Optimization Strategies of Production Parameters to Prevent Hydrate Reformation in Marine Gas Hydrate Production System

In recent decades, the development of natural gas hydrates has become a research hotspot of scholars all over the world. However, the decomposed gas and water in marine gas hydrate production system may regenerate gas hydrates due to the low-temperature and high-pressure environment in seafloor. In this study, a transient temperature and pressure calculating model was established to predict the risk of hydrate reformation in production pipelines during offshore natural gas hydrate development. Using the proposed model, the region of hydrate reformation in gas hydrate production wells were predicted quantitatively. Meanwhile, the hydrate reformation management strategies through optimization of production design parameters in combination with hydrate inhibitor injection were proposed and discussed in detail. The results indicate that the risk of hydrate reformation is the highest in the drainage pipeline (DP); however, the flow in gas-water mixed transportation and gas production pipelines (MTP and GPP) basically does not satisfy the hydrate formation condition. In the process of production well design, adding additional the EH and ESP can fully eliminate the hydrate reformation risk in the DP without using the hydrate inhibitor.

In-situ marine gas hydrate production methane leaks electrical monitoring system

In the process of gas hydrate exploitation, methane leakage needs to be monitored in real time, so an in-situ electrical monitoring system for methane leakage is designed. The monitoring system is mainly composed of monitoring cable, acquisition station, power module and general control platform. According to the electrical principle, the system carries out regional monitoring on the seabed formation, forms the resistivity map, and realizes methane leakage monitoring. The cost of the monitoring system is low, and it can be remotely controlled or automatically collected data according to the preset program, so the system has good application and research value.

Do marine gas hydrate deposits create heat flow anomalies on the seabed?

The aim of Stage 1 of the FNI project GEOHydrate is to prove the hypothesis that gas hydrates deposits (GHDs) create measurable temperature and heat flow (T&HF) anomalies on the seafloor. We use a PetroMod™ model for 98 Ma basin analysis of the Western Black Sea basin, developed in GEOMAR, FRG. The model was run 2 times – with and without GH formation. The resultant difference of the heat flows on the seabed shows average heat flow anomaly above GHDs of 7 mW/m2 and a maximum of 15 mW/m2.