Introducing a Novel MEG/EtOH Mixture to Improve Gas Hydrate Blockages Removal During Offshore Oil and Gas Production

Abstract

Offshore oil and gas production may present gas hydrate formation problems. Using thermodynamic hydrate inhibitors as methanol, mono ethylene glycol, (MEG), and ethanol among others to deal with these issues is frequent. The inhibition process initially consists of pumping thousands of barrels from topside to seabed in order to be injected into the reservoir or into the flowlines where the hydrates may form. Research has shown the difference between injecting MEG or Methanol. Methanol has a better performance dissolving hydrates and MEG can be cleaned and used again. A disadvantage for methanol is that part of it goes to the gas phase where is not useful for hydrate inhibition. Recently there has been proposed the possibility to mix them in order to increase their individual performance, which has been proved as satisfactory to both hydrate dissolving, and injection operation. In this study, the characteristics of current inhibition treatments and a new mixture of Ethanol and MEG were used to simulate the efficiency of the process to pump them from topside to seabed. To compare the mixture performance as a new hydrate inhibitor with the other THI treatments, data from real scenarios were used. The results can be used on the selection process for the THI pumping system, in order to optimize the needs of the gas hydrate inhibition system, in terms of power and storage on the platform.