Abstract: Reservoir
Characterization, Modeling, and
Simulation
in the Welch San Andres Field
Rene Ulmschneider
As a part of a DOE funded Class II project aimed at improving oil recovery in shallow shelf carbonate reservoirs, detailed characterization, modeling and reservoir
simulation
is ongoing in Oxy USA's West Welch Unit in the Welch, San Andres field. The initial effort at modeling the
reservoir
, which is described in this report, is based on all the available core and log data in the
study
area. A final report will compare these results to
reservoir
modeling enhanced by high resolution seismic data obtained from cross wellbore tomography.
The reservoir
model was built using the following methodology:
(1) Determine sequence stratigraphic framework from core data.
(2) Identify rock fabrics from thin sections.
(3) Quantify porosity versus permeability relationship for each rock fabric.
(4) Identify rock fabrics from log data.
(5) Use unique porosity versus permeability relationship for each rock fabric to transform log porosity to permeability.
(6) Define reservoir
model flow units using sequence stratigraphic framework and identified rock fabrics.
Each layer (flow unit) is then mapped, gridded and exported to the simulator. The simulation
can then be compared to actual production history. Using this methodology a good history match was easily obtained from the
simulation
with very little modification of the
simulation
parameters in two different Welch field model areas. These results give great confidence in the subsequent
simulation
of
reservoir
response to CO2 flooding.
AAPG Search and Discovery Article #90960©1995 AAPG Southwest Section Meeting, Dallas, Texas