Abstract: Comparison of Lower to Middle Carboniferous Platform Carbonate Reservoir Development Along the Northern, Eastern and Southwestern Margins of the Precaspian Basin, Republic of Kazakhstan

SMALE, JOHN L., W. RUPERT BODDEN, DEBA BHATTACHARYYA, DAVID A. WAVREK, GRIGORI SHERMAN, VALERI SAVVIN, TOROCHEL YUGAI, ELENA SKORNYAKOVA, EDGAR VOTSALEVSKY and DMITRI SHLYGIN,

Significant petroleum reserves are contained within Lower-Middle Carboniferous platform carbonates rimming the Precaspian Basin. Wireline log analysis and petrographic examination of numerous core samples from Karachaganak, Zhanazhol and Astrakhan fields indicate that retrogradational and aggradational carbonate platform growth characterizes the northern and western margins of the basin, while progradational and aggradational growth characterizes the eastern margin. Although a large proportion of the reservoir facies in each of these fields is characterized by tight grainstones and packstones, significant porosity development occurs in specific primary depositional facies zones (e.g., the higher energy, shallow shelf deposits at Astrakhan) or as a consequence of primary and of both secondary dissolution during exposure of the platforms and fracturing (e.g., Karachaganak and Zhanazhol reservoirs). The delineation of depositional-sequence-reservoir architecture in each of these fields permits the evaluation and correlation of current productive intervals, the prediction of additional flow units and offers insight on basin-wide structural/stratigraphic factors controlling carbonate reservoir geometry.

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