Preliminary Results of a Satellite Image Frequency-Resonance Processing of the Gas Hydrate Location Area in the South China Sea

Abstract

The experimental studies with the frequency-resonance method of satellite images processing using were carried out on a local site in the South China Sea, studied by a 3D seismic survey and drilling, where gas hydrates were successfully extracted by Chinese oilmen. In the area of the drilled wells that opened the gas hydrates, the resonant frequencies of the gas hydrates were refined, with which further investigation was conducted. At the specified resonant frequency, two anomalous zones “Gas-hydrate-1” and “Gas-hydrate-2” were detected and mapped on the entire image area. These anomalies are located within the BSR zones, identified by 3D seismic data, and are significantly smaller in area. At resonance frequencies of gas, four anomalous zones of the “gas reservoir” type have been mapped over the entire area of the image: Gas-1, Gas-2, Gas-3 and Gas-4. Within all these anomalies the reservoir pressure intervals were estimated: (1) 19.8–21.0 MPa; (2) 21.0–21.5 MPa; (3) 21.0–21.5 MPa; (4) 21.2–21.5 MPa. In the contours of “Gas-hydrate-1” and “Gas-hydrate-2” anomalies, anomalous responses at the resonance frequencies of gas were not fixed. It can be concluded that there are no sub-hydrate deposits of gas here. Within the surveyed area, anomalous zones at resonant frequencies of oil were not detected. In the Gas-2 anomaly contour a channel for deep fluids vertical migration was revealed and localized—a small local area with very high reservoir pressure values of 67 MPa. There are good reasons to state that the obtained results are a significant addition to the data of earlier studies on this local site.