Cold fluid hydraulic fracturing process for mineral bearing formations

• US 4,660,643 A
• Filed: 02/13/1986
• Issued: 04/28/1987
• Est. Priority Date: 02/13/1986
• Status: Expired due to Fees

• Current Assignee: Atlantic Richfield Company Incorporated (BP PLC)
• Original Assignee: Atlantic Richfield Company Incorporated (BP PLC)
• Inventors: Perkins, Thomas K.
• Primary Examiner(s): NOVOSAD, STEPHEN
• Application Number:
  US06/829,374
• Time in Patent Office: 439 Days
• Field of Search: 166/308, 166/283, 166/302, 166/281
• US Class Current: 166/283
• CPC Class Codes: E21B 36/001 Cooling arrangements
• CPC Class Codes: E21B 43/26 by forming crevices or fractures
• CPC Class Codes: E21B 43/267 reinforcing fractures by propping

Abstract

A method for hydraulic fracturing a subterranean formation region to control the fracture extent in vertical and horizontal directions characterized by the injection of cold liquid into the formation region to precool the region and reduce the stresses in the formation region so that a hydraulic fracture may be propagated at a lower fluid injection pressure. The shape of the cooled region may be controlled by injection of various quantities of leakoff control agent during injection of the cold liquid and extension of the hydraulic fracture may be carried out simultaneously with the cold liquid flooding or by raising the pressure after the flood front has progressed a desired radial extent from the wellbore. The fracturing operation may be completed by injecting a pad of cold liquid with a high concentration of leakoff control agent to seal the fracture face followed by injection of liquid carrying a sufficient quantity of proppant material to maintain the fracture width and conductivity at the desired level.

Claims

1. A method for hydraulically fracturing a subterranean formation region to stimulate the production of recoverable fluids therefrom comprising the steps of:

providing a wellbore extending into said formation region and means for conducting fluid between said wellbore and said formation region;

injecting a relatively cold liquid into said formation region through said wellbore at a rate which will result in substantial cooling of the formation region below the nominal preinjection temperature of said formation region so as to lower the stresses exerted within the formation region;

increasing the pressure of said cold liquid being injected at a predetermined time after commencing injection of said cold liquid to a value which will initiate a fracture in the cooled portion of said formation region;

injecting a leakoff control agent with said cold liquid in sufficient amounts to provide further flooding of said formation region but to control the shape of the flood front progressing outward from said fracture; and

injecting liquid into said fracture containing a quantity of proppant material for maintaining said fracture in a propped open condition upon release of pressure in said wellbore and said formation region due to said injected liquid.

2. The method set forth in claim 1 wherein:

the step of injecting said leakoff control agent with said cold liquid is carried out during extension of said fracture by increasing the injection rate of said cold liquid.

3. The method set forth in claim 1, including the step of:

injecting cold liquid containing a relatively high concentration of leakoff control agent into said fracture after the formation thereof to seal the faces of said fracture.

4. The method set forth in claim 3 wherein:

the step of injecting liquid containing proppant material into said fracture is carried out after the injection of liquid containing said high concentration of leakoff control agent and while maintaining pressure in said fracture sufficient to prop said fracture open.

5. A method for hydraulically fracturing a subterranean formation region to stimulate the production of recoverable fluids therefrom, comprising the steps of:

providing a wellbore extending into said formation region and means for conducting fluid between said wellbore and said formation regions;

injecting a relatively cold liquid into said formation region through said wellbore at a rate such that the pressure of the fluid being injected into the formation region is sufficient to fracture the formation region as the formation region is cooled below its preinjection temperature, and so that the outer limits of the flooded portion of the formation region are defined by a generally elliptical boundary;

injecting selected amounts of leakoff control agent with said injection liquid to at least partially seal the faces of said fracture to control the ellipticity of the boundaries of said cooled portion of said formation region and increasing the amount of leakoff control agent injected with said injection liquid to reduce the migration of injection fluid generally normally to the planes of said fracture;

sealing the faces of said fracture by injecting liquid having a significantly higher concentration of leakoff control agent; and

injecting fluid at a relatively high rate and with a relatively high concentration of proppant material having a proppant size range sufficient as to maintain the fracture propped open to a predetermined width without significantly reducing fracture conductivity.

6. A method for hydraulically fracturing a subterranean formation region to control the vertical and horizontal extent of the fracture and to stimulate the production of recoverable fluids therefrom comprising the steps of:

providing a wellbore extending into said formation region and means for conducting fluid between said wellbore and said formation region;

injecting a relatively cold liquid into said formation region through said wellbore at a rate which will result in substantial cooling of said formation region below the nominal preinjection temperature of said formation region so as to lower the stresses exerted within said formation region;

increasing the pressure of the cold liquid during injection thereof to initiate a fracture simultaneously with the injection of cold liquid into said formation region so that said fracture is propagated radially outwardly from said wellbore coincident with the reduction in temperature and stresses in the flooded portion of said formation region;

injecting a leakoff control agent with said cold liquid in sufficient amounts to provide further flooding of said formation region but to control the shape of the flood front progressing outward from said fracture; and

injecting liquid into said fracture containing a quantity of proppant material for maintaining said fracture in a propped open condition upon release of pressure in said wellbore and said formation region due to said injected liquid.

7. The method set forth in claim 6, including the step of:

injecting cold liquid containing a relatively high concentration of leakoff control agent into said fracture after the formation thereof to seal the faces of said fracture.