Abstract: The present invention provides multi-branched wellbore systems and methods for forming and utilizing such wellbores. An access wellbore is formed substantially in a non-producing formation. From the access wellbore are drilled one or more branch wellbore into producing formations and into non-producing formations. Additional branch wellbores may be formed from the access wellbore or the branch wellbores. Seals between the access wellbore and the production wellbores are formed outside the hydrocarbon-bearing formations. Flow control devices and other devices are installed outside the access wellbore, thereby utilizing the access wellbore primarily for transporting fluids during production of hydrocarbons. The distance between the access wellbore and any other desired formation, such as the producing formations, is determined during drilling of the access wellbore, preferably by utilizing acoustic sensors deployed in a drilling assembly.