--> Abstract: 3D Static and Dynamic Modeling of a Clastic Multilayered Reservoir with Heavy Oil: a Case Study from Comodoro Rivadavia Formation in El Alba Valle Field (Manantiales Behr Block, Golfo San Jorge Basin, Argentina), by Rodriguez Blanco, Leticia; Foster, Martin; Jarque, Gaston; Perez, Diego; and Thompson, Anthony; #90166 (2013)

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3D Static and Dynamic Modeling of a Clastic Multilayered Reservoir with Heavy Oil: a Case Study from Comodoro Rivadavia Formation in El Alba Valle Field (Manantiales Behr Block, Golfo San Jorge Basin, Argentina)

Rodríguez Blanco, Leticia1; Foster, Martin; Jarque, Gastón; Perez, Diego; and Thompson, Anthony
1[email protected]

The primary goal of this study was to determine the optimum approach -either water or polymer flood- for exploitation of El Alba Valle field. Historically the methodology used in these types of reservoirs for field development was based on the correlation of individual sandstone bodies, assuming no lateral or vertical connectivity between them. Applying this methodology, STOIIP calculations were highly conservative, pay being calculated exclusively from sands that produced oil form short-duration tests. Additionally if the sands were indeed isolated, this would have a negative impact on the potential effectiveness of any improved oil recovery strategy.

This work presents the integrated 3D static and dynamic reservoir characterization and modeling of the Comodoro Rivadavia Formation, a 45% NTG, ~500m thick succession interpreted as a multilateral and multistory fluvial system. Characterization of this reservoir is challenging due to the fact that is multilayered, with very heterogeneous sandstone bodies and multiple fluid contacts. There is only a limited set of well logs (SP, RES and DEN) and no core available. The absence of reliable PLT measurements makes geological interpretation and dynamic validation the only way to estimate which sandstones are in fact oil-bearing in the medium-long term. Additionally flow tests in the past have been proven to be unreliable: wells with water-bearing tests have subsequently produced dry oil.

A new correlation scheme was built, dividing the reservoir into 12 units using the main shaly intervals (minimum energy in the system) as stratigraphic markers due to their continuity across the field. These shaly intervals act as boundaries between which sandstone bodies are grouped together into a flow unit with a single oil-water contact. This approach was tested by dynamic simulation and found to provide a match and explanation of historical production and pressure behavior, this supporting the proposed fluvial architecture.

This integrated model was the first 3D static model in the history of the Block that was tested through dynamic simulation. The resultant model tripled the previous STOIIP, and has enabled a number of improved oil recovery schemes to be considered and the initial results from the waterflood pilot currently ongoing on the field to be evaluated.

 

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013