1. A method of reducing the water permeability of a well bore during the drilling phase, comprising:
providing a polymer comprising:
(i) a monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides, alkyl dimethylammoniumethyl methacrylate halides, and alkyl dimethylammonium propylmethacrylamide halides, wherein the alkyl groups have from about 4 to about 22 carbon atoms; and
(ii) a monomer selected from the group consisting of acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, dimethylaminopropylmethacrylamide, trimethylammoniumethyl methacrylate chloride, methacrylamide and hydroxyethyl acrylate; and
placing the polymer down hole, thereby reducing the water permeability of the well bore.
2. The method of claim 1 wherein the mole ratio of the monomer of (i) to the monomer of (ii) in the polymer is in the range of from about 10:90 to 0.02:99.98.
3. The method of claim 1 wherein the polymer is placed down hole as part of a drilling fluid.
4. The method of claim 3 wherein the drilling fluid is water-based.
5. The method of claim 3 wherein the drilling fluid is oil-based.
6. The method of claim 1 wherein the polymer is placed down hole as part of a pill.
7. The method of claim 6 where the pill comprises an aqueous carrier liquid.
8. The method of claim 7 wherein the aqueous carrier liquid is an aqueous salt solution.
9. The method of claim 8 wherein the salt in the aqueous salt solution is selected from the group consisting of potassium chloride, sodium chloride, ammonium chloride and calcium chloride and is present in the aqueous salt solution in an amount in the range of from about 2% to about 10% by weight of the solution.
10. A drilling fluid additive, comprising:
a polymer comprising:
(i) a monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides, alkyl dimethylammoniumethyl methacrylate halides, and alkyl dimethylammonium propylmethacrylamide halides, wherein the alkyl groups have from about 4 to about 22 carbon atoms; and
(ii) a monomer selected from the group consisting of acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, dimethylaminopropylmethacrylamide, trimethylammoniumethyl methacrylate chloride, methacrylamide and hydroxyethyl acrylate.
11. The composition of claim 10 wherein the mole ratio of the monomer of (i) to the monomer of (ii) in the polymer is in the range of from about 10:90 to 0.02:99.98.
12. A method of reducing the water permeability of a well bore during the drilling phase, comprising:
providing a polymer comprising:
(i) a monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides, alkyl dimethylammoniumethyl methacrylate halides, and alkyl dimethylammonium propylmethacrylamide halides, wherein the alkyl groups have from about 4 to about 22 carbon atoms; and
(ii) a monomer selected from the group consisting of acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, dimethylaminopropylmethacrylamide, trimethylammoniumethyl methacrylate chloride, methacrylamide and hydroxyethyl acrylate, wherein the mole ratio of the monomer of (i) to the monomer of (ii) in the polymer is in the range of from about 10:90 to 0.02:99.98; and placing the polymer down hole, thereby reducing the water permeability of the well bore.
13. The method of claim 12 wherein the polymer is placed down hole as part of a drilling fluid.
14. The method of claim 13 wherein the drilling fluid is water-based.
15. The method of claim 13 wherein the drilling fluid is oil-based.
16. The method of claim 12 wherein the polymer is placed down hole as part of a pill.
17. The method of claim 16 where the pill comprises an aqueous carrier liquid.
18. The method of claim 17 wherein the aqueous carrier liquid is an aqueous salt solution.
19. The method of claim 18 wherein the salt in the aqueous salt solution is selected from the group consisting of potassium chloride, sodium chloride, ammonium chloride and calcium chloride and is present in the aqueous salt solution in an amount in the range offrom about 2% to about 10% by weight of the solution.
20. A method of forming a relative permeability modifying polymer comprising:
polymerizing a hydrophilic monomer to form a homopolymer; and
partially quaternizing the homopolymer with an alkyl halide to form a copolymer.
21. The method of claim 20 wherein the hydrophilic monomer is a tertiary amine.
22. The method of claim 20 wherein the hydrophilic monomer is dimethylaminoethyl methacrylate.
23. The method of claim 22 wherein the alkyl halide comprises C16 alkyl (n-hexadecyl) dimethylammonium ethyl methacrylate bromide.
24. The method of claim 22 wherein the copolymer comprises repeating units of dimethylaminoethyl methacrylate and alkyl-dimethylaminoethyl methacrylate halide.
25. The method of claim 20 wherein the hydrophilic monomer is dimethylaminopropyl methacrylamide.
26. The method of claim 25 wherein the copolymer comprises repeating units of dimethylaminopropyl methacrylamide and alkyl-dimethylaminopropyl methacrylamide halide.
