Low viscosity synthetic cement
View Patent ↗The present invention relates to a synthetic cement that comprises a low viscosity monofunctional monomer, a dicyclopentadienyl moiety having a pendant free radical reactive species, 1,3-butyleneglycol dimethacrylate, unsaturated styrenic block copolymer, and a peroxide curing agent. Additionally it may include weighting agents depending on the circumstances of the well, as is well known to those skilled in the art. Other additional components such as oil based mud, suspending agents, Portland cement, acrylates and methacrylates, retardant curing additives, and clays may optionally be incorporated into the synthetic cement. The synthetic cement is activated by heat, for example, and can be crafted to set within a certain time frame, for example in 4 hours, so that it pumpable for as long as need be, and then be set to seal the well in the manner desired.
1. A synthetic cement compatible with oil based mud for cementing wells, comprising:
i) a vinyl ester, an acrylate, or methacrylate monomer;
ii) a dicyclopentadienyl moiety having an attached moiety susceptible to free radical reaction including acrylate, methacrylate, vinyl, olefinic, allyl, or amide;
iii) an unsaturated styrenic block copolymer; and
iv) a free radical initiator.
2. The synthetic cement of claim 1 , having an initial average solution viscosity of 50 to less than about 1000 cP at 70° F., a compressive strength of ≧1000 psi, a right angle set time of 25 to 400 minutes, and a compressive strength of at least about 400 psi in the presence of at least 20 wt % oil based mud.
3. The synthetic cement of claim 1 , wherein the Young's Modulus is between 800 and 20,000 psi.
4. The synthetic cement of claim 1 , wherein the dicyclopentadienyl moiety contains an acrylate, methacrylate, vinyl or allyl pendant reactive species.
5. The synthetic cement of claim 4 , wherein the dicyclopentadienyl moiety is dicyclopentadienyl methacrylate (C 14 H 18 O 2 ).
6. The synthetic cement of claim 5 , wherein said dicyclopentadienyl methacrylate is present in a range of about 10 to about 80 wt. %.
7. The synthetic cement of claim 1 , wherein said vinyl ester is a derivative of versatic acid with 9-12 carbon atoms.
8. The synthetic cement of claim 1 , wherein said vinyl ester is represented by the formula C 11 H 20 O 2 or C 12 H 22 O 2 .
9. The synthetic cement of claim 1 , wherein said unsaturated styrenic block copolymer has a total average molecular weight of 100,000 to 450,000; a polystyrene content of 27-40 wt. %, a degree of branching of 2-4; up to 80 wt. % diblock content; at least 5 mol % vinyl content; and coupling up to 80%.
10. The synthetic cement of claim 1 , wherein said unsaturated styrenic block copolymer is a linear styrene-butadiene-styrene.
11. The synthetic cement of claim 10 , wherein said unsaturated styrenic block copolymer is in a range of 5 to 45 wt. % of the synthetic cement.
12. The synthetic cement of claim 1 , wherein said unsaturated styrenic block copolymer is styrene- butadiene- styrene, with a polystyrene content of 27 to 40 wt. %.
13. The synthetic cement of claim 1 , further including a weighting agent.
14. The synthetic cement of claim 13 , wherein said weighting agent is employed in an amount such that said fluid and said weighting agent range from about 8 to about 20 lb/gal.
15. The synthetic cement of claim 1 , wherein said vinyl ester, an acrylate, or methacrylate monomer is present in a range of 10 to 80 wt. %.
16. The synthetic cement of claim 1 , wherein said free radical initiator is selected from a linear aliphatic organic peroxide, bisperoxy benzene peroxide, or dicumyl organic peroxide.
17. The synthetic cement of claim 16 , wherein said free radical initiator is in the range of 0.1 to 1.0 wt. % of i+ii+iii.