Publications

Acquisition of Indonesia's largest OBC seaismic Survey in a challenging, remote, socially and environmentally sensitive Area

Proceedings Title : Proc. Indon. Petrol. Assoc., 34th Ann. Conv., 2010

Shallow water OBC operations are always challenging, but the unique and remote environment of Berau Bay makes OBC acquisition particularly difficult. The region is remote and far from logistic support with four tidal changes per day, high currents, shallow water with numerous social and environmental sensitivities. The existence of sensitive mangrove along the coast and nearby local communities together with the risk of malaria drove the decision not to open an onshore camp. The risk of malaria was significantly reduced by locating the crew offshore beyond the range of the disease carrying anopheles mosquito. The entire seismic project was managed as an offshore operation with 250 people living and working offshore. Two large barges were used for accommodation and workspace. All Indonesian and industry regulations and guidelines were followed to ensure that the seismic operation did not impact the environment oradversely affect local communities. This was particularly important as the area is home to several protected species, including marine mammals (dolphins) and sea turtles. Since the local communities depend upon small scale fishing activities, it was important for the seismic crew to work in harmony with the local fishermen. The Ocean Bottom Cables and source lines were configured to acquire high fold, wide azimuth data in the most efficient manner possible. Source lines were laid out parallel to the seabed cables with allowed minimum downtime whilst receiver cables were being moved. The ‘single line roll’ geometry that consists of seven receiver lines 4.8km each, spaced evenly at 500m interval is shown in Figure 7. The cables were laid parallel to the water depth contours, ranges from 4m to 15m. Five source lines were shot per patch, parallel to the cable layout as shown in Figure 7. The survey covered 600 km2 with total record of 270,000, the largest 3D OBC survey in Indonesia.The survey was completed in eight months and reached 1.4 million man hours without a recordable HSE incident. The myriad of high risk HSE activities: vessels movement, hundreds boat to boat transfer per day, cable deployment and retrieval, etc., were performed without a major incident. Environmental and social management plan was executed as designed, ensuring minimal disturbance to the bay marine and indigenous people.

Log In as an IPA Member to Download Publication for Free.
or
Purchase from AAPG Datapages.