Publications

The region immediately south of West Timor, offshore Indonesia, has been largely under-explored, with only one well drilled onshore within the Eni operated West Timor Block PSC, and no wells drilled offshore. The area is located along the Outer Banda Arc, a geologically complex, non-volcanic semicircular belt where the Australian and Asian Plates obliquely collide. The main reservoir target is the clastic Jurassic Plover formation. Imaging and resolution of the Top Jurassic horizon and the overlying accretionary section is the primary geophysical objective for prospect generation and poses a formidable challenge to marine seismic acquisition and processing. The seismic exploration history dates back to a legacy 2D survey in 1991. In 2009, a regional 2D Multiclient survey using dual-sensor broadband technology yielded significantly improved continuity of events beneath the accretionary section. Encouraged by these results, in 2010 Eni acquired a pilot program of 2D lines and subsequently a 3D survey using the same broadband acquisition technology. Broadband marine seismic via dual-sensor streamer resulted in improved resolution of the overburden and greater penetration at the target level. These benefits are a direct consequence of eliminating the receiver ghost via the dual-sensor system. Ghost-free data is rich in both low and high frequencies, has improved signal to noise ratio, and is easier to interpret since it more closely resembles the earth’s response. * PGS Singapore ** ENI Indonesia *** ENI Milan A second important contribution comes from utilizing a unique implementation of Beam Depth Migration to correctly image the complex overburden and underlying target structure. Unique aspects of this implementation include near-vertical steep dip imaging, residual multiple attenuation, and the ability to detect and correctly position weak signal. These features play an important role in imaging both the accretionary prism and the target structure. The combination of the described technologies provided significant uplift in imaging and interpretability for the development of a new play in the region.