Abstract: A method of providing an annular seal around a tubular in a wellbore penetrating a subsurface formation, the method comprising providing a tubular in the wellbore, wherein an annular space (18) is formed around the tubular; providing an annular gravel pack in the annular space; wherein the method further comprises arranging a band (9a, 9b, 9c, 9d) of gel-forming material around the tubular before providing the annular gravel pack, wherein the gel-forming material is swellable in a selected fluid, and wherein the annular seal is formed by contacting the band of gel-forming material with the selected fluid; and a wellbore system comprising a gravel-packed tubular in a wellbore, wherein the tubular is provided with a band of gel-forming material in a layer around the tubular, the band being surrounded by gravel (15), and wherein the gel-forming material is swellable in a selected fluid.