Disclosed is a gravity-drainage assisted steam flooding process for the recovery of all from thin viscous heavy oil reservoirs using a single horizontal wellbore. Steam is injected through a fully or partially insulated tubing to exit at or near the toe of a long horizontal well penetrating a viscous oil reservoir. Initially, low (10-30%) quality steam is circulated along the well to condition the wellbore and increase the heated radius to about 1 or 2 meters. Oil and reservoir fluids immediately adjacent to the wellbore are produced through the annular space between the insulated tubing string and a slotted liner that surrounds it. After the period of low quality steam circulation, the production outlet is shut in or constrained and steam injection is continued to initiate an active steam chamber zone along a portion of the wellbore. Subsequently, fluid withdrawal is resumed at the production outlet, while the annular liquid level in the vertical section is controlled to maintain a nearly constant pressure at the production outlet. The injection of a higher (50-70% or more) quality steam is continued at a rate similar to or higher than the initial rate to cause the expansion and propagation of the active steam heated volume vertically towards the top of the formation, longitudinally along the horizontal well from the toe towards its heel, and laterally away from the well towards the inter-well boundary with the next row of horizontal well. As steam flows into the reservoir under both gravitational counter current flow and pressure drive, the oil, steam condensate and reservoir fluids heated both conductively and convectively drain towards the slotted liner annulus of the horizontal wellbore and is then pumped to the surface.
A method for recovering viscous oil from a subterranean formation through a wellbore having a horizontal section into the formation. Steam is circulated through the horizontal section to initially heat the formation and to produce fluids to the surface. After the initial heating is complete, production is ceased while the injection of steam is continued to accumulate a slug of steam within and around the horizontal section. The well is then shut-in and the formation is allowed to "soak". Production is then resumed and steam is again continuously injected into the well when oil appears in the produced fluids. This cycle is repeated until the production of oil drops belows an acceptable rate.
A method and assembly for treating a portion (e.g. horizontal) of a wellbore for removing solids and for producing fluids therefrom. The assembly is comprised of dual flowpaths (e.g. tubing strings) extend from the surface into the portion of the wellbore to be treated and produced. A liner is connected on the lower end of the first flowpath while the second flowpath terminates within the upper end of the wellbore portion. A treating fluid is flowed down the first flowpath and through the liner into the wellbore to wash and entrain solids therein. The treating fluid and solids are then circulated back to the surface through the second flowpath. After treatment, the second flowpath is closed and fluids are produced through the liner and to the surface through the first flowpath.
Methods and apparatus for enhanced and improved viscous oil recovery are disclosed. A horizontal well is drilled through the viscous oil formation. A specially designed steam stinger is used to inject steam substantially uniformly into the entire horizontal extent of the well borehole without direct steam impingement on the production liner in the viscous oil formation. Heat from the steam mobilizes and lowers the viscosity of the heavy crude wherein the crude is then produced to the surface via conventional lift arrangements.
A method of achieving a preferential flow distribution in a horizontal well bore. This method consists of the step of positioning in a horizontal wellbore a slotted liner having a plurality of slots which provide a flow area. The slot open flow area of the slotted liner varying along its length in accordance with a selected strategy of flow distribution. The preferred strategy being to create an overbalanced condition in the wellbore which promotes promote a higher flow at the toe portion than at the heel portion.
A combination of SAGD with cogeneration technology for exploiting shallow heavy oil and bitumen reservoirs under primary, secondary and tertiary thermal recovery. Superheated steam is generated by the heat recovery from the exhaust of an above-ground hydrocarbon powered turbine driven electric generator cogeneration plant and is injected through well bores into the hydrocarbon bearing reservoir that is traversed by at least one horizontal producing well bore and one injection well bore to heat the reservoir formation and to induce gravity drainage of the hydrocarbons and allowing their recovery from the horizontal producing well bore. Electrical power that is generated is sold to the electric grid and can be used to offset the fuel costs for the above ground hydrocarbon turbine-driven elector generators.
