--> ABSTRACT: AVO Screening in Frontier Basins: An Example from the Gulf of Papua, Papua New Guinea, by Davies, Amanda; Burmaz, Bob ; Reed, Rod; Reiser, Cyrille; #90142 (2012)
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Previous HitAVONext Hit Screening in Frontier Basins: An Example from the Gulf of Papua, Papua New Guinea

Davies, Amanda *1; Burmaz, Bob 3; Reed, Rod 2; Reiser, Cyrille 4
(1) MultiClient - Reservoir, Petroleum Geo-Services, Singapore, Singapore.
(2) MultiClient, Petroleum Geo-Services, Perth, WA, Australia.
(3) Data Processing, Petroleum Geo-Services, Perth, WA, Australia.
(4) MultiClient - Reservoir Characterisation, Petroleum Geo-Services, London, United Kingdom.

There has been a recent resurgence of interest in the gas potential of the Gulf of Papua enhanced by ExxonMobil’s recent announcement of the development of new LNG facilities on the East Coast of the Gulf. New 2D and MC3D surveys have been acquired over the area in recent times. The most recent being PGS’s Solwara MultiClient 3D survey.

Although most of the discoveries in Papua New Guinea are from the highland areas the Gulf is a proven hydrocarbon province with gas/condensate accumulations previously discovered in several reef build-ups. Exploration in the Gulf has mainly been near-shore and exploration has then concentrated on Miocene biohermal reef build-ups on pre-Mesozoic highs. Gas accumulations have been discovered along this reef trend, namely the Pasca & Pandora Fields.

During the Late Miocene to Early Pliocene clastic sediment input resulted from compression and uplift of the hinterland. Sediments from the Papuan Fold Belt produced clastic dominated deltas into the Gulf area. These are thought mainly to be deposited in the topographic lows or low relief structures and may have bypassed the rapidly growing compressional highs. Although this play is untested offshore there is good evidence that these sandy facies exist and could contain hydrocarbons.

On the first phase of acquisition tests was carried out using an efficient screening workflow called “Prospect Scanner” developed to highlight areas of Amplitude-Versus-Offset (Previous HitAVONext Hit) Previous HiteffectNext Hit in large 3D seismic datasets. It uses pre-stack seismic gathers to extract Previous HitAVOTop attributes, such as compressional and shear reflectivities, which are then recursively inverted to derive acoustic and shear impedance volumes. These are then loaded into conventional interpretation package for further understanding of the lithology-fluid anomaly. Using idealized cross-plot derived from well data the relationship between Vp/Vs ratio and the Ip values give a good indication of the fluid and lithology of the tested interval.

The lead analysed shows a Vp/Vs anomaly shows ponding geometry which fits to structure down dip and relies on a pinchout at the crest of the structure. The Vp/Vs vs Ip cross-plot shows clustering of the sand anomaly and good separation from the majority of the plot. These points correspond to the idealized location for a gas sand in the crossplot.

Past concerns regarding lateral prediction of reservoir presence and quality associated with the basin floor fans can be addressed through this workflow.

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California