A tubular assembly (500, 600, 700, 800) adapted for downhole use in wells, the tubular assembly comprising: an upstream manifold (502, 802) adapted to receive a gravel-laden slurry; a gravel packing conduit (504, 604, 704, 804) in fluid communication with the upstream manifold and extending longitudinally away from the upstream manifold; wherein the gravel packing conduit is adapted to receive at least a portion of the gravel-laden slurry from the upstream manifold; wherein the gravel packing conduit includes at least one flow path adapted to be in fluid communication with an annulus between a wellbore wall and the tubular assembly when the tubular assembly is disposed downhole in a well; wherein the gravel packing conduit is adapted to communicate gravel-laden slurry into the annulus during isolation forming operations; and wherein the gravel packing conduit is isolated from direct fluid communication with a downstream flow path (510, 610, 810); a transport conduit (508, 608, 708, 808) in fluid communication with the upstream manifold and in fluid communication with the downstream flow path; and a leak-off conduit (506, 606, 706, 806); wherein the leak-off conduit is in at least partially restricted fluid communication with the upstream manifold; wherein the leak-off conduit is in fluid communication with the downstream flow path in a region longitudinally spaced from the upstream manifold; and wherein the leak-off conduit is in fluid communication with the annulus through permeable media (518, 618, 818) adapted to retain particles while communicating fluids providing fluid leak-off from the annulus during the isolation forming operations. an upstream manifold (502, 802) adapted to receive a gravel-laden slurry; a gravel packing conduit (504, 604, 704, 804) in fluid communication with the upstream manifold and extending longitudinally away from the upstream manifold; wherein the gravel packing conduit is adapted to receive at least a portion of the gravel-laden slurry from the upstream manifold; wherein the gravel packing conduit includes at least one flow path adapted to be in fluid communication with an annulus between a wellbore wall and the tubular assembly when the tubular assembly is disposed downhole in a well; wherein the gravel packing conduit is adapted to communicate gravel-laden slurry into the annulus during isolation forming operations; and wherein the gravel packing conduit is isolated from direct fluid communication with a downstream flow path (510, 610, 810); a transport conduit (508, 608, 708, 808) in fluid communication with the upstream manifold and in fluid communication with the downstream flow path; and a leak-off conduit (506, 606, 706, 806); wherein the leak-off conduit is in at least partially restricted fluid communication with the upstream manifold; wherein the leak-off conduit is in fluid communication with the downstream flow path in a region longitudinally spaced from the upstream manifold; and wherein the leak-off conduit is in fluid communication with the annulus through permeable media (518, 618, 818) adapted to retain particles while communicating fluids providing fluid leak-off from the annulus during the isolation forming operations.