Compositions and processes for downhole cementing operations

Abstract

The present invention relates to methods of cementing, for example, an oil or gas well. The method may involve pumping a suspension of a filler mixture and at least about 5 weight percent of a thermosetting resin based on the total weight of resin and filler mixture. Advantages may include superior properties and reliability as compared to conventional cementing operations often involving Portland cement.

1 . A suspension comprising:
 (1) from about 15 to about 25 weight percent based on the total weight of the suspension of a first component selected from the group consisting of calcium carbonate, talc, silica, and mixtures thereof wherein the first component has an average particle size distribution of from about 0.5 microns to about 100 microns based on laser scattering;   (2) from about 30 to about 70 weight percent based on the total weight of the suspension of a second component selected from the group consisting of crushed rock, gravel, sand and mixtures thereof wherein the second component has an average particle size distribution of from about 50 microns to about 600 microns based on laser scattering;   (3) from about 25 to about 45 weight percent based on the total weight of the suspension of a thermosetting resin selected from a polyester resin, a vinyl ester resin, and mixtures thereof; and   (4) a catalyst capable of causing the suspension to gel and cure and wherein said gel time is from about 2 to about 10 hours;   wherein the uncured suspension has a pumpability of from about 10 to about 120 Bearden units and wherein the cured composition is characterized by a ratio of tensile strength to compressive strength of at least about 10% wherein the tensile strength is measured according to ASTM C1273 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity and the compression strength is measured according to ASTM 873 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity.   
     
     
         2 . The suspension of  claim 1  wherein the resin has a viscosity of from about 100 to about 5000 centipoise as measured on a Brookfield viscometer at 60 rpm/60 seconds at 25° C. 
     
     
         3 . The suspension of  claim 1  wherein the catalyst is selected from the group consisting of peroxides, amines, anhydrides, phenolics, halides, oxides, and mixtures thereof. 
     
     
         4 . The suspension of  claim 1  wherein the cured composition comprises three or more or more of the following characteristics:
 (a) a tensile strength of at least about 300 psi according to ASTM C1273 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity; 
 (b) a compression strength of at least about 1500 psi according to ASTM C873 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity; 
 (c) a flex strength of at least about 500 psi according to ASTM C873 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity; 
 (d) a fracture toughness of at least about 0.3 Mpa root meter according to ASTM C1421; 
 (e) a ratio of tensile strength to compressive strength of at least about 10% wherein the tensile strength is measured according to ASTM C1273 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity and the compression strength is measured according to ASTM 873 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity; and 
 (f) a flex fatigue resistance such that the cured composition can be subjected to a stress of 50% of the cured composition's ultimate failure strength for at least 1000 cycles without breaking. 
 
     
     
         5 . A method of cementing a subterranean formation comprising the step of pumping a suspension comprising:
 (1) from about 15 to about 25 weight percent based on the total weight of the suspension of a first component selected from the group consisting of calcium carbonate, talc, silica, and mixtures thereof;   (2) from about 30 to about 70 weight percent based on the total weight of the suspension of a second component selected from the group consisting of crushed rock, gravel, sand and mixtures thereof;   (3) from about 20 to about 40 weight percent based on the total weight of the suspension of a thermosetting resin; and   (4) a catalyst capable causing the suspension to cure;   wherein the cured composition is characterized by a ratio of tensile strength to compressive strength of at least about 10% wherein the tensile strength is measured according to ASTM C1273 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity and the compression strength is measured according to ASTM 873 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity.   
     
     
         6 . The method of  claim 5  wherein the thermosetting resin is selected from the group consisting of an epoxy resin, a polyester resin, a vinyl ester resin, a polyurethane resin, a carboxylic based resin, a phenolic based resin, a cross-linked thermoplastic resin, an epoxy novolac, a cellulose based resin, and mixtures thereof. 
     
     
         7 . The method of  claim 5  wherein the thermosetting resin is selected from the group consisting of a polyester resin, a vinyl ester resin, and mixtures thereof 
     
     
         8 . The method of  claim 5  wherein the first component has a particle size distribution of from about 0.5 microns to about 100 microns based on laser scattering. 
     
     
         9 . A method of cementing a subterranean formation comprising the step of pumping a suspension comprising:
 (1) from about 15 to about 25 weight percent based on the total weight of the suspension of a first component selected from the group consisting of calcium carbonate, talc, silica, and mixtures thereof;   (2) from about 30 to about 70 weight percent based on the total weight of the suspension of a second component selected from the group consisting of crushed rock, gravel, sand and mixtures thereof;   (3) from about 10 to about 25 weight percent based on the total weight of the suspension of a thermosetting resin; and   (4) a catalyst capable causing the suspension to cure;   wherein the cured composition is characterized by a ratio of tensile strength to compressive strength of at least about 10% wherein the tensile strength is measured according to ASTM C1273 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity and the compression strength is measured according to ASTM 873 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity.   
     
     
         10 . The method of  claim 9  wherein the thermosetting resin is selected from the group consisting of an epoxy resin, a polyester resin, a vinyl ester resin, a polyurethane resin, a carboxylic based resin, a phenolic based resin, a cross-linked thermoplastic resin, an epoxy novolac, a cellulose based resin, and mixtures thereof. 
     
     
         11 . The method of  claim 9  wherein the thermosetting resin is selected from the group consisting of a polyester resin, a vinyl ester resin, and mixtures thereof 
     
     
         12 . The method of  claim 9  wherein the first component has a particle size distribution of from about 0.5 microns to about 100 microns based on laser scattering. 
     
     
         13 . The method of  claim 9  wherein the catalyst is mixed with the suspension prior to, simultaneously with, or subsequent to pumping. 
     
     
         14 . The method of  claim 9  wherein the catalyst is mixed with the suspension prior to pumping. 
     
     
         15 . The method of  claim 9 , further comprising the step of drilling the well and running a casing, wherein the step of cementing applies to cement the casing. 
     
     
         16 . The method of  claim 9  wherein the suspension comprises substantially no hexavalent chromium compounds. 
     
     
         17 . The method of  claim 9  wherein the suspension comprises substantially no water.