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Publication numberUSRE32742 E
Publication typeGrant
Application numberUS 06/910,290
Publication dateSep 6, 1988
Filing dateSep 17, 1986
Priority dateAug 16, 1979
Fee statusPaid
Also published asCA1140324A1, US4385935
Publication number06910290, 910290, US RE32742 E, US RE32742E, US-E-RE32742, USRE32742 E, USRE32742E
InventorsSigve Skjeldal
Original AssigneeElkem A/S
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of producing light weight cement for use of cementation of oil and gas wells
US RE32742 E
Abstract
A cement slurry of low specific density for cementation of oil-and gas wells is produced by mixing oil-well cement with finely divided emission products comprising amorphous silica dust which has been obtained during the electrothermal preparation of ferrosilicon and/or silicon metal, water, and any desirable dispersion components, the emission products being added in an amount in the range of 1-50% of the total weight of dry material. The emission products can either be mixed with the cement while both components are in the dry state whereupon there is added a sufficient quantity of water in order to obtain a desired specific weight of the slurry or first mixed with water and any other desired dispersion components and this slurry is mixed with the oil-well cement.
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Claims(6)
What is claimed is:
1. The improved method of cementing the space between the interior wall of a well and the exterior wall of an internal tube therein with a low-density pumpable slurry of cement used in oil and gas well exploration which comprises the steps of:
(a) mixing an oil and gas well cement with water and particulate silica formed by precipitating the fumes generated by an electrometallurgical smelting furnace for producing silicon or ferrosilicon, said particulate silica having a surface area from about 18 to about 22 m2 per gram, the proportion of said particulate silica to cement in said slurry being about one part of silica for each two parts of cement;
(b) adjusting the density of said slurry by adding sufficient water to provide a low density pumpable aqueous slurry of not over about 12.6 pounds per gallon; and
(c) pumping said slurry into the space between said tube and interior wall of the well for cementation thereof.
2. The method of claim 1 wherein the particulate silica and cement are mixed in a dry state followed by addition of water to form the low density slurry.
3. The method of claim 1 wherein dispersion components .[.chosen from the group consisting of bentonite, pozzolan, diatomaceous earth, perlite, water glass and gilsonite.]. are added to vary the density of said slurry from about 11.5 to about 15.5 pounds per gallon.
4. The method of claim 1 wherein an aqueous slurry comprising the said silica and water is formed and thereafter the resulting silica slurry is mixed with said oil and gas well cement. .Iadd.
5. The improved method of cementing the space between the interior wall of a well and the exterior wall of an internal tube therein with a low-density pumpable slurry of cement used in oil and gas well exploration which comprises the steps of:
(a) mixing an oil and gas well cement with water and amorphous particulate silica dust formed by precipitating the fumes generated by an electrometallurgical smelting furnace for producing silicon or ferrosilicon, said amorphous particulate silica dust being about 82 to about 95% silica particulate, said silica particulate having a surface area from about 18 to about 22 m2 per gram, and a real density of about 2.2 to about 2.25 gram per cm3, the proportion of said particulate silica dust to cement in said slurry being from about 1 to about 50% of the total weight of the dry material;
(b) adjusting the density of said slurry by adding sufficient water to provide a low density pumpable aqueous slurry of between about 11.5 and about 15.5 pounds per gallon; and
(c) pumping said slurry into the space between said tube and the interior wall of the well for cementation thereof. .Iaddend. .Iadd.
6. The improved method of cementing the space between the interior wall of a well and the exterior wall of an internal tube therein with a low density pumpable cement slurry consisting essentially of: oil and gas well cement; water and amorphous particulate silica dust formed by precipitating the fume generated by an electrometallugical smelting furnace for producing silicon or ferrosilicon, said amorphous particulate silica dust having a surface area from about 18 to about 22 m2 per gram, and a real density of about 2.2 to about 2.25 grams per cm3 ; said improved method comprising the steps of:
(a) mixing said oil and gas well cement with water and said amorphous particulate silica dust, the proportion of said particulate silica dust to cement in said slurry being from about 1 to about 50% of the total weight of dry material;
(b) adjusting the density of said slurry by adding sufficient water to provide a low density, pumpable, aqueous slurry of between about 11.5 and about 15.5 pounds per gallon; and
(c) pumping said slurry into the space between said tube and the interior wall of the well for cementation thereof. .Iaddend. .Iadd.7. The method of claim 6 wherein said amorphous particulate silica dust and cement are mixed in a dry state followed by addition of water to form the low density slurry. .Iaddend. .Iadd.8. The method of claim 6 wherein said amorphous particulate silica dust and water are mixed to form an aqueous slurry and thereafter the resulting aqueous slurry is mixed with said oil and gas well cement. .Iaddend. .Iadd.9. The method of claim 6 wherein a dispersion component is mixed with said oil and gas well cement, water and said amorphous particulate silica dust. .Iaddend.
Description

