Abstract

: Ramnad-Palkbay sub-basin of Cauvery basin has obtained significance for petroleum exploration in view of oil/ gas finds of considerable reserves. Accordingly a massive 3D acquisition programme was drawn up in and around the finds and is being acquired phase by phase. The Ramnad phase-iv area (Fig.1), comprises a large town, namely, Ramanathapuram of about 14 sq. km. area, with high population density and severe logistics, posed a serious problem for 3D data acquisition (in a conventional way) in the town area, beneath which high hydrocarbon prospectivity was envisaged (Fig2). The township accounts for about 20% of the assigned full foldage area and had this town not been covered by 3D recovery, it would have left about 19 sq. km. hole in the 3D data volume(Fig.3).Making an advanced plan by about two months, and designing an innovative template geometry, the area has been covered in a record time of 25 days. While planning and execution of the recovery plan extreme care was taken to acquire the data adhering to the strict quality control norms to maintain data quality, covering the data gap with full foldage, with the maximum possible uniform non redundant offset distribution and also keeping a check on optimization of recovery shots not exceeding the shots in regular pattern in the town area.