GEM now accepts the *TURB sub-keyword for the *PERF, *PERFV, *PERFRG,
and *PERFVHY keywords to activate the turbulent skin modification of the layer
reservoir gas phase productivity/injectivity calculation. An additional parameter
value (the D-factor) must be entered for each layer on the perforation line when
this option in is force. GEM now also supports two different ways of accounting
for the layer gas phase productivity/injectivity changes due to the property changes
which the reservoir gas undergoes as the pressure changes from the grid block
value to the wellbore value. The first way, activated by the *QUAD sub-keyword
of *PERF, *PERFRG, *PERFV, and *PERFVHY, is the quadratic inflow
technique, in which the gas viscosity is assumed to remain at the grid block value
and the gas density is assumed to vary linearly with pressure. The second,
activated with the *PSEUDOP sub-keyword, includes a full recalculation of the
gas density and viscosity at the wellbore pressure. No additional data are
necessary for the *QUAD and *PSEUDOP modifications; the two cannot be
applied simultaneously, as they represent two different ways of treating the same
effect. Please consult the manual pages in this chapter describing the *PERF,
*PERFRG, *PERFV, and *PERFVHY keywords for more information.