This is .Iadd.a continuation of application Ser. No. 739,181 filed May 30, 1985, abandoned, which is a reissue of Ser. No. 324,559 filed Nov. 24, 1981 which was .Iaddend.a continuation of application Ser. No. 198,668, filed Oct. 20, 1980, which was a continuation-in-part of application Ser. No. 177,872, filed Aug. 14, 1980, both now abandoned.

The invention relates to a method of producing a cement slurry of low specific weight suitable for use in the cementation of oil-and gas wells. It also relates to the composition of the cement slurry.

In the cementation of oil-or gas wells a cement slurry is pumped into the well through a form pipe. The slurry will gradually fill the empty space between the wall of the pipe and the wall of the well. The specific weight of the cement slurry is of the greatest importance in the process of cementation of the well. For instance, in drilling wells through high pressure zones, a cement slurry with a high specific weight is required in order to resist and control the flowing during the cementation process. However, in drilling wells through low pressure zones, as well as zones in which drilling mud may easily penetrate, it is necessary to utilize a cement slurry with a low specific weight. An object of the invention is to produce a cement slurry of low specific weight which is suitable for the cementation of oil and gas wells.

It is known that the specific weight of a cement slurry can be reduced by increasing the amount of water in the slurry. In order to absorb the increased quantity of water, other materials such as bentonite, pozzolan, diatomaceous earth, perlite, water glass and/or gilsonite are added. Of these materials, bentonite is today most frequently used in cement slurries, and usually employed in concentration constituting from 1-12% of the weight of the cement. By addition of 12% bentonite, one will obtain a specific weight of the slurry of 12.6 lbs./gallons corresponding to 15 kg/dm. When using water glass, pozzolan and diatomaceous earth, the relatively high content of silica in these materials will tend to bind that calcium hydroxide which is formed during the hardening of the cement and transform it to a more insoluble and stable component. Therefore, the employment of these materials will result in a relatively higher strength after hardening than is obtained through the use of bentonite.

It has been discovered that finely divided amorphous silica dust which has been obtained as an emission product during the electrothermal preparation of ferrosilicon and/or silicon metal can be used in the cement slurries for cementation of oil-gas wells.

In the method according to the invention, the amorphous silica dust are mixed with an API (American Petroleum Institute) approved oil-well cement. The amount of amorphous silica dust (obtained as an emission product) which is to be added is in the range of 1-50% by weight of the dry materials.

The emission products comprise amorphous silica in the range of from 82-95% of the total emission product. For example, the amorphous silica particles may comprise at least 82% by weight of SiO2, will have a real density of approximately 2.2-2.5 g/cm2 and will have a specific surface area of 18-22 m2 /g, the particles being substantially spherical, and wherein at least 60% by weight of the particles have a particle size less than 1 micron. It is, of course, well known that variation of these values is readily possible depending upon the parameters of the electrothermal processing.

The amorphous silica dust or the emission products comprising chiefly the amorphous SiO2 can either be mixed in the dry state with the oil well cement to which there is then added a sufficient quantity of water to obtain a slurry having specific densities in the range of 10-16 lbs./gallon corresponding to 1.19-1.91 kg/dm3. As is known, the amount of water can be reduced by the addition of dispersion materials. Of course, other known concrete additives may also be used as desired.

It will be appreciated that it is also possible to produce a slurry of the emission products and any dispersion components and to deliver this product as a slurry to a site where it will be mixed with the oil well cement. The ratio of mixture in this case and the specific weight will remain the same as when the emission products are mixed with the cement in the dry state.

By mixing a ratio of amorphous silica dust/cement of 33:67, there may be obtained specific weights in the range of 11.5-15.5 lbs./gallon corresponding to 1.37-1.85 kg/dm3 and a compressive strength of 3890 psi corresponding to 27.3 kg/cm2 with dispersion components and 440 psi corresponding to 30.93 kg/cm2 without additives. The compressive strength here referred to are obtained after 24 hours at 95 F. corresponding to 35 C. at atmospheric pressure. For instance, the addition of a quantity of water amounting to 92.7% of weight of the mixture will give a specific weight of the slurry of 12.6 lbs/gallon corresponding to 15 kg/dm2. If a higher specific density is desired a dispersion component must be added.

