add sensitivity analysis to doc

Author: softwareengineerprogrammer

docs/Fervo_Project_Red.md.jinja

@@ -199,6 +199,18 @@ This 8-year forecast establishes a testable predictive baseline, which can be fu
 and recalibrated as additional multi-year operational data becomes available
 to determine if late-stage variations represent minor transients or the onset of non-linear geological thresholds.
 
+#### Sensitivity Analysis: Effective Number of Fractures
+
+To evaluate the bounding envelope of the reservoir's thermal drawdown, a sensitivity analysis was performed on the effective `Number of Fractures`.
+The calibrated baseline model assumes {{ input_params['Number of Fractures'] }} parallel fractures.
+By varying this parameter (ranging from 57 to 69 fractures), the analytical model demonstrates the sensitivity of the
+long-term thermal decline to the idealized fracture surface area.
+
+![](_images/fervo_project_red-2026_production-temperature-data-vs-modeling-fracture-sensitivity-1.png)
+
+*Detail view of the sensitivity curves overlapping the empirical steady-state data (Years 0–3):*
+
+![](_images/fervo_project_red-2026_production-temperature-data-vs-modeling-fracture-sensitivity-2.png)
 
 ## Discussion