Reservoir Pressure and Fluids Modeling to Support a 3-D Seismic Feasibility Study in the Kuparuk River Field, Alaska

Stephanie N. Erickson, Tammy L. Campbell, Dominique VanNostrand, and Blaine M. Campbell
ConocoPhillips Alaska, Inc, Anchorage, AK

A study was initiated to determine the feasibility of a new 3-D seismic survey over the Kuparuk River Field (North America's second largest oil field), where fault behavior is a key uncertainty for reservoir development. With over 1 billion barrels of oil remaining to be produced, the ability to detect and map fault behavior and reservoir conditions using a new 3-D seismic survey would greatly impact and enhance future reservoir management. Pressures and fluids in the Kuparuk reservoir have changed significantly from original conditions due to a complex reservoir management history, including injection of water, lean gas, and miscible injectant.

A rock physics and seismic modeling effort investigated changes in the seismic response for common Kuparuk stratigraphic architectures due to variations in reservoir pressures and fluids associated with historic production and injection. The modeling results suggest that the seismic response is sensitive to variations in reservoir pressure and/or fluid compositions. Consequently, changes in Kuparuk field pressures and fluids resulting from historical production/injection should be observable on a new 3-D survey. An increase in pore pressure and/or injection of compressible fluids such as miscible injectant or gas will decrease the P-velocity and impedance. In contrast, the Vp/Vs ratio will increase with pore pressure but will decrease with injection of compressible fluids, suggesting that a combination of seismic attributes may make it possible to discriminate between impedance changes due to pressure variations from impedance changes due to varying fluid compositions.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005