Developing a Wax-Deposition Simulator Through Operator/Vendor Cooperation
Authors: Mueller J. Bryant , Wilkens R.J. , Wade Kevin 
Published: October 2008

The paper will discuss the cooperation between Baker Jardine & Associates ("BJA") and Shell International Exploration and Production, Inc. ("Shell") to develop a tool to simulate accurately wax deposition in flowlines. Shell have developed the technology to determine the rate of wax deposition in a flow system. Baker Jardine worked with Shell to incorporate this proprietary technology into BJA's commercial simulator PIPESIM.

The cooperation between the two companies demonstrates how the petroleum industry is now embracing alliances to improve technology. The wax deposition model that Shell developed is unique in the industry. By working with BJA to implement the model into a commercial simulator, the wax deposition technology becomes easily accessible to all Shell employees. By working with an outside company, Shell is able to improve its internal technology transfer. Thus, Shell's flow assurance efforts are more consistent and efficient.

Introduction

Flow assurance is a major issue for all operators in today's petroleum industry. There is continuing pressure to improve flow assurance solutions and to find answers at a faster rate. Shell identified the need to model the rate of wax deposition in flowlines in order to predict and mitigate wax deposits. Shell had already developed their own in-house wax-deposition model. However, they needed a user-friendly software implementation of this model in order to promote its usage among Shell staff. A key issue was the need to protect the proprietary nature of the model while still allowing future upgrades. After the implementation of the new version, it was important that the Shell Research team not become burdened with the task of providing user support for this new tool.

Shell worked with BJA to implement the wax-deposition model into the commercial multiphase flow simulator, PIPESIM. BJA and Shell have previously worked together on other projects and PIPESIM is a software package with which Shell's engineers are already familiar. The joint cooperation allowed Shell to maintain proprietary algorithms in a Shellcreated DLL while benefiting from a new graphical user interface (GUI) in a commercial package. The separate DLL protects the simulation method and allows for future upgrades to the model, without hampering the functionality of PIPESIM.

By combining internal research with commercially available simulation tools, Shell and Baker Jardine developed a tool that achieves all the stated objectives. This tool was developed in significantly less time than if Shell or Baker Jardine were to attempt to develop the tool on their own. Key elements to the success are the wax-deposition expertise of Shell, the commercial strength of BJA's PIPESIM, and true operator/vendor cooperation. This example of cooperation for the purpose of flow assurance has made for a synergistic solution.

Statement of Theory and Definitions

Wax-deposition occurs when paraffins crystallize on a cool pipe wall (Twall &lt; Tdeposition). The objective of waxdeposition modeling is to determine where and how fast the deposition is occurring.

Shell developed in-house software to predict wax deposition in well tubing, multiphase flowlines, and export lines. This model has been coded by Shell into a Dynamic Link Library (DLL).