Eclipse Severity Levels

There are several levels of severity in ECLIPSE:

Message (Not an error, purely informative)
Comment (Probably not a data error)
Warning (Possibly a data error)
Problem (Calculation difficulties)
Error (Definitely a data error)
Bug (Suspected programming error)
NaN means “Not a Number” (Usually caused by dividing by zero or something similar)

They can be found at the end of .PRT file which is plain text file.
Example:

Error summary 
Comments               3
Warnings               7
Problems               0
Errors                 0
Bugs                   0

Default print/stop limits in Eclipse 2009.

Print limits:

Default print limit for severity 1 messages: 1000000
Default print limit for severity 2 messages: 1000000
Default print limit for severity 3 messages: 10000
Default print limit for severity 4 messages: 100
Default print limit for severity 5 messages: 100
Default print limit for severity 6 messages: 100

Stop limit:

Default stop limit for severity 1 messages: 1000000
Default stop limit for severity 2 messages: 1000000
Default stop limit for severity 3 messages: 10000
Default stop limit for severity 4 messages: 100
Default stop limit for severity 5 messages: 10
Default stop limit for severity 6 messages: 1

Make sure that the MESSAGES keyword has not been used to limit the number of messages (and comments, warnings, etc.) output by the program. You can reset message print and stop limits with keyword MESSAGES (check Eclipse manual)

Messages, Comments, Warnings

First check all messages, comments and warnings.
All of these start with an “@”, so you can find all these messages by looking for “@”, either in the PRT file or in the LOG file if you are running in batch mode. Alternatively ECLIPSE Office or PETREL RE will list all of these for you.

Messages

Give information. You do not have to take any action about messages, but have a look at each message to make sure that the information is not unexpected.
Two example are:

@--MESSAGE AT TIME 0.0 DAYS (19-OCT-1982):
@ CHECKING FOR LICENSES
@--MESSAGE AT TIME 0.0 DAYS (19-OCT-1982):
@ THE MEMORY REQUIRED TO PROCESS THE GRID SECTION IS
@ 1526 KBYTES

Comments

Also give information. You should read all comments to confirm that the model is what you want it to be.
An example is:

@--COMMENT AT TIME 0.0 DAYS (19-OCT-1982):
@ NO NON-NEIGHBOUR CONNECTIONS FOUND

If you did not expect any non-neighbor connections, then you do not have to do anything. If however you know that your reservoir has a lot of fault throws, then you may need to check your model.

Warnings

The things you should check. There may be data issues that need correcting.

Common Warning #1

@--WARNING AT TIME 0.0 DAYS (19-OCT-1982):
@ INCONSISTENT END POINTS IN SATURATION TABLE 1
@ THE MAXIMUM GAS SATURATION (1.0000)
@ PLUS THE CONNATE WATER SATURATION (0.1200)
@ MUST NOT EXCEED 1.0

Probably safe, but your gas and water SCAL tables are inconsistent. Did you know that with your data the gas saturation will never be > 0.88? Is this what you wanted? Common Warning #2

@--WARNING AT TIME 0.0 DAYS (19-OCT-1982):
@ THE BOTTOM HOLE PRESSURE LIMIT FOR WELL INJECTR1
@ HAS BEEN DEFAULTED. THE DEFAULT VALUE IS 100000. PSIA

Probably safe as long as the injector never goes to BHP control, but setting a more reasonable limit would be safer.

Problems, Errors, Bugs and NaNs

All of these also start with an “@”. Check and correct any problems and errors. If after you have fixed all problems and errors you still have either a bug or a NaN then contact your local support.

Problems

They mean there is definitely an issue. Check and fix before continuing.

@--PROBLEM AT TIME 0.0 DAYS (19-OCT-1982):
@ OIL PRESSURE IN EQUILIBRATION CALCULATION BETWEEN DEPTHS
@ 8400.0 FEET AND 8397.7 FEET HAS NOT CONVERGED.
@ CONVERGENCE ERROR = 0.86508E+33 PSI .
@ THE CURRENT NUMBER ( 100 ) OF DEPTH NODES IN THE
@ EQUILIBRATION CALCULATION IS TOO SMALL.

In this case, pointing to oil PVT table.

Errors

They mean you cannot continue without fixing your data.

@-- ERROR AT TIME 0.0 DAYS (19-OCT-1982):
@ ERROR IN PVTO TABLE NUMBER 1
@ NOT ENOUGH PRESSURE VALUES (ONLY 1) SPECIFIED
@ FOR HIGHEST RS (= 1.270 MSCF/STB)

This was the reason for the previous message, so always fix the first error message first.

NaN

Means “Not a Number”, and is usually caused by dividing by zero or something similar. NaNs sometimes happens after an Error, so if you see “NaN” anywhere in any output, then:

Fix any Error or Problem first.
If the NaN is still there, contact your local support.

@--WARNING AT TIME 0.0 DAYS (19-OCT-1982):
@ GAS IS DENSER THAN OIL WITHIN THE RESERVOIR
@ IN EQUILIBRATION REGION 1. CHECK SURFACE
@ DENSITIES, FORMATION VOLUME FACTORS, RS, RV.
@ THE PROBLEM OCCURS AT DEPTH 8725.0000
@ GAS PRESSURE = 0.4201E-01
@ OIL PRESSURE = NaN
@ (RS MAY BE SPECIFIED IN THE WRONG UNITS)

In this case, the NaN follows an error message.

See alos

ECLIPSE Convergence manual