`WELPI`

Recognised by the OPM Flow parserSCHEDULE

The WELPI keyword is used to define a well’s productivity or injectivity index at the time the keyword is activated. Productivity and injectivity indices are a function of both bottom-hole pressure and mobility and thus will vary in time as the bottom-hole pressure and fluids produce by the well are changing. Thus, the values enter on this keyword for a given well will override any previously calculated values, or values previously entered, using this keyword. This keyword should only be invoked after a well’s connection factors have been declared via the COMPDAT keyword in the SCHEDULE section.

Notes:

The keyword is followed by any number of records with each record terminated by a “/” and the keyword should be terminated by a “/”.

Note that only a well’s currently opened connection factors, as entered via the COMPDAT keyword, are re-scaled to match the required productivity and injectivity index. See section Well Productivityon well productivity for further information on well productivity.

Note

One should not modify the productivity and injectivity index of gas wells that use:

Russell Goodrich326 Russell, D.G., Goodrich, J.H., Perry, G.E and Bruskotter, J.F "Methods of Predicting Gas Well Performance", Transactions of the ASME, Journal of Petroleum Technology (1966) 99-108. pressure square inflow equation, as declared via 'R-G' or 'YES' for the INFLOW parameter on the WELSPECS keyword in the SCHEDULE section, or

Russell, D.G., Goodrich, J.H., Perry, G.E and Bruskotter, J.F "Methods of Predicting Gas Well Performance", Transactions of the ASME, Journal of Petroleum Technology (1966) 99-108.

the general dry gas pseudo pressure inflow equation, as declared via 'P-P' for the INFLOW parameter on the WELSPECS keyword in the SCHEDULE section, or

the generalized gas pseudo pressure inflow equation, as declared via 'GPP' for the INFLOW parameter on the WELSPECS keyword in the SCHEDULE section, or

those gas wells that use the non-Darcy D factor coefficient, as declared by the DFACT property on the COMPDAT and WDFAC keywords in the SCHEDULE section.

See also the WPIMULT keyword in the SCHEDULE section to set the productivity and injectivity index for a well by scaling the current index by a scaling factor.

Records: One or more records, each terminated by /
Items per record: 2

Parameters

No.	Name	Description	Type	Field	Metric	Lab	Default
1	`WELL_NAME` manual: `WELNAME`	A character string of up to eight characters in length that defines the well name for which the well productivity index is being defined. Note that the well name (WELNAME) must have been declared previously using the WELSPECS keyword in the SCHEDULE section, otherwise an error may occur.	STRING				None
2	`STEADY_STATE_PRODUCTIVITY_OR_INJECTIVITY_INDEX_VALUE` manual: `WELPI`	A real positive value that defines the productivity or injectivity of a well at the time the keyword is activated in the input deck. Subsequent use of the keyword for a given well will override all previously entered data, including the original productivity index calculated from the well’s COMPDAT connection data. Note that: Only the connections currently opened will have their connection factors re-scaled to honor the productivity and injectivity index. Connections not opened will remain unchanged. Additional, previously defined connections added to the well at a later time, will not be influenced by a previous WELPI keyword. It may therefore be necessary to add another WELPI keyword at the time the new connections are opened, if desired. However, re-defining connections via the COMPDAT keyword resets the calculated productivity and injectivity index for those re-defined connections in the well. Subsequent usage of the keyword for the same well may lead to unintended values; use the WPI series of variables in the SUMMARY section to output and verify that the values are consistent with the desired results.	DOUBLE	Liquid stb/d/psia Gas Mscf/d/psia	Liquid sm3/day/bars Gas sm3/day/bars	Liquid scc/hour/atm Gas scc/hour/atm	1.0

Example

--
-- DEFINE WELL PRODUCTIVITY/INJECTIVITY INDEX
--
-- WELL PI
-- NAME MULT
WELPI
OP01 1.250 /
OP02 2.750 /
OP03 1.100 /
/
In the above example the oil wells are are defined as having a well productivity indices of 1.250, 2.750 and 1.100 for the OP01, OP02 and OP03 wells, respectively.
| Note One should not modify the productivity and injectivity index of gas wells that use: Russell Goodrich326
              Russell, D.G., Goodrich, J.H., Perry, G.E and Bruskotter, J.F "Methods of Predicting Gas Well Performance", Transactions of the ASME, Journal of Petroleum Technology (1966) 99-108. pressure square inflow equation, as declared via 'R-G' or 'YES' for the INFLOW parameter on the WELSPECS keyword in the SCHEDULE section, or Russell, D.G., Goodrich, J.H., Perry, G.E and Bruskotter, J.F "Methods of Predicting Gas Well Performance", Transactions of the ASME, Journal of Petroleum Technology (1966) 99-108. the general dry gas pseudo pressure inflow equation, as declared via 'P-P' for the INFLOW parameter on the WELSPECS keyword in the SCHEDULE section, or the generalized gas pseudo pressure inflow equation, as declared via 'GPP' for the INFLOW parameter on the WELSPECS keyword in the SCHEDULE section, or those gas wells that use the non-Darcy D factor coefficient, as declared by the DFACT property on the COMPDAT and WDFAC keywords in the SCHEDULE section. |
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Manual source: parts/chapters/subsections/12.3/WELPI.fodt