A method for treating a subterranean region includes running a tubular string including a plurality of sealed fluid ports distributed along its length through an upper lined wellbore section and into a lower drilled bore section which intercepts a subterranean region, wherein the lower drilled bore section includes a first fluid. A second fluid is delivered through one of the tubular string and an annulus defined between the tubular string and a wall of the bore to displace the first fluid from the annulus, wherein fluid communication between the tubular member and the annulus is provided via a displacement port in a lower end region of the tubular string. At least one of the sealed fluid ports may subsequently be opened and a treating fluid is delivered through the tubular string and into the annulus via the at least one opened fluid port to treat the subterranean region.