Method for improving sustained solids-free production from heavy oil reservoirs

Claim 1

A method for producing viscous substantially solids-free hydrocarbonaceous fluids from an unconsolidated or loosely consolidated formation or reservoir comprising: (a) drilling into said reservoir first and second spaced apart wells into a lower productive interval of said formation; (b) perforating both wells in the lower productive interval; (c) fracturing hydraulically said wells at said productive interval with a viscous fracturing fluid containing a proppant therein so as to prop a created fracture and form a fines screen; (d) injecting a pre-determined volume of steam into said first well in an amount sufficient to soften said viscous fluid and lower the viscosity of said fluid adjacent a fracture face; (e) producing the first well at a rate sufficient to allow formation fines to build up on a fracture face communicating with said first well thereby resulting in a filter screen sufficient to substantially remove formation fines from the hydrocarbonaceous fluids; (f) shutting in said first well while injecting steam in a predetermined amount in said second well; (g) shutting in the second well and thereafter producing hydrocarbonaceous fluids from said second well at a rate sufficient to allow formation fines to build up on a fracture face communicating with said second well which results in a filter screen sufficient to remove formation fines from produced hydrocarbonaceous fluids; (h) injecting a second volume of steam into the second well and producing a substantially solids-free hydrocarbonaceous fluid from the first well; (i) shutting in the second well and injecting another volume of steam into the first well; (j) opening the second well and producing to the surface substantially solids-free hydrocarbonaceous fluids of reduced viscosity; (k) shutting in both wells and isolating the lower perforated interval by placing production packers with knock-out plugs therein in both wells; (l) perforating both wells at an upper productive interval of said formation so as to enable fluid communication between the first and second wells; (m) repeating steps (c) through (k) at the upper interval of said formation; (n) thereafter continuing steam injection into the first well until steam breaks through into the second well at the upper interval; (o) shutting in both wells and running in production strings through said packers so as to establish fluid communication between said wells at both intervals; and (p) circulating steam down both wells into the upper interval via said perforations and an annulus formed by said production string with each well thereby forming a "heat chest" which generates heat into the lower interval while producing hydrocarbonaceous fluids from said lower interval via said production string.

Claim 2

A method for producing viscous substantially solids-free hydrocarbonaceous fluids from an unconsolidated or loosely consolidated formation or reservoir comprising: (a) drilling into said reservoir first and second spaced apart wells into a lower productive interval of said formation; (b) perforating both wells in the lower productive interval; (c) fracturing hydraulically said wells at said productive interval with a viscous fracturing fluid containing a proppant therein so as to prop a created fracture and form a fines screen; (d) injecting a pre-determined volume of steam into said first well in an amount sufficient to soften said viscous fluid and lower the viscosity of said fluid adjacent a fracture face; (e) producing the first well at a rate sufficient to allow formation fines to build up on a fracture face communicating with said first well thereby resulting in a filter screen sufficient to substantially remove formation fines from the hydrocarbonaceous fluids; (f) shutting in said first well while injecting steam in a predetermined amount in said second well; (g) shutting in the second well and thereafter producing hydrocarbonaceous fluids from said second well at a rate sufficient to allow formation fines to build up on a fracture face communicating with said second well which results in a filter screen sufficient to remove formation fines from produced hydrocarbonaceous fluids; (h) injecting a second volume of steam into the second well and producing a substantially solids-free hydrocarbonaceous fluid from the first well; (i) shutting in the second well and injecting another volume of steam into the first well; (j) opening the second well and producing to the surface substantially solids-free hydrocarbonaceous fluids of reduced viscosity; (k) shutting in both wells and isolating the lower perforated interval by placing production packers with knock-out plugs therein in both wells; (l) perforating both wells at an upper productive interval of said formation so as to enable fluid communication between the first and second wells; (m) repeating steps (c) through (k) at the upper interval of said formation; (n) thereafter continuing steam injection into the first well until steam breaks through into the second well at the upper interval; (o) shutting in both wells and running in production strings through said packers so as to establish fluid communication between said wells at both intervals; and (p) circulating steam down both wells into the upper interval via said perforations and an annulus formed by said production string with each well thereby forming a "heat chest" which generates heat into the lower interval while producing hydrocarbonaceous fluids from said lower interval via said production string.