Flow Assurance Management: innovative methodologies for Oil and Gas production optimization

This doctorate thesis reports the result of the research activities performed on issues concerning the transport of hydrocarbons in pipeline. These issues come under the so called "Flow Assurance", discipline aiming to assure the transport of hydrocarbons during the whole life of the well. The thesis is divided according with three main phenomena: the liquid loading in pipelines transporting natural gas; the ductile fracture in pipelines transporting gas at high pressure; the wax deposition in pipelines transporting waxy-oil. A new technique, based on surfactant injection, for the removal of the accumulated liquid in pipeline is investigated. This technique is analyzed through a wide number of experimental tests, with the goal to increase the deliquification success rate. It is presented a code for the calculation of the expansion wave velocity in natural gas mixture. The expansion wave velocity is part of a multi-physic model used for the control of the ductile fracture in pipeline. The obtained results are compared with experimental measurements and other predictions found in literature. A detailed analysis of the wax deposition in the pipeline is presented. Four production scenarios were simulated using different thermo-hydraulic and ther- modynamic software. The aim of the analysis is to evaluate the predictive capabilities of these software and to identify the most relevant wax deposition parameters to adjust to match the real field data, both in the single-phase and multi-phase ?