NOVELTY - The method involves assessing physical parameters of rock volume within a reservoir in situ. A parameter indicative of fracture connectivity e.g. alpha is determined or predicted (210). A change in alpha is determined (215) over time to monitor change in fracture connectivity within the reservoir. The alpha is determined or predicted empirically from rock volume porosity and rock volume permeability.    USE - Method for monitoring fracture connectivity in geothermal or hydrocarbon reservoir.    ADVANTAGE - The production efficiency of a geothermal or hydrocarbon well is increased by increasing the degree of fracture interconnectedness or connectivity throughout the rock in all directions, and/or between areas of relatively high fracture interconnectedness localized around separated defect sites in the rock, by increasing or maximizing connected breakdown of cement bonds (typically calcite or silica) between harder rock particles or aggregates of particles of the rock, increasing bulk permeability through the rock. This achieved by pressurizing a fluid (liquid or gas) through the well-bore under pressure controlled to achieve or approach a desired degree of such fracture interconnectedness or connectivity. The alpha and/or changes in alpha are monitored during fluid pressurization through wellbore to control pressurization, preferably to acquire a desired degree of fracture connectivity for improving reservoir productivity and performance.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a method for determining pressurization of a well-bore in a geothermal or hydrocarbon reservoir;    (2) a method for monitoring permeability in a geothermal or hydrocarbon reservoir;    (3) a method for controlling permeability in a crustal rock volume of a geothermal or hydrocarbon reservoir; and    (4) a system for monitoring or controlling fracture connectivity in a geothermal or hydrocarbon reservoir.    DESCRIPTION OF DRAWING(S) - The drawing shows a flow diagram of the method for fracture monitoring/control utilizing the system.    Step for determining and predicting alpha from physical parameters (210)    Step for Step for determining change in alpha (215)    Step for pressurizing well-bore (220)    Step for measuring reservoir activity (230)    Step for determining alpha or change in alpha from monitored activity (240)