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 method for aligning a stent with a stent support, comprising:
placing a stent support and a stent mounted on the stent support in a vertical position with the stent support’s first support element at a lower position and the stent support’s second support element at an upper position, wherein the lower end of the stent faces a conical portion of the first support element and the upper end of the stent faces a conical portion of the second support element;
obtaining a digital image of the stent support and stent;
analyzing the digital image of the stent support and stent to compute the vertical position of the stent’s upper end;
computing a desired position of the second support element based on the position of the stent’s upper end; and
using a positioning device to move the second support element to the desired position, wherein the movement of the second support element causes the conical portions of the first and second support elements to engage the respective ends of the stent to center the stent around a core element of the stent support and to secure the stent in a longitudinal direction of the stent support.
2. The method of claim 1, further comprising:
the step of obtaining the digital image of the stent support and stent includes using a digital imaging device to obtain the digital image of the stent support and stent.
3. The method of claim 1, further comprising:
computing stent runout after the step of using the positioning device to move the second support element.
4. The method of claim 3, further comprising:
if the computed stent runout is greater than an acceptable limit, lifting the second support element to disengage the second support element from the upper end of the stent.
5. The method of claim 4, further comprising:
after the second support element has been disengaged from the upper end of the stent, repeating the step of obtaining a digital image of the stent support and stent;
repeating the step of analyzing the digital image;
repeating the step of computing a desired position of the second support element; and
repeating the step of using the positioning device to move the second support element to the desired position.
6. The method of claim 1, further comprising:
obtaining a second digital image of the stent support and stent after the step of using the positioning device to move the second support element; and
computing the actual position of the second support element from the second digital image and comparing the actual position of the second support element with the desired position.
7. The method of claim 6, further comprising:
if the difference between the actual and desired positions of the second support element exceeds an acceptable limit, using the positioning device to move the second support element to the desired position.
8. The method of claim 1, further comprising:
re-seating the stent on the conical portion of the first support element before the step of obtaining the digital image of the stent support and the stent.
9. The method of claim 8, wherein the step of re-seating includes vibrating the first support element.
10. The method of claim 8, wherein the step of re-seating includes striking the first support element.
11. The method of claim 8, wherein the step of re-seating includes lifting the stent off the first support element and releasing the stent.
12. The method of claim 8, wherein the step of re-seating includes tapping on the stent.
13. The method of claim 1, further comprising determining the orientation of the stent from the digital image of the stent support and stent.
14. The method of claim 13, wherein the step of determining the orientation of the stent includes examining crown types at least one stent end.
15. The method of claim 1, further comprising determining the type of the stent from the digital image of the stent support and stent.
16. The method of claim 15, further comprising computing the length of the stent and determining the type of the stent based on the length of the stent.
17. The method of claim 15, further comprising computing the number of end crowns at least one of the stent ends and determining the type of the stent based on the number of end crowns.
18. The method of claim 15, further comprising determining the types of end crowns at least one of the stent ends and determining the type of the stent based on the types of end crowns.
19. The method of claim 15, further comprising:
determining the types of end crowns at least one of the stent ends;
computing the length of the stent; and
determining the type of the stent based on the types of end crowns and the length of the stent.
20. The method of claim 1, wherein the digital image includes the entire outer surfaces of the stent ends.
21. The method of claim 20, further comprising determining the orientation of the stent from the digital image of the stent support and stent.
22. The method of claim 21, wherein the step of determining the orientation of the stent includes examining the end crown types at least one stent end.
23. The method of claim 20, further comprising determining the type of the stent from the digital image of the stent support and stent.
24. The method of claim 23, further comprising computing the length of the stent and determining the type of the stent based on the length of the stent.
25. The method of claim 23, further comprising determining the number of end crowns at least one of the stent ends and determining the type of the stent based on the number of end crowns.
26. The method of claim 23, further comprising determining the types of end crowns at least one of the stent ends and determining the type of the stent based on the types of end crowns.
27. The method of claim 23, further comprising:
determining the types of end crowns at least one of the stent ends;
computing the length of the stent; and
determining the type of the stent based on the types of end crowns and the length of the stent.
28. The method of claim 1, further comprising:
supporting a free end of the core element so that the core element and the first support element are substantially coaxial.
29. A device for aligning a stent with a stent support, comprising:
a stent support receptacle for receiving a first support element of a stent support to position the stent support in a vertical position;
a digital imaging device for imaging a stent mounted on the stent support;
a computer connected to the digital imaging device for receiving a digital image of the stent support and the stent mounted thereon, wherein the computer computes the position of an upper end of the stent from the digital image of the stent support and the stent mounted thereon and computes a desired position of a second support element of the stent support based on the position of the stent’s upper end; and
a positioning device for moving the second support element to the desired position.
30. The device of claim 29, further comprising:
a core element support for supporting a free end of a core element of the stent support so that the core element and the first support element are substantially coaxial.