Cognitive model-based system of optimal control of methanol supply to the flowline

The main problem during natural gas extraction is the hydrating risk. Hydrates could be formed at every exctraction stage: from gas foundation to the Central Processing Facility (CPF). The operation conditions could hardly ever be performed without hydrates because these conditions depend on many factors. Hydrating is quite an undesirable process because it decreases the field operations efficiency and causes accidents. The process operating procedure of any production field provides some measures to prevent hydrating. Mostly, hydrate growth inhibitors are supplied to the gas flow, for example, methanol. At this time the most important problem is evaluation for the current conditions optimal methanol flow rate or the water-methanol solution concentration. The system of optimal control of methanol supply to the gas flowline is offered in the article. It is based on real time analysis of head temperature and pressure, temperature and pressure in the entrance of the CPF and the ambient temperature. At this case current parameters and their dynamic are analyzed. The hydrating conditions are diagnosed with the algorithm offered in this article. The hydrate conditions are diagnosed with the algorithm offered in the article. This algorithm includes the results of temperature and pressure dynamic analysis and the cognitive model based on expert knowledge. This system was tested in the Yamburg gas condensate field. These tests confirmed real methanol saving.