1. A method of treating a subterranean formation penetrated by a wellbore, the method comprising: preparing a treatment fluid at a surface location based upon an initial model of fluid properties for the treatment fluid, the treatment fluid being formed from a first fluid stream and at least one additive fluid stream that are combined to form a treatment fluid stream that is introduced into the wellbore in a substantially continuous process; monitoring a fluid property of at least one of the streams while forming the treatment fluid to provide at least one monitored fluid property of the at least one of the streams; updating the model based upon the at least one monitored fluid property during the substantially continuous process; and adjusting at least one of the first fluid stream and the at least one additive stream based upon the updated model.