Process for characterizing the organic hydrocarbon compounds contained in a solid deposit of a geothermal plant, characterized in that at least the following steps are applied to a sample of said deposit: A) at least said sample is heated under an inert atmosphere according to a temperature sequence and at least one quantity representative of said organic hydrocarbon compounds released during at least said temperature sequence is measured continuously, said temperature sequence being such that: a) starting from a first temperature value between 50°C and 120°C, the temperature of said sample is raised according to a first temperature gradient of between 1°C/min and 50°C/min, up to a second temperature value between 180°C and 220°C, said sample is maintained at said second temperature value for a first predetermined period of time; b) starting from said second temperature value, the temperature of said sample is raised according to a second temperature gradient of between 1°C/min and 50°C/min, up to a third temperature value between 330°C and 370°C, and said sample is maintained at said third temperature value for a second predetermined period of time; c) starting from said third temperature value, the temperature of said sample is raised according to a third temperature gradient of between 1°C/min and 50°C/min, up to a fourth temperature value between 630°C and 670°C; B) starting at least from said measurement of said representative quantity of said organic hydrocarbon compounds released by said sample of solid deposit during said temperature sequence, said organic hydrocarbon compounds contained in said solid deposit of said geothermal plant are characterized. A) at least said sample is heated under an inert atmosphere according to a temperature sequence and at least one quantity representative of said organic hydrocarbon compounds released during at least said temperature sequence is measured continuously, said temperature sequence being such that: a) starting from a first temperature value between 50°C and 120°C, the temperature of said sample is raised according to a first temperature gradient of between 1°C/min and 50°C/min, up to a second temperature value between 180°C and 220°C, said sample is maintained at said second temperature value for a first predetermined period of time; b) starting from said second temperature value, the temperature of said sample is raised according to a second temperature gradient of between 1°C/min and 50°C/min, up to a third temperature value between 330°C and 370°C, and said sample is maintained at said third temperature value for a second predetermined period of time; c) starting from said third temperature value, the temperature of said sample is raised according to a third temperature gradient of between 1°C/min and 50°C/min, up to a fourth temperature value between 630°C and 670°C; a) starting from a first temperature value between 50°C and 120°C, the temperature of said sample is raised according to a first temperature gradient of between 1°C/min and 50°C/min, up to a second temperature value between 180°C and 220°C, said sample is maintained at said second temperature value for a first predetermined period of time; b) starting from said second temperature value, the temperature of said sample is raised according to a second temperature gradient of between 1°C/min and 50°C/min, up to a third temperature value between 330°C and 370°C, and said sample is maintained at said third temperature value for a second predetermined period of time; c) starting from said third temperature value, the temperature of said sample is raised according to a third temperature gradient of between 1°C/min and 50°C/min, up to a fourth temperature value between 630°C and 670°C; B) starting at least from said measurement of said representative quantity of said organic hydrocarbon compounds released by said sample of solid deposit during said temperature sequence, said organic hydrocarbon compounds contained in said solid deposit of said geothermal plant are characterized.