A method for fracturing a formation includes positioning a fluid treatment string in the formation. The fluid treatment string includes a port configured to pass fracturing fluid from within the string's inner bore to outside the string, and a sliding sleeve located inside string and configured to move by fluid pressure within the inner bore of the fluid treatment string between (i) a first position in which the sliding sleeve covers the port and (ii) a second position in which the sliding sleeve exposes the port to the inner bore. The method also includes applying a fluid pressure within the inner bore such that the sliding sleeve moves from the first position to the second position without the sliding sleeve engaging a sealing device, and pumping fracturing fluid through the inner bore and through the port to fracture a portion of the formation.