Abstract: Middle to Upper Jurassic Clastic Reservoirs in the Petroleum Basins of Western Kazakhstan: Parasequence Architecture Controls on Hydrocarbon Production

SMALE, JOHN L., MICHAEL DROPKIN, DEBA BHATTACHARYYA, MIKHAIL KOROSTYSHEVSKY, ALEXEI PRONIN and SAULE GAISINA

Major petroleum reserves are confined to Middle-Upper Jurassic fluvial-deltaic to coastal marine clastic reservoirs in the Buzachi and Mangyshlak sub-basins of western Kazakhstan. Analysis of wireline logs and core samples suggests that the reservoirs in the Arman and Kalamkas (Buzachi) and Uzen and Zhetybai fields (Mangyshlak) consist of stacked aggradational and retrogradational parasequences corresponding to a depositional regime which includes fluvial channel and channel-fill processes, swamp, distributary mouth-bar, delta-lobe and nearshore marine facies. Reservoir quality sandstones are arkosic to sub-litharenite in composition, and observed intergranular porosity is largely a consequence of both dissolution of an early generation of carbonate cement followed by a later stage of feldspar dissolution. Petrophysical parameters (porosity and hydrocarbon saturations) in combination with initial well test and production data aid in proper correlation of pay zones within the parasequence stacking patterns. The delineation and modeling of the depositional sequence architecture is crucial to effective reservoir management and the prediction of additional flow units.

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