1. A method of servicing a wellbore comprising:
(a) preparing a nonaqueous storable cementitious composition;
(b) mixing said composition with an aqueous fluid; and
(c) placing said composition into a wellbore,
wherein the nonaqueous storable cement composition comprises cement, a suspension fluid, a dehydrating agent, an oil wetting surfactant, and a suspension aid, and
wherein the dehydrating agent is a high surface area silica, a zeolitic material, a molecular sieve, a cementitious material, or combinations thereof.
2. The method of claim 1 wherein the suspension fluid is a nonaqueous solvent with a flash point of greater than or equal to about 140\xb0 F.
3. The method of claim 1 wherein the dehydrating agent is a material capable of reducing the water content of a nonaqueous fluid to less than about 5% and is present in an amount of equal to or less than about 25% by weight of the nonaqueous fluid.
4. The method of claim 3 wherein the dehydrating agent is present in an amount from about 5% to about 20% by weight of the nonaqueous fluid.
5. The method of claim 1 wherein the oil wetting surfactant has a hydrophilic-lipophilic balance of less than or equal to 7.0.
6. The method of claim 1 wherein the suspension aid is a polymer, a homopolymer, a copolymer, an elastomer, a polyolefin grafted with polar monomers, or combinations thereof.
7. The method of claim 1 wherein the suspension aid is a polyolefin grafted with maleic anhydride.
8. The method of claim 1 further comprising a viscosifying agent.
9. The method of claim 8 wherein the viscosifying agent comprises an elastomer, a dissolved organic polymer, an organophosphateiron salt combination, a fatty acid and aluminum salt combination, or combinations thereof.
10. The method of claim 9 wherein the elastomer comprises a polyolefin grafted with polar monomers.
11. The method of claim 1 wherein the suspension aid comprises a polymerized diene.
12. The method of claim 1 wherein the suspension fluid comprises an aliphatic hydrocarbon, an oxygenated solvent, or combinations thereof in an amount of at least about 5% by total weight of the nonaqueous storable cementitious composition.
13. The method of claim 1 wherein the cement comprises a hydraulic cement in an amount of at least about 80% by weight of the composition.
14. The method of claim 1 wherein the oil wetting surfactant comprises a nonylphenylethoxylate with less than 5 moles of ethylene oxide, a fatty acid, a salt of a fatty acid, a sorbitan monolaurate, a propylene glycol monostearate, a sorbitan distearate, or combinations thereof.
15. The method of claim 1 wherein the oil wetting surfactant is present in an amount from about 0.1% to about 10% by weight of the suspension fluid.
16. A method of cementing comprising:
(a) preparing a mixture of cement, a suspension fluid, a dehydrating agent, a first surfactant, and a suspension aid;
(b) adding an aqueous solution and a second surfactant to said mixture;
(c) placing the mixture downhole; and
(d) allowing the cement to set,
wherein the first surfactant has a hydrophilic-lipophilic balance less than or equal to 7, and wherein the suspension aid is an elastomer comprising polar monomers.
17. The method of claim 16 wherein the suspension fluid is a nonaqueous fluid having a flash point of equal to or greater than about 140\xb0 F.
18. The method of claim 16 wherein the dehydrating agent is a material capable of reducing the water content of a nonaqueous fluid to less than about 5% and is present in an amount of equal to or less than about 25% by weight of the nonaqueous fluid.
19. The method of claim 16 wherein the dehydrating agent is contacted with the suspension fluid prior to the addition of other slurry components.
20. The method of claim 16 further comprising a viscosifying agent.
21. The method of claim 16 wherein the second surfactant has a hydrophilic-lipophilic balance of greater than or equal to about 10.
22. The method of claim 16 wherein the mixture comprises at least about 5 weight percent suspension fluid, from about 1 weight percent to about 25 weight percent dehydrating agent, from about 0.1 weight percent to about 10 weight percent first surfactant, and from about 0.05 weight percent to about 10 weight percent suspension aid.
23. The method of claim 16 wherein the mixture comprises at least about 10 weight percent suspension fluid, from about 10 weight percent to about 15 weight percent dehydrating agent, from about 0.5 weight percent to about 4 weight percent first surfactant, and from about 0.1 weight percent to about 5 weight percent suspension aid.
24. The method of claim 16 wherein the suspension fluid comprises an aliphatic hydrocarbon, an oxygenated solvent, or combinations thereof in an amount of at least about 5% by total weight of the nonaqueous storable cementitious composition.