Upon hardening, the above described slurry will provide a tight concrete with few pores and high compression strength. The density is highly important, particularly in offshore operations, in order to prevent the penetration of the oil and gas in one formation into another formation.

Patent Citations
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US4111711 *Jul 18, 1977Sep 5, 1978Societe Europeenne Des Produits RefractairesAlkaline earth mineral and silica or chromium dioxide or titania or zirconia or alumina and a filler
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5149370 *Oct 21, 1991Sep 22, 1992Halliburton CompanyWell cement compositions having improved properties and methods
US5168928 *Aug 15, 1991Dec 8, 1992Halliburton CompanyPreparation and use of gelable silicate solutions in oil field applications
US5327968 *Dec 30, 1992Jul 12, 1994Halliburton CompanyUtilizing drilling fluid in well cementing operations
US5355954 *Nov 2, 1993Oct 18, 1994Halliburton CompanyUtilizing drilling fluid in well cementing operations
US5398758 *Nov 30, 1993Mar 21, 1995Halliburton CompanyUtilizing drilling fluid in well cementing operations
US6344081Apr 25, 2000Feb 5, 2002Glasflo Products, Inc.Concrete composition
US6379456Apr 11, 2000Apr 30, 2002Halliburton Energy Services, Inc.Flow of dry material particles, organic acids, absorbers and blends
US6478869Mar 23, 2001Nov 12, 2002Halliburton Energy Services, Inc.Flow properties of dry cementitious materials
US6494951 *Sep 23, 1999Dec 17, 2002Halliburton Energy Services, Inc.Methods of cementing within subterranean formations penetrated by well bores wherein the flow properties of one or more dry particulate cementitious materials are improved and wherein the materials can be readily conveyed out of storage tanks
US6610139Sep 27, 2002Aug 26, 2003Halliburton Energy Services, Inc.Adsorbing a flow inducing chemical(polar molecule producing organic acids, salts and acid anhydride) on a particulate solid adsorbent material
US6660080Sep 27, 2002Dec 9, 2003Halliburton Energy Services, Inc.Particulate flow enhancing additives
US6699321Oct 24, 2001Mar 2, 2004Glasflo Products, Inc.Comprising e-glass (electric glass, a borosilicate) particles, cement, and glass aggregate; contains recycled glass
US7350573Feb 7, 2005Apr 1, 2008Halliburton Energy Services, Inc.Servicing a wellbore with wellbore fluids comprising perlite
US7559369May 10, 2007Jul 14, 2009Halliubrton Energy Services, Inc.Well treatment composition and methods utilizing nano-particles
US7748453Jan 24, 2008Jul 6, 2010Halliburton Energy Services, Inc.Servicing a wellbore with wellbore fluids comprising perlite
US7784542May 27, 2009Aug 31, 2010Halliburton Energy Services, Inc.Cementing in a subterranean formation by introducing a cement, a nanoparticle free of silica fume, latex, and water into the formation, and allowing the cement composition to set
US7806183Apr 20, 2009Oct 5, 2010Halliburton Energy Services Inc.rilling fluids, completion fluids, stimulation fluids, and well clean-up fluids; comprising cement, water and nano-silica particles; filling space between pipe string and subterranean formation; compressive strength, shear-bond strength, tensile strength; noncracking; mechanical properties
US7892352Apr 20, 2009Feb 22, 2011Halliburton Energy Services. Inc.Well treatment compositions and methods utilizing nano-particles
US8157009Sep 3, 2009Apr 17, 2012Halliburton Energy Services Inc.Cement compositions and associated methods comprising sub-micron calcium carbonate and latex
US8598093Jul 9, 2010Dec 3, 2013Halliburton Energy Services, Inc.Cement compositions comprising latex and a nano-particle
Classifications
U.S. Classification106/812, 116/292, 106/607, 106/698, 106/633, 106/737, 106/631
International ClassificationC09K8/46, C04B18/14, C09K8/42
Cooperative ClassificationC09K8/46, C04B18/146, C04B28/02, C09K8/42
European ClassificationC09K8/42, C04B18/14F, C09K8/46, C04B28/02
Legal Events
DateCodeEventDescription
Sep 2, 1994FPAYFee payment
Year of fee payment: 12
Jan 2, 1991REMIMaintenance fee reminder mailed
Nov 6, 1990FPAYFee payment
Year of fee payment: 8