Method Of Creating A Composite Cement With Enhanced Properties For Use In Oil And Gas Wells

Abstract

This invention relates to using a unique blend of components of a composite cement and subjecting them to a rotary mill process using variably sized and shaped media to reduce the blends' particle size. The invention is novel in that it mills the blended materials together to achieve reduced particle size, increased particle surface area, higher compressive strength and lower permeability. In one embodiment, the invention combines fly ash or other pozzolan material with a cement of any type at varying rations between 1% and 99%. In a further embodiment the invention combines fly ash or other pozzolan material at 60% with a cement of any type at 40%.

Claims

1. A method for creating a rotary milled composite cement mixture suitable for use in oil in gas wells comprising: rotary milling a composite cement mixture comprised of, 40% of cement; 60% of fly ash; wherein the rotary milled composite cement mixture has: a maximum particle size of 25 microns; a mean particle size of less than 12 microns; and an average particle surface area of at least 14,500 cm.sup.2/g.

2. The method of claim 1, further comprising hydrating the rotary milled composite cement mixture to a density of 12 pounds per gallon and having a compressive strength of more than 1,000 pounds per square inch.

3. The method of claim 1 further comprising hydrating the rotary milled composite cement mixture to a density of 13.8 pounds per gallon and having a compressive strength of more than 2,000 pounds per square inch.

4. The method of claim 1, further comprising hydrating the rotary milled composite cement mixture to a density of 16 pounds per gallon and having a compressive strength of more than 4,000 pounds per square inch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:

[0023] FIG. 1 is a chart showing a comparison of the mean particle size of a composite cement of the prior art with the mean particle size of a rotary milled composite cement of the invention.

[0024] FIG. 2 is a chart showing a comparison of the average particle surface area of a composite cement of the prior art with a rotary milled composite cement of the invention.

DETAILED DESCRIPTION

[0025] The following description provides details with reference to the accompanying drawings. It should be understood that the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0026] Referring to FIG. 1, mean particle size results were obtained using a Beckman Coulter LS Particle Size Analyzer. The procedure used in obtaining the data was a standard procedure well known to those of skill in the art. With respect to rotary milled composite cements incorporating the invention the mean particle sizes shown were 9.444, 7.880, 3.088, and 2.657 m, respectively, and median particle sizes were 7.618, 5.895, 2.396, and 2.122 m, respectively. On the other hand, an exemplary cement incorporated in the prior art showed a mean particle size of 48.78 m and a median particle size of 26.37 m.

[0027] Referring to FIG. 2, average particle surface area measurements were made using Coulter LS Particle Size Analyzer. The procedure used in obtaining the data was a standard procedure well known to those of skill in the art. With respect to rotary milled cements incorporating the invention, the specific surface area was 18,971 cm.sup.2/g, 21,669 cm2/g, 15,316 cm2/g, and 16,032 cm2/g. On the other hand, an exemplary cement incorporated in the prior art exhibited a specific surface area of 8,957 cm2/g.