25. The method of claim 16 wherein the cement comprises a hydraulic cement in an amount of at least about 80% by weight of the composition.
26. The method of claim 16 wherein the first surfactant comprises a nonylphenylethoxylate with less than 5 moles of ethylene oxide, a fatty acid, a salt of a fatty acid, a sorbitan monolaurate, a propylene glycol monostearate, a sorbitan distearate, or combinations thereof.
27. A method of cementing comprising:
(a) preparing a mixture of cement, a suspension fluid, a dehydrating agent, a first surfactant, and a suspension aid;
(b) adding an aqueous solution and a second surfactant to said mixture;
(c) placing the mixture downhole; and
(d) allowing the cement to set,
wherein the first surfactant has a hydrophilic-lipophilic balance less than or equal to 7 and wherein the dehydrating agent is a high surface area silica, a zeolitic material, a molecular sieve, a cementitious material or combinations thereof.
28. A method of cementing comprising:
(a) preparing a mixture of cement, a suspension fluid, a dehydrating agent, a first surfactant, and a suspension aid;
(b) adding an aqueous solution and a second surfactant to said mixture;
(c) placing the mixture downhole; and
(d) allowing the cement to set,
wherein the first surfactant has a hydrophilic-lipophilic balance less than or equal to 7 and wherein the suspension aid is an elastomer grafted with maleic anhydride.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A diagnostic system for a discrete variable valve lift system of an internal combustion engine, comprising:
a Fast Fourier Transform (FFT) module that generates a frequency content signal based on a FFT method and a valve impact sensor signal; and
a malfunction module that selectively diagnoses a malfunction of a discrete variable valve lift system based on the frequency content signal.
2. The diagnostic system of claim 1 further comprising an analog to digital (AD) converter module that converts the valve sensor signal from an analog signal to a digital signal and wherein the FFT module generates the frequency content signal based on the digital signal.
3. The diagnostic system of claim 1 further comprising a background noise filter module that filters the frequency content signal based on a maximum threshold and wherein the malfunction module selectively diagnoses the malfunction based on the filtered frequency content signal.
4. The diagnostic system of claim 3 wherein the background noise filter module filters the frequency content signal based on a minimum threshold.
5. The diagnostic system of claim 4 wherein the minimum and the maximum threshold values are determined based on engine speed.
6. The diagnostic system of claim 1 wherein the malfunction module sets a malfunction signal based on a frequency range.
7. The diagnostic system of claim 6 wherein the frequency range is based on engine speed.
8. The diagnostic system of claim 1 wherein the valve sensor signal indicates closing events associated with at lest one of a high-lift valve lift profile and a low-lift valve lift profile.
9. The diagnostic system of claim 1 wherein the malfunction module selectively diagnoses a malfunction based on a commanded valve lift schedule of the internal combustion engine.
10. The diagnostic system of claim 1 further comprising a piezoelectric device that generates an impact signal based on mechanical impact load on a valve seat.
11. The diagnostic system of claim 10 wherein the piezoelectric device is a knock sensor that outputs a knock signal indicating a force of impact on a valve seating caused by valves during valve closing events and wherein the sensor signal is the knock signal.
12. The diagnostic system of claim 1 wherein the malfunction module selectively diagnoses a malfunction of a switchable roller finger follower of the variable valve lift system.
13. A method of diagnosing a discrete variable valve lift (DVVL) system of an internal combustion engine, comprising:
receiving an impact signal indicating an impact of a valve closing event,
performing a FFT analysis on the valve signal to generate a frequency signature signal; and
diagnosing a malfunction of the DWL system based on the frequency signature signal.
14. The method of claim 13 further comprising converting the valve signal from an analog signal to a digital signal and wherein the performing a FFT analysis is based on the digital signal.
15. The method of claim 13 further comprising filtering the frequency signature signal based on a maximum threshold.
16. The method of claim 13 further comprising filtering the frequency signature signal based on a minimum threshold.
17. The method of claim 13 wherein the diagnosing a malfunction comprises comparing the frequency signature signal to a frequency range.
18. The method of claim 17 further comprising setting a malfunction code when the frequency signature signal is outside of the threshold frequency range.
19. The method of claim 13 wherein the receiving further comprises receiving an impact signal generated by a piezoelectric device.
20. The method of claim 19 wherein the piezoelectric device is a knock sensor.