Abstract: Disclosed is a method for recovering hydrocarbons from a hydrocarbon-bearing formation. A wellbore is drilled to penetrate the formation and to extend, preferably substantially horizontally, into the formation for a suitable distance. The well is completed with a slotted or perforated casing means and with dual concentric tubing strings. The tubing strings comprise an inner tubing and a surrounding larger diameter outer tubing. The inner tubing cooperates with the outer tubing to form a first annular space and the outer tubing cooperates with the casing means to form a second annular space. After the wellbore is suitably completed, a heated fluid is circulated within the casing means such that the heated fluid passes through a portion of the first annular space to heat the well and to provide a fluid flow path through both the first and second annular spaces. After the well is suitably heated, a heated fluid is injected into the formation through at least a portion of the second annular space.

Abstract: Disclosed is a method for recovering hydrocarbons from a subterranean formation. A heated fluid is injected into the formation by means of a perforated conduit which is positioned substantially horizontally through the formation to heat hydrocarbons within the formation. After a suitable heating period, injection of heat is terminated to permit fluids including formation hydrocarbons to drain from the formation into the conduit. The drained fluids within the conduit are then heated to a temperature such that at least a portion of the drained fluids are vaporized. These vaporized fluids pass from the perforated conduit and into the formation to further heat formation hydrocarbons. Subsequently, formation fluids of reduced viscosity are recovered from the formation through the perforated conduit.