Quantifying Inter- and Intra-Channel Architecture Controls on Reservoir Performance in a Deep-Water Slope Channel System, Tres Pasos Formation, Magallanes Basin

Abstract

The Tres Pasos Fm of the Magallanes Basin in Chile records the evolution of a prograding deep-water slope system with exceptionally well exposed depositional dip-oriented middle to lower slope strata exposed at the Laguna Figueroa locality. The outcrop contains three channel complexes comprised of 18 channel elements. While analogous slope channel deposits can contain significant reservoir potential, their channelized nature creates uncertain connectivity, which can be problematic for efficient hydrocarbon production. This work seeks to quantify the influence of reservoir architecture on reservoir productivity as a function of well placement and inter-/intra-channel architecture using a high-resolution outcrop-based geocellular model. Reservoir flow simulation is performed to assess the impact of intra-channel architecture on production profiles. Simulated production data is analyzed to elucidate potential clues useful for predicting channel dimensions and connectivity in new and/or producing fields. Reservoir simulations were run for: 1) a single channel element and 2) sector models representing areas of vertically aligned versus laterally offset channel elements. All models were represented at a 2 m × 2 m × 0.25 m grid scale. Three primary facies associations (FA) capture the lithologies present in outcrop: FA1 (axial) – thick-bedded amalgamated sandstone (95% sandstone); FA2 (off-axis) – thick- to thin-bedded semi-amalgamated sandstone with few fine-grained interbeds (81% sandstone); FA3 (marginal) – thin-bedded fine- to very fine-grained sandstone with interbedded siltstone and mudstone (39% sandstone). Three scenarios were created to quantify the influence of reservoir architecture on productivity by varying the proportion and distribution of facies within each channel element. Scenarios capture a range of possible architectural frameworks from highly connected FA1-dominant to more compartmentalized FA2- and FA3-dominant conditions. Hydrocarbon production was simulated from a single extraction well at the axis of the channel element(s) and two water flood injectors 35 meters from the channel margins. Inter- and intra-channel connectivity were evaluated based on the volume and location of oil left in place following water breakthrough. The influence of well placement on productivity was quantified by rerunning each of the realizations with injectors rotated to the center of the channel(s) up- and down-gradient of the production well.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015