Wax Removal Procedure Used in Pre-Salt Oil Well

Abstract

This paper presents a real case of wax deposition in production lines from one Brazil Pre-salt well located at Santos Basin. It also shows a diagnosis of the problem as well as the methods adopted to remove the wax. An effective wax removal method may imply great costs, not only to implement it but also regarding the production loss involved. The best solution may not always be the one that removes the greatest amount of wax, but the one that implicates lower costs and allows operational continuity. In order to remove wax from production line, the first method used was pig launching. The second was diesel soaking and the third and final method used was a high velocity viscous flow inducing shear tensions to the walls. The result of each method allowed us to choose the best one regarding: production continuity, cost and wax removal effectiveness. It was possible to identify that the approach of pig launching was not effective enough. The diesel soaking approach had better result than the pigging, but generated higher costs due to the great length of the production line (9 km). The high velocity viscous flow method was the approach that gave the best results, concerning not only the amount of wax removed but also the reduced "closed well time" and costs. Repeating the high velocity viscous flow approach allowed us to optimize operation total time and the diesel consumption to perform it. The greatest conclusion was to find a method to prevent complete blockage of the production line without wasting long time of well production. Once this was the first well from Santos Pre-salt to present wax deposition issues, this paper is an important report of good practice in dealing with such a problem.