Midstream gathering systems present several unique pipeline simulation modeling challenges. The first, and most significant challenge, is that systems are not static. In fact, systems are constantly changing as new wells are added and depleted. One method of handling this constant change is to use geographic information systems (GIS) to build models. This requires the simulation software to be capable of importing and exporting GIS data, fix topology errors on the fly, convert 2D GIS data to 3D using digital elevation models, and display the models over geo-referenced aerial backgrounds.
The second challenge is that gathering systems are often multiphase, enabling liquids and solids to collect in low spots or low velocity areas. In addition, gathering systems are often looped and interconnected. The combination of multiphase and multipath networks makes predicting flows and pressure drops difficult. In order to accurately portray how a system would react in the real world requires the simulation to be tuned often. Unfortunately, manually tuning a complex gathering system is practically unfeasible. Automatic tuning algorithms utilizing SCADA data to tune the model is likely the only reliable method to accomplish this task. This makes it possible to determine the location and severity of liquid holdup, hydrates, or salt buildup. In addition, simulation software can be used to debug new models by identifying incorrect geometry, equipment, or operational parameter model inputs.
The third challenge is analyzing and understanding the simulation results. This requires the application to have both the ability to create 2D or 3D color simulation maps and graphs for visual interpretation, as well as, export the results into spreadsheets for further analysis.
One of the primary purposes of computerized pipeline simulation is to assist midstream companies to troubleshoot existing systems and design modifications or new systems. The tools available to the industry today enable companies to analyze and make decisions quicker, more reliably and efficiently.