A method of performing an operation on an earth formation (16, 46) within an existing borehole, comprising: deploying a carrier in the existing borehole, the carrier including a downhole component (18, 52) configured to perform the operation on the earth formation (16, 46) within the existing borehole according to one or more operational parameters; generating a simulation model of the operation based on information known prior to the operation, the simulation model being a mathematical model configured to estimate a condition based on selected operational parameters used as input to the simulation model, the condition including at least one of a surface condition and a downhole condition; modelling the operation by using the one or more operational parameters as input to the simulation model; performing the operation according to the one or more operational parameters; measuring the condition at a selected time during the performed operation, and generating measurement data representing the measured condition; tuning the simulation model based on the measurement data, wherein tuning the simulation model includes: estimating the condition for the selected time at which the condition was measured based on the simulation model; comparing the estimated condition to the measured condition, and determining a difference between the estimated condition and the measured condition; based on the difference being greater than a selected acceptable difference, adjusting the simulation model so that the estimated condition matches the measured condition; selecting and applying a hypothetical adjustment to the one or more of operational parameters used as input to the tuned simulation model to generate predicted conditions of the operation, the predicted conditions including effects on the formation of the hypothetical adjustment; and applying the hypothetical adjustment to the operation if the predicted conditions generated by the tuned simulation model have been determined to represent an improvement to the operation, wherein applying the hypothetical adjustment to the operation includes adjusting the one or more operational parameters used in performing the operation according to the hypothetical adjustment. deploying a carrier in the existing borehole, the carrier including a downhole component (18, 52) configured to perform the operation on the earth formation (16, 46) within the existing borehole according to one or more operational parameters; generating a simulation model of the operation based on information known prior to the operation, the simulation model being a mathematical model configured to estimate a condition based on selected operational parameters used as input to the simulation model, the condition including at least one of a surface condition and a downhole condition; modelling the operation by using the one or more operational parameters as input to the simulation model; performing the operation according to the one or more operational parameters; measuring the condition at a selected time during the performed operation, and generating measurement data representing the measured condition; tuning the simulation model based on the measurement data, wherein tuning the simulation model includes: estimating the condition for the selected time at which the condition was measured based on the simulation model; comparing the estimated condition to the measured condition, and determining a difference between the estimated condition and the measured condition; based on the difference being greater than a selected acceptable difference, adjusting the simulation model so that the estimated condition matches the measured condition; estimating the condition for the selected time at which the condition was measured based on the simulation model; comparing the estimated condition to the measured condition, and determining a difference between the estimated condition and the measured condition; based on the difference being greater than a selected acceptable difference, adjusting the simulation model so that the estimated condition matches the measured condition; selecting and applying a hypothetical adjustment to the one or more of operational parameters used as input to the tuned simulation model to generate predicted conditions of the operation, the predicted conditions including effects on the formation of the hypothetical adjustment; and applying the hypothetical adjustment to the operation if the predicted conditions generated by the tuned simulation model have been determined to represent an improvement to the operation, wherein applying the hypothetical adjustment to the operation includes adjusting the one or more operational parameters used in performing the operation according to the hypothetical adjustment.