In 2005, Landmark Graphics
announced that they had developed a simulator that was "five times faster than existing
technology". We have some evidence that indicates "five
times slower" would be much closer to the true number.
In 2004, developers of Landmark's new simulator reported its performance1 on the black oil industry benchmark problem from the
Ninth SPE Comparative Solution Project (SPE9)2. The reported cpu time on a 3.05 GHz PC is
seconds, with 17.0 seconds in the linear solver. Sensorís cpu time on
a 2.8 GHz PC of 2004 vintage* is 8.2 seconds, with 5.0 seconds in the linear
solver. Sensor data and output files are
spe9.out. Sensor is 3 or 4 times faster than Nexus on this problem, in
both solver and non-solver time. On a per-Newton iteration basis,
Sensor is 2 or 3 times faster, but Nexus
requires 32% more of them to complete the run (56 for Sensor, 74
for Nexus). VIP was reported as being only 30% slower than Nexus and took
112 Newtons. In terms of cpu time per Newton iteration, Nexus
was shown to be no faster than VIP in either total time or solver time.
Of the eight participants in the 1995
SPE9 Comparative Solution Project, Sensor was reported as having the fastest time2.
Sensor's superiority was prominently noted in the 1995 paper : "First, the formulation in the SENSOR program does allow a
significant reduction in the total number of Newton iterations required to
solve the problem". At that time, Sensor
reportedly took 55 Newtons, while CMG took 256, Eclipse 142, and VIP
Our experience and feedback from
clients is that Sensor usually runs 3 to 10 times faster than other
simulators, regardless of problem size. The lower end of the range applies
to black oil, the upper end to compositional. Performance comparisons for this
problem are representative of that commonly observed for black oil.
We encourage you to answer the question
yourself - Who's Fastest? For an evaluation, please contact
If you want to know what makes Sensor
so fast, see the first paragraph of our Why Sensor? page, and Q&A
page 1 question 3.
* Intel Xeon Nocona 2.8 GHz, 1MB L2, 800 MHz FSB,
running Windows XP
** Want to see an even faster
spe9 run? The Sensor data given above is untuned, except for the usual
formulation and solver selection, and timestep size selections initially and
at times that well constraints are changed. The data file
spe9_tol2.dat has an additional entry for solver
tolerance, TOLERANCE 2. Run this data in Sensor for a 12%
speedup. Total cpu drops from 8.2 down to 7.2 seconds on our old 2.8 GHz
machine, and Sensor is then 4 to 5 times faster than Nexus on this
1. Coats, B.K., Fleming,
G.C., Watts, J.W., Shiralkar, G.C., and Rame, M., "A Generalized Wellbore
and Surface Facility Model, Fully
Coupled to a Reservoir Simulator", SPE Reservoir Evaluation and
Engineering, Vol. 7, No. 2, April, 2004.
2. Killough, J.H., "Ninth SPE Comparative Solution
Project: A Reexamination of Black-Oil Simulation", SPE 29110, presented
at the 13th SPE Symposium on Reservoir Simulation, San Antonio, TX, Feb.