diff --git a/src/geophires_x/WellBores.py b/src/geophires_x/WellBores.py
index 90ae0349..f0633ebf 100644
--- a/src/geophires_x/WellBores.py
+++ b/src/geophires_x/WellBores.py
@@ -898,7 +898,7 @@ def __init__(self, model: Model):
         )
         self.injection_reservoir_pressure = self.OutputParameterDict[self.injection_reservoir_pressure.Name] = OutputParameter(
             Name="Calculated Injection Reservoir Pressure",
-            value=self.Phydrostatic.value,
+            value=-1,
             UnitType=Units.PRESSURE,
             PreferredUnits=PressureUnit.KPASCAL,
             CurrentUnits=PressureUnit.KPASCAL
@@ -1092,7 +1092,21 @@ def Calculate(self, model: Model) -> None:
                                                                               self.overpressure_depletion_rate.value)
 
         if self.overpressure_percentage.Provided:
-            # calculate the injection reservoir pressure as a function of time if overpressure is provided
+            # if we are doing an overpressure calculation, it is possible that the user has chosen to
+            # split the reservoir into two parts - the deeper, overpressured Production Reservoir,
+            # and a shallower, lower pressure Injection Reservoir.
+            # If so, calculate the injection reservoir pressure as a function of time if overpressure is provided.
+            # If the injection reservoir temperature or pressure are not provided, calculate a default for them.
+            if self.injection_reservoir_depth.Provided:  #this means they must be doing a split reservoir
+                if not self.injection_reservoir_temperature.Provided:
+                    self.injection_reservoir_temperature.value = (model.reserv.averagegradient.value * self.injection_reservoir_depth.value) + model.reserv.Tsurf.value
+                if self.injection_reservoir_pressure.value < 0:
+                    self.injection_reservoir_pressure.value = get_hydrostatic_pressure_kPa(self.injection_reservoir_temperature.value,
+                                                                                        model.reserv.Tsurf.value,
+                                                                                        self.injection_reservoir_depth.value,
+                                                                                        model.reserv.averagegradient.value * 1000.0,
+                                                                                        model.reserv.lithostatic_pressure(model.reserv.rhorock.value,
+                                                                                                               self.injection_reservoir_depth.value))
             self.injection_reservoir_initial_pressure.value = self.injection_reservoir_pressure.value = get_hydrostatic_pressure_kPa(self.injection_reservoir_temperature.value,
                                                                                    model.reserv.Tsurf.value,
                                                                                    self.injection_reservoir_depth.value,
diff --git a/tests/examples/example_overpressure.txt b/tests/examples/example_overpressure.txt
index a6a27193..aa8c9672 100644
--- a/tests/examples/example_overpressure.txt
+++ b/tests/examples/example_overpressure.txt
@@ -12,13 +12,13 @@ is used in for electricity application with a reinjection temperature of 50deg.C
 *************************************
 Overpressure Percentage, 155.0
 Overpressure Depletion Rate, 10.0
-Injection Reservoir Temperature, 101.1
-Injection Reservoir Depth, 1001.1
-Injection Reservoir Inflation Rate, 202.2
+Injection Reservoir Temperature, 101.1,      degC
+Injection Reservoir Depth, 1001.1,      meters
+Injection Reservoir Inflation Rate, 202.2,    kPa/yr
 Reservoir Model,1,                        			---Multiple Fractures reservoir model
 Reservoir Depth,3,                     				---[km]
 Number of Segments,1,                  				---[-]
-Gradient 1,65,                          			---[deg.C/km]
+Gradient 1,50,                          			---[deg.C/km]
 Maximum Temperature,400,                  			---[deg.C]
 Number of Production Wells,2,            			---[-]
 Number of Injection Wells,2,            			---[-]
@@ -27,7 +27,7 @@ Injection Well Diameter,9,					---[inch]
 Ramey Production Wellbore Model,1,       			---0 if disabled  1 if enabled
 Production Wellbore Temperature Drop,.5,			---[deg.C]
 Injection Wellbore Temperature Gain,0,   			---[deg.C]
-Production Flow Rate per Well,80,       			---[kg/s]
+Production Flow Rate per Well,70,       			---[kg/s]
 Fracture Shape,3,                       			---[-] Should be 1 2 3 or 4. See manual for details
 Fracture Height,900, 						---[m]
 Reservoir Volume Option,3,              			---[-] Should be 1 2 3 or 4. See manual for details