Abstract
Today, oil and gas fields gradually become mature with a high amount of water being produced (water cut (WC)), favoring conditions for gas hydrate formation up to the blockage of pipelines. The pressure drop is an important parameter which is closely related to the multiphase flow characteristics, risk of plugging and security of flowlines. This study developed a model based on flowloop experiments to predict the relative pressure drop in pipelines once hydrate is formed in high water cutsystems in the absence and presence of AA-LDHI and/or salt. In this model, the relative pressure drop during flow is a function of hydrate volume and hydrate agglomerate structure, represented by the volume fraction factor (Kv). This parameter is adjusted for each experiment between 1.00 and 2.74. The structure of the hydrate agglomerates can be predicted from the measured relative pressure drop as well as their impact on the flow, especially in case of a homogeneous suspension of hydrates in the flow.
Highlights
Gas hydrates are ice-like crystals composed of molecular water cages entrapping light hydrocarbons at low temperature and high pressure [1]
Several chemical strategies are applied to subsea flowlines, such as using thermodynamic inhibitors (THIs) or low dosage hydrate inhibitors (LDHIs), such as kinetic hydrate inhibitors (KHIs) or anti-agglomerants (AAs)
To save Operational Expenditure (OPEX) and Capital Expenditure (CAPEX), LDHIs are used in small amounts compared to those of THIs
Summary
Gas (clathrate) hydrates are ice-like crystals composed of molecular water cages entrapping light hydrocarbons (methane, ethane, propane, etc.) at low temperature and high pressure [1]. Several chemical strategies are applied to subsea flowlines, such as using thermodynamic inhibitors (THIs) or low dosage hydrate inhibitors (LDHIs), such as kinetic hydrate inhibitors (KHIs) or anti-agglomerants (AAs). The conventional technique to prevent gas hydrate formation is thermodynamic inhibition (e.g., using methanol or glycols) which shifts the hydrate equilibrium conditions to a higher pressure and lower temperature. To save Operational Expenditure (OPEX) and Capital Expenditure (CAPEX), LDHIs are used in small amounts compared to those of THIs. The role of KHIs is to delay the nucleation or growth of hydrate crystallization while AAs allow the hydrate formation but help to disperse hydrate particles finely in production fluids, in other words, preventing hydrate agglomeration and plugs. AAs are Energies 2020, 13, 686; doi:10.3390/en13030686 www.mdpi.com/journal/energies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
