High temperature well cementing with low grade blast furnace slag

• US 5,379,840 A
• Filed: 08/19/1993
• Issued: 01/10/1995
• Est. Priority Date: 08/19/1993
• Status: Expired due to Term

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Hale, Arthur H., Cowan, Kenneth M.
• Primary Examiner(s): Suchfield, George A.
• Application Number:
  US08/109,289
• Time in Patent Office: 509 Days
• Field of Search: 166/292, 166/293, 175/65, 106/789, 106/790, 106/791, 507/140
• US Class Current: 166/292
• CPC Class Codes: C04B 18/049 Wastes from oil or other wells, e.g. drilling mud
• CPC Class Codes: C04B 22/064 of the alkaline-earth metals
• CPC Class Codes: C04B 28/08 Slag cements
• CPC Class Codes: C09K 8/46 containing inorganic binders, e.g. Portland cement
• CPC Class Codes: E21B 33/14 for cementing casings into boreholes
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

Drilling fluid is solidified by the incorporation therein of low grade blast furnace slag. In a preferred embodiment lime is also incorporated into said drilling fluid and/or said drilling fluid is a lime drilling fluid. Thus, there is provided a cementitious composition comprising drilling fluid, low grade blast furnace slag and, generally, lime. Also provided is a drilling and cementing process wherein a cementitious slurry comprising low grade blast furnace slag is introduced into a wellbore to cement a casing or liner.

Claims

1. A method of drilling and cementing comprising:

drilling a borehole with a drill string utilizing a drilling fluid, thus producing a used drilling fluid;

removing said drill string and disposing a pipe within said borehole, a portion of said used drilling fluid being disposed in said pipe and in an annulus surrounding said pipe;

combining ingredients comprising blast furnace slag having a slag activity index of less than 100 and water to produce a cementitious slurry;

introducing said cementitious slurry into said pipe; and

displacing said cementitious slurry into said annulus wherein said cementitious slurry encounters a temperature in the range of 150°

-250°

F.

2. A method of drilling and cementing comprising:

drilling a borehole with a drill string utilizing a drilling fluid, thus producing a used drilling fluid;

removing said drill string and disposing a pipe within said borehole, a portion of said used drilling fluid being disposed in said pipe and in an annulus surrounding said pipe;

combining ingredients comprising blast furnace slag having a slag activity index of less than 100 and water to produce a cementitious slurry;

introducing said cementitious slurry into said pipe; and

displacing said cementitious slurry into said annulus wherein said cementitious slurry encounters a temperature within the range of 150°

-700°

F. and wherein said blast furnace slag has a particle size such that it exhibits a Blaine specific surface area within the range of 4000-9000 cm² /g.

3. A method of drilling and cementing comprising:

drilling a borehole with a drill string utilizing a drilling fluid, thus producing a used drilling fluid;

removing said drill string and disposing a pipe within said borehole, a portion of said used drilling fluid being disposed in said pipe and in an annulus surrounding said pipe;

combining ingredients comprising blast furnace slag having a slag activity index of less than 100 and water to produce a cementitious slurry;

introducing said cementitious slurry into said pipe; and

displacing said cementitious slurry into said annulus wherein said cementitious slurry encounters a temperature of greater than 250°

F.