A method (300, 400) of performing a drill stem test in a wellbore, comprising: running a toolstring in the wellbore that extends from a surface and penetrates a hydrocarbon-bearing formation, the formation including an upper zone depleted or dry of a hydrocarbon fluid and a lower zone containing a hydrocarbon fluid, wherein the toolstring includes a plurality of tools to perform the drill stem test in the wellbore, the tools including: a first packer and a second packer; a first fluid valve and a second fluid valve; and a fluid flow device, wherein the fluid flow device includes a cylindrical housing having a wall defining an internal passageway for an axial fluid flow through the housing, and a plurality of ports extending through the wall to provide a path for a radial fluid flow to exit the internal passageway when the ports are open; positioning the toolstring in the wellbore so that the first packer and the second packer straddle the upper zone, the first fluid valve and the second fluid valve straddle the upper zone, and the fluid flow device is adjacent the upper zone; setting the first packer to create a fluid flow barrier between the upper zone and an annulus of the wellbore surrounding the toolstring; setting the second packer to create a fluid flow barrier between the upper zone and the lower zone; closing the first fluid valve to prevent a fluid flow through the toolstring to the surface; opening the second fluid valve and the ports of the fluid flow device to create a closed path for the hydrocarbon fluid to flow from the lower zone and into the upper zone; and perforating the lower zone, wherein the toolstring is operated in a plurality of modes during the drill stem test, including a pre-perforation mode in which status of the tools is verified, a fluid flow mode in which fluid flows from the lower zone into the upper zone, and a build-up mode in which fluid pressure in the wellbore is built up. running a toolstring in the wellbore that extends from a surface and penetrates a hydrocarbon-bearing formation, the formation including an upper zone depleted or dry of a hydrocarbon fluid and a lower zone containing a hydrocarbon fluid, wherein the toolstring includes a plurality of tools to perform the drill stem test in the wellbore, the tools including: a first packer and a second packer; a first fluid valve and a second fluid valve; and a fluid flow device, wherein the fluid flow device includes a cylindrical housing having a wall defining an internal passageway for an axial fluid flow through the housing, and a plurality of ports extending through the wall to provide a path for a radial fluid flow to exit the internal passageway when the ports are open; a first packer and a second packer; a first fluid valve and a second fluid valve; and a fluid flow device, wherein the fluid flow device includes a cylindrical housing having a wall defining an internal passageway for an axial fluid flow through the housing, and a plurality of ports extending through the wall to provide a path for a radial fluid flow to exit the internal passageway when the ports are open; positioning the toolstring in the wellbore so that the first packer and the second packer straddle the upper zone, the first fluid valve and the second fluid valve straddle the upper zone, and the fluid flow device is adjacent the upper zone; setting the first packer to create a fluid flow barrier between the upper zone and an annulus of the wellbore surrounding the toolstring; setting the second packer to create a fluid flow barrier between the upper zone and the lower zone; closing the first fluid valve to prevent a fluid flow through the toolstring to the surface; opening the second fluid valve and the ports of the fluid flow device to create a closed path for the hydrocarbon fluid to flow from the lower zone and into the upper zone; and perforating the lower zone, wherein the toolstring is operated in a plurality of modes during the drill stem test, including a pre-perforation mode in which status of the tools is verified, a fluid flow mode in which fluid flows from the lower zone into the upper zone, and a build-up mode in which fluid pressure in the wellbore is built up.