C. Kruit, 1988. "Sedimentologic Reservoir Study of a Steam-Drive Project in Deltaic River Sands, East Tia Juana Field, Venezuela", Reservoir Sedimentology, Roderick W. Tillman, K. J. Weber
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A hexagon steam-flood pattern in the Middle Miocene Lower Lagunillas Sand Member was described geologically and petrophysically in anticipation of a fieldwide “M-6” steam drive in East Tia Juana field, Venezuela. Data were obtained in a seven-well hexagon centered on well 3054 and having an average spacing of 231 m (758 ft). Rubber-sleeve cores from five wells and sidewall samples from additional wells were examined. The sequence of productive sands is primarily fluvial deltaic and is overlain by a shallow marine interval. Lateral correlations emphasizing bases of channels and inundation planes were given preference over correlating log shapes. Log shapes were used in mapping local subfacies within the channels. Channel sand trends were found to be well defined on maps of 0.So, where 0.So values exceeded 0.3. Regional cross sections showing various classes of 0.So were also used to illustrate the vertical and lateral sequences of active fill, abandoned fill, and interdistributary splay sands.
The productive sands recognized in the pilot area were designated separately as D-l, D-2 and D-3. Since no permeability boundaries were interpreted to exist between these sands, vertical communication was predicted to be very good.
Several wells contained only one fluvial sand subfacies. Additional oil produced from individual wells, as a result of steam injection in the D-l sand, can be directly related to the type of channel subfacies encountered. In a well which was located primarily in the active channel fill, production of additional oil was 200,000 extra barrels; abandoned channel-fill wells produced from 0 to 50,000 extra barrels, and a well interpreted to produce primarily from a natural levee or flood basin produced only 20,000 extra barrels. These variations in production were predicted by construction of detailed geologic maps and cross sections.
Figures & Tables
This volume is a collection of papers which focus on the sedimentology of siliciclastic sandstone and carbonate reservoirs. The papers were selected to show how detailed sedimentologic descriptions, when combined with engineering or other subsurface geologic techniques, yield reservoir models which may be used for reservoir management during field development and during secondary or tertiary enhanced oil recovery. In all the papers the framework for the field descriptions relies heavily of full-diameter cores. In addition to conventional 4-inch-diameter cores, frozen and rubber-sleeve cores were utilized in one or more of the studies. In addition to cores, at least one other geologic or engineering technique is integrated into each study. This integration of sedimentologic descriptions with other techniques gives rise to synergism.