If there be within the corporate limits of said city as many as 640 acres of land, some portion of which is available at a reasonable cost, either by lease or purchase, as a drill site, then the acreage attributable to such gas well shall be located within the corporate limits of said city; but if no drill site is available at a reasonable cost within the corporate limits of said city then the governing body of said city is hereby granted power and authority to acquire by lease or purchase a suitable drill site adjacent to said city.