An overview of the gas hydrate petroleum system in offshore SW Taiwan / Dr Liang-Fu Lin [ªL«G¨j ³Õ¤h] (Ocean Center, National Taiwan University)

Abstract: Gas hydrate, also known as methane hydrate or combustible ice, is a solid, ice-like compound that forms under high-pressure and low-temperature conditions, primarily in continental margin sediments and permafrost regions. Due to its vast reserves and relatively lower carbon emissions when burned, gas hydrate has been considered a potential future energy resource. However, the stability of gas hydrate-bearing sediments is highly sensitive to natural processes such as structural development, sedimentary dynamics, sea-level changes, and human activities. These factors can induce gas hydrate dissociation, leading to gas release. The released gas may either trigger submarine landslides, posing geohazard risks, or escape into the atmosphere, contributing to greenhouse gas emissions. From both energy and environmental perspectives, the occurrence of gas hydrates in shallow marine sediments need further investigation.

Gas hydrate exploration in offshore southwestern Taiwan began in 2004 and had been systematically conducted over 15 years using a range of geological and geophysical techniques. These include 2D and 3D seismic surveys, heat flow measurements, ocean-bottom seismometer (OBS) surveys, seafloor coring, high-resolution seafloor investigations, precision sampling at gas hydrate seepage sites, chirp sonar profiling, side-scan sonar imaging, and seafloor filming and photography. Integrated geological, geophysical, geochemical, and biological evidence suggests that gas hydrates are potentially abundant in both the rifted margin of the northeastern South China Sea (a passive margin) and the submarine orogenic wedge (an active margin). This presentation provides an overview from a brief introduction of gas hydrate, the geological conditions of offshore SW Taiwan, the methods used to investigate gas hydrate occurrences, to key results that reveal the gas hydrate petroleum system in the study area.