An
artificial lift system is disclosed for removing
wellbore fluids from directional or horizontal wellbores. The
artificial lift system incorporates a dual tubing arrangement in which each string contains (respectively) a downhole pumping
system or a
gas lift system. In one string, a
gas lift system, preferably intermittent, is utilized to lift reservoir fluids from below a packer
assembly to above a packer
assembly. This same tubing string is sealingly engaged to the packer and also contains a concentric inner tubing string which extends through and below the packer into the deviated well bore section. This concentric tubing arrangement provides a conduit for the injection gas and also a conduit for the return of commingled reservoir fluids and injection gas where the commingled fluids exit into the annular void between the dual tubing arrangement and the casing, located above the packer. The second tubing string, which is not sealingly engaged to the packer, contains a downhole pump placed above the
exit point of the commingled fluids into the annulus. Because these liquids are trapped above the packer, each time the
gas lift system cycles, they accumulate over time and rise above the downhole pump, which pumps the liquids to the surface. In an alternate embodiment of the invention, a plurality of tubing string arrangements are utilized A plurality of tubing string arrangements are sealingly engaged to a packer and operatively connected to a concentric tubing string that extends into the deviated section of the
wellbore. A gas
lift system, preferably intermittent, is utilized to lift reservoir fluids from below the packer to above the packer. This concentric tubing arrangement provides a conduit for the injection gas and also a conduit for the return of commingled reservoir fluids and injection gas. The commingled fluids exit through a perforated sub in one of the tubing strings above the packer and enter into the annular void between the dual tubing arrangement and the casing. A standing valve is located in the second tubing string below the perforated sub, which effectively trap the liquids in the annulus above the packer. Each time the gas
lift system cycles, these liquids accumulate over time and rise above the downhole pump, which pumps the liquids to the surface.