Enhanced oil recovery apparatus and method

Apparatus for heating hydrocarbons in an underground reservoir and facilitating flow of the hydrocarbons, comprising, in combination:

• (a) flow channel means disposable in a reservoir of hydrocarbons for forming a flow path for a working fluid;
• and
• (b) heating means associated with the flow channel means for heating the working fluid prior to discharging the heated working fluid from the flow path and into a reservoir of hydrocarbons to be heated, the flow channel means including, in combination:
• a housing having an exterior and defining a hollow chamber;
• and conduit means arranged in the chamber of the housing and communicating with the exterior of the housing for forming the flow path, the conduit means including a fluid inlet to the chamber, a restricted fluid flow circuit through the chamber and a fluid outlet from the chamber, the housing being provided with connector means for attaching same to a lower end of a pipe string, the fluid inlet and fluid outlet being respectively located in maximum distally spaced portions of the housing, and the fluid flow circuit of the conduit means forming a tortious path, substantially "S" shaped, between the fluid inlet and fluid outlet and arrangeable relative to an associated pipe string to form three substantially parallel, vertically disposed legs, the heating means including a series electrical resistant heating unit comprising an electrical circuit including a pair of opposed electrodes arranged along and partially forming the flow path of a working fluid, a portion of the electrical circuit between the electrodes being completed through the working fluid, the pair of electrodes being one of a plurality of pairs of opposed electrodes and spaced along the flow path of the working fluid, each of the electrodes of the pairs being electrically connected in series with all of the other electrodes in the electrical circuit.

A method for facilitating the recovery from wells of hydrocarbons having relatively high viscosities, comprising the steps of:

• (a) arranging a heating unit at the bottom of a pipe string in a reservoir of hydrocarbons;
• (b) passing through the heating unit a fluid heat transfer medium;
• (c) heating the fluid as it passes through the heating unit;
• (d) injecting the heated fluid into the reservoir of hydrocarbons for reducing viscisity of the hydrocarbons;
• (e) recovering by conventional techniques the reduced viscosity hydrocarbons;
• the step of heating the fluid including the step of passing the fluid between a plurality of pairs of series connected electrodes and using the fluid as part of an electrical circuit connecting the pairs of electrodes;
• and
• (f) maximizing a resistance in a path through the working fluid between the electrodes in relation to a total resistance of the associated circuit for causing a maximum voltage to occur in the working fluid.