Natural Gas Hydrate Formation Prediction and Prevention Strategies in Gas Transmission and Processing
Natural Gas Utilization Workshop
One of the most critical flow assurance challenges during oil and gas exploration and production is hydrate formation, which can stop the flow and even totally block all production. HYSYS and ProMax are the major software using for hydrate formation prediction. This project is conducted by utilizing the software to predict gas hydrate formation conditions, and to develop hydrate formation strategies based on the simulation data.
The K-value method, Peng-Robison state of equation in HYSYS V8.6 and ProMax V3.2, and experimental method are applied for hydrate formation prediction in natural gas pipeline systems.
3.1 CO2/H2S fraction
The acidic gases (H2S, CO2) that are part of hydrate composition and can affect the hydrates formation conditions. We can see that higher concentration of CO2 in the gas stream can lower the hydrates forming temperature, while H2S will cause the opposite effect.
HYSYS and ProMax were used to predict Lavan-3 gas well and Salman wellhead hydrate formation conditions, and their prediction errors were under 5% compared with experimental data.
The methanol/Ethane glycol has been injected at 0% 10%, and 20% of weight at the aqueous phase. Then the hydrates formation temperature and pressure are simulated were compared with the field pipeline data and experimental data.
50MMSCFD of natural gas has been treated at TEG plant, at a circulation of 8 GPM of lean TEG. The water content in the gas stream has removed from 75.90 lbm H2O/MMSCF to 4.74 lbm H2O/MMSCF. The hydrates forming temperature has suppressed from 52.66 °F to 23.47 °F.
The formation of hydrate can cause significant losses in oil and gas production processing and transmission procedure. Results from HYSYS and ProMax were used here to predict wellhead or pipeline hydrate formation conditions, thermodynamic inhibitor injection rate, and TEG circulation rate.