion and other mechanisms has been made. Through Matlab program for Matzain and Singh model, the predictions and field data has been compared for validation of results. It has been seen that for prediction of temperature profile along the trunkline, RRR model used in OLGA has been found most suitable and for accurate prediction of wax deposition; Singh model has been found to be more accurate for these fields. This study was taken up to improve the fundamental understanding of problems related to production and transportation of crude oil containing wax. Keywords: Wax deposition modeling, RRR model, OLGA, wax appearance temperature (WAT), Matzain model, University of Michigan/Singh modelCite this Article Anand Gupta, Anirbid Sircar. Wax Deposition Modeling and Comparison with Field Data for Some Indian Oil Fields. Recent Trends in Fluid Mechanics. 2017; 4(1): 1–15p.
