Abstract: Seismic Quality Improvement in the Papuan Fold Belt of PNG

ELLIS, DAVID, MARK FOSTER, CARLOS DUQUE

Until recently the quality of seismic data in the Papuan fold belt, for example over the Hides gas field in the Western Highlands of PNG, was too poor to be of much use in the delineation and development of the discovery. The severe, karstified-limestone topography covered in dense rainforest and vegetation gave rise to seismic data lacking in coherent, reflected energy. Numerous attempts over nearly a decade by reprocessing to produce interpretable stack or migrated images failed owing to the basic absence of signal.

Then in 1995, and again in 1996, new seismic data over the field was acquired with effort concentrated on obtaining good coupling of the seismic sources and receivers into the near-surface limestone, so by-passing the problems associated with the weathered or seismically impenetrable near-surface. The new seismic has been processed to reveal believable, interpretable reflected data over the survey area.

This paper concentrates on the challenges faced by the seismic processing of these latest vintages of data. Although signal has been recorded by the tender-loving-care approach of the acquisition, data quality still relies heavily on high fold of stack. The fundamental fact that reflected data can barely, if at all, be seen on pre-stack gathers impacts the strategies that the processor has to employ to process the data optimally. Even with the better quality seismic acquisition, the Western highlands of PNG can still trap the unwary into erroneous processing parameter decisions, which can in turn result in some spectacularly mis-stacked seismic sections. This paper describes the important seismic data processing strategies which are required under these circumstances.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria