A method for lowering the viscosity of a heavy hydrocarbon in situ in a well formation so as to improve well production wherein the heavy hydrocarbon has an API gravity in the range between 6.degree. and 12.degree. and a dynamic viscosity in the range between 300 and 900 centipoises @ 195.degree. F. comprising lowering the viscosity of a virgin heavy hydrocarbon outside of a well formation wherein said heavy hydrocarbon has an API gravity in the range between 6 and 12 degrees and a dynamic viscosity above 300 centipoises @ 195.degree. F. so as to make pumpable with conventional pumping equipment comprising mixing said hyrdocarbon at a temperature range between 400.degree. and 500.degree. F. with steam and an additive selected.
A method of producing hydrocarbons from a subterranean formation. The method includes the steps of: building an array of at least three horizontal wells; establishing injectivity in the formation; establishing communication between adjacent horizontal sections of wells in the array; injecting a fluid through the horizontal section of an outer well in the array while producing hydrocarbons and associated fluids through the horizontal section of a well immediately adjacent to the outer well; and simultaneously applying the steps of injecting and producing to adjacent remaining pairs of wells in the array so that with respect to any particular well in the array, that is being used for fluid injection, each well in the array immediately adjacent to it is being used for fluid production, and wherein the hydrocarbons and associated fluids are produced at a cumulative rate of production from the entire array that establishes a pressure differential between the wells in the array, and wherein the cumulative rate of fluid production from the array is greater than the cumulative rate of fluid injection through the array.
