| Abstract Submission No. | ABS-2.4-0217 |
| Title of Abstract | Long-distance migration of methane and development of sediment-wave conduits facilitating vertical free-gas migration near the gas-hydrate stability zone of the Cauvery¿Mannar Basin. |
| Authors | Palle Jyothsna*, Nittala Satyavani |
| Organisation | CSIR-National Geophysical Research Institute |
| Address | NGRI colony, Uppal Road Hyderabad, Telangana, India Pincode: 500007 E-mail: jyo.sarika@gmail.com |
| Country | India |
| Presentation | Poster |
| Abstract | The Cauvery Basin is the southernmost among the Mesozoic rift basins of India. It is located between India and Sri Lanka along the eastern continental margin of India. It is endowed with an active petroleum system. The present study area lies in the Gulf of Mannar¿Ramnad¿Palk Bay sub-basin, situated near the recent gas discovery in the deepwater block CY-DWN-2001/2 of the Cauvery Basin. An integrated interpretation of 2D and 3D seismic data reveals the widespread occurrence of a Bottom Simulating Reflector (BSR), indicating the presence of gas hydrates and underlying free gas. The landward limit of the hydrate stability zone, known as the feather edge, is distinctly identified on seismic line CY1-06. Beneath the Base of the Hydrate Stability Zone (BHSZ), a thick free gas zone exhibits lateral migration towards shallower strata near the continental shelf break. Faults act as key conduits, facilitating the migration of methane from deeper hydrocarbon reservoirs to shallower levels, where gas hydrate formation occurs. Moreover, sediment waves near the shelf break appear to channel vertical gas migration, creating a minor slope break visible in seismic line CY1-02 and corroborated by bathymetric data. Correlation with well CY-DW-F-1 provides further evidence of methane gas encountered during drilling. Additionally, gas flares reported in previous studies from the Cauvery Basin provide important evidence of ongoing subsurface fluid migration processes. |
| Keywords | Free gas migration, sediment waves, gas hydrate stability zone |