A method of creating a horizontal wellbore section comprises drilling the section in at least two stages. The method comprises drilling a first horizontal bore section. The first horizontal bore section is then provided with a first liner having a wall including initially-closed flow ports. The first liner isolates the wall of the first bore section. A second horizontal bore section is then drilled beyond the first horizontal bore section. The second horizontal bore section is provided with a second liner. Stimulation fluid is then directed into the first and second liners so that the stimulation fluid passes through the wall of the second liner to stimulate the second horizontal bore section. The flow ports in the wall of the first liner are then opened so that the stimulation fluid passes through the wall of the first liner to stimulate the first horizontal bore section.