Cementing slurry and method of designing a formulation

• US 6,153,562 A
• Filed: 10/03/1997
• Issued: 11/28/2000
• Est. Priority Date: 09/30/1996
• Status: Expired due to Term

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Villar, John, Baret, Jean-Francois
• Primary Examiner(s): TUCKER, PHILIP C
• Application Number:
  US08/943,565
• Time in Patent Office: 1,152 Days
• Field of Search: 507/269, 507/906, 106/816, 166/285
• US Class Current: 507/269
• CPC Class Codes: C04B 20/0076 characterised by the grain distribution
• CPC Class Codes: C04B 2111/00198 Characterisation or quantities of the compositions or their ingredients expressed as mathematical formulae or equations
• CPC Class Codes: C09K 8/46 containing inorganic binders, e.g. Portland cement
• CPC Class Codes: E21B 33/13 Methods or devices for cementing, for plugging holes, crevices or the like
• CPC Class Codes: Y10S 507/906 Solid inorganic additive in defined physical form

Abstract

The present invention provides a cementing composition for an oil or analogous well, essentially constituted by a solid fraction suspended in a liquid medium. The solid fraction is constituted by a coarse fraction with a packing volume fraction Φ₁ which, according to the invention, is maximised, and a fines fraction x with a packing volume fraction Φ₂ which is less than or equal to the volume fraction x₀ such that ##EQU1## The invention also provides a method of maximising the value of Φ₁. The invention can minimise fluid loss whatever the materials selected for a cementing composition.

Claims

1. A well cement composition for use in performing cementing operations in a subterranean zone comprising a solid fraction of particles suspended in a liquid medium, the solid fraction consisting essentially of a coarse fraction and a fines fraction composed of fines particles having an average diameter less than 1 μ

m, the coarse fraction being comprised of the solid particles in the liquid medium other than the fines particles, the packing volume fraction Φ

₁ of the coarse fraction being greater than 0.8, and the solid volume fraction x of the fines particles being less than or equal to the volume fraction x₀ such that ##EQU5## in which Φ

₂ is the packing volume fraction of the species constituted solely by the fines particles.

2. The cement composition of claim 1 in which the fines particles composing the fines fraction have an average diameter which is less than 0.5μ

.

3. The composition of claim 2 in which the packing volume fraction Φ

₁ is greater than 0.90.

4. The composition of claim 2 in which the solid particles in the coarse fraction comprise cement particles.

5. The composition of claim 3 in which the solid particles in the coarse fraction comprise cement particles.

6. A well cement composition for use in performing cementing operations in a subterranean zone prepared by suspending solid particles in a liquid medium to form a solid fraction in the liquid medium, the solid fraction consisting essentially of a coarse fraction and a fines fraction composed of fines particles having an average diameter less than 1μ

, the coarse fraction being comprised of the solid particles in the liquid medium other than the fines particles, the packing volume fraction Φ

₁ of the coarse fraction being greater than 0.8, and the solid volume fraction x of the fines particles being less than or equal to the volume fraction x₀ which equals ##EQU6## in which Φ

₂ is the packing volume fraction of the fines particles.

7. The cement composition of claim 6 in which the fines particles composing the fines fraction have an average diameter which is less than 0.5μ

.

8. The composition of claim 7 in which the packing volume Φ

₁ is greater than 0.90.

9. The composition of claim 7 in which the solid particles in the coarse fraction comprise cement particles.

10. The composition of claim 8 in which the solid particles in the coarse fraction comprise cement particles.