--> ABSTRACT: When 3-D PSDM Data Turns Your Geologic Model Upside Down, by Fisher, George; #90135 (2011)

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When 3-D PSDM Data Turns Your Geologic Model Upside Down

Fisher, George 1
(1)Exploration, EPC Munai, Almaty, Kazakhstan.

When 3D PSMD Turns Your Geologic Model Upside Down

Block 8 in located in the South Emba region of the Pricaspian Basin of Western Kazakhstan. The area witnessed extensive exploration in the Soviet period (1970-1992). Over 6,000 kms of 2D seismic was acquired during that period and 50 wells were drilled. . The Sholkara salt dome alone saw 11 wells drilled to explore pre-salt targets. Of the11 wells, 4 penetrated the pre-salt and were declared “non-commercial”. The license was awarded to EPC Munai, a joint venture between LG International and SK Energy in 2006.

Between 2007 and 2008 over 1500 km of 2D seismic data was acquired. Based on the 2D seismic and well interpretation Sholkara was thought to represent a pre-salt paleo-high with a Lower Permian clastic wedge pinching out over the crest. The “paleo-high” was believed to represent a Late Carboniferous compressional feature with poor reservoir potential. No evidence of carbonate buildup in the immediate area was observed in the wells or on the seismic.

In 2009 EPC Munai acquired 200 kms of 3D seismic. The western portion of the pre-salt feature in Sholkara reveals in great detail, aspects of the paleo-high which now appear to be part on an extensive carbonate buildup associated with a major regional reverse fault. Carbonate features observed include: prograding sigmoids, shoals (possible), down slope pinnacle reefs, inner lagoons, drowned surfaces, fringing and patch reefs, and debris flows adjacent to an escarpment. The features identified on the seismic have resulted in a re-interpretation of the existing well data and the emergence of a new geologic model. EPC Munai now believes Sholkara to represent an isolated carbonate buildup with significant potential. EPC Munai plans on drilling Sholkara in the future.

 

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.