PETE 603, 10B
Project #3
Due: 8/9/10
Compare simulation of immiscible (water/oil) displacement results for streamline simulation
(Frontsim). Investigate the effect of grid size, number of streamlines, and frequency of
streamline updating on simulation results. Prepare a written report documenting your work
on this project.
Background
A Frontsim data file is provided in text format, PROJ3F.DATA (for Frontsim). You may
use either the PC version of the simulator by checking out a departmental license (via VPN
if off campus), or use a web-based remote desktop to execute the simulator on a
departmental server
This data files present a base case detailing a 32x1x8 cross section model of a reservoir with
three zones with thickness of 100, 100 and 200 ft, respectively. The top and bottom zones
have permeability of 10 md, and the middle zone has permeability of 100 md. The injection
rate is 1000 STB/day (approximately 10% of pore volume per year) over a 10-year period.
For this base case, water and oil have the same density, and an endpoint mobility ratio of
1.0. Compare to your most accurate Eclipse Simulation from Project 2.
1. Compare the simulation times and quality of results for Eclipse versus Frontsim as
the grid is refined. Consider at least three 2x2 grid refinements, keeping the
reservoir volume, zone thickness values and completed thickness intervals constant.
Use watercut as a function of time to determine quality of results, compared to the
finest grid (256x1x64 gridblocks) Eclipse case. For each grid, consider the effect of
time step size on results.
2. Compare the simulation times and quality of results endpoint mobility ratio of 1/9
(favorable) and significant gravity effect. Achieve this by:
a. increasing water viscosity by a factor of 3, and decreasing all values of the
water relative permeability function table by a factor of 3.
b. increasing water density to a more realistic value of 65 lbm/ft3.
3. Beginning with provided data files, investigate the effect of unfavorable endpoint
mobility ratio of 10. Achieve this by increasing oil viscosity to 15 cp.
4. Provide saturation grid maps and streamline maps at 5 years of production using
FloViz for at least one grid for cases 1,2, and 3 above.
Reporting Details:
Include a brief Executive Summary outlining this project and presenting major
results/recommendations/conclusions. This summary should be intended for someone not
participating in our class, but generally knowledgeable on the topic of reservoir simulation.
The Results section should present the deliverables listed above, and discuss each result
presented. Include relevant figures and discussion of sensitivity studies (including number
of streamlines and frequency of streamline updating for each grid) that were necessary to
achieve accurate and stable simulation results.
Remote Desktop
Getting started is at http://pe-virtual6.pe.tamu.edu/ts/en-US/default.aspx
Keywords / Simulation
Beginning with the base data file from Project 2 (PROJ2E.DATA), the following changes
were made to create the PROJ3F.DATA file.
The files, including the Frontsim User’s Guide .pdf were placed in the \\pefile.pe.tamu.edu\shares\Classes\pete603 web folder (frontsim_ug.pdf). Comparison of
results between PROJ2E.DATA, PROJ3F.DATA, and PROJ3F-.DATA is in
Run_Comparison.pdf (NOTE that the only change for PROJ3F-1.DATA changed TSTEP to
100*36.5, however, TSTEP should probably not be used for rate/streamline updating, see
User’s Guide).
Runspec Section:

Comment out (or delete) existing RUNSPEC section (everything before GRID).

FRONTSIM keyword (Accept only FrontSim keywords)

DIMENS keyword (This keyword defines the basic size of the simulation grid).

FIELD keyword (This indicates that field units are to be used).

OIL keyword (This keyword indicates that a run contains an oil phase. It should be
specified whenever an oil
phase exists or could exist).


WATER keyword (This indicates that the run contains water as an active phase,
whose saturation can vary).
Grid Section:

Use DXV and DYV (These keywords specify the size of the cells in the X or Ydirection), instead of DX and DY.

Use DZV (This keyword specifies the size of the cells in the Z-direction) and
DEPTHZ (Defines depth to (NDIVIX+1)*(NDIVIY+1) top grid nodes), instead of
DZ and TOPS. On DEPTHZ, the “+1” part is about the gridblock boundaries, as we
discussed related to the Minimum Time Algorithm.

Comment out OLDTRAN
Summary Section:

Comment out RPTSMRY.
Other Notes:
TUNEFSPR: This keyword sets the tuning options for the pressure solver.
TUNEFSSA: This keyword sets the tuning options for the saturation solver.
On FlowViz:



See .bmp files on pe-file.
o For PROJ3F.DATA, it seems clear that the streamlines were calculated at the
beginning of the first year (straight lines), and never updated prior to the end of
the first year.
o For PROJ3F-1.DATA, streamline updating every 0.1 year with the favorable
mobility ratio let’s some of the injected water flow out of the high perm zone,
and results in water in the high perm zone not breaking through at the producer
as quickly.
First, open the .GRID file for the case you want. Note you can do File, Remove Model
to load a different case.
See View, Timesteps. Hitting play (“>”) shows continuous screen updates. Usually the
next button to the right is better (“>|”), especially with remote app. To get back to the
beginning, click on the first time point. Note that streamlines change over time,
meaning more updates could improve simulation accuracy.
o Probably a slightly favorable shock front mobility ratio, even though the end
point mobility ratio is 1.0. You could determine this using the saturation at the
fractional flow curve tangent point tying to initial saturation.

See Scene, Streamlines, Streamline Display. Setting the filtering to about every 5th
makes visualization possible showing about 10 times as many streamlines in geologic
layer 2 as in geologic layer 1.