1. A method of performing an oilfield operation of an oilfield having at least one wellsite, each wellsite having a wellbore penetrating a subterranean formation for extracting fluid from an underground reservoir therein, the method comprising: obtaining a plurality of real-time parameters from a plurality of sensors disposed about the oilfield, wherein the plurality of real-time parameters comprise at least one selected from a group consisting of real-time flow rate data and real-time pressure data of the wellbore; configuring a gridless analytical simulator for simulating the underground reservoir based on the plurality of real-time parameters; generating real-time simulation results of the underground reservoir and the at least one wellsite in real-time using the gridless analytical simulator; and performing the oilfield operation based on the real-time simulation results.