Stator compound having an NBIR terpolymer elastomeric base and stators and downhole motors using the same

1. A stator compound including an acrylonitrile butadiene isoprene rubber (NBIR) polymer elastomeric base, wherein the acrylonitrile butadiene isoprene polymer elastomeric base is 100% non-hydrogenated.

2. The stator compound of claim 1 , wherein the NBIR polymer elastomeric base comprises a carboxylated acrylonitrile butadiene isoprene rubber (XNBIR) polymer elastomeric base.

3. The stator compound of claim 1 , further comprising at least one of a high reinforcing carbon black and a semi-reinforcing carbon black selected such that the stator compound has a tensile strength from about 800 to about 2000 psi 2 , an elongation from about 125 to about 300%, and a 25% modulus from about 250 to about 600 psi, when measured at 121° C.

4. The stator compound of claim 3 , wherein the high reinforcing carbon black has a surface area of about 80 to about 250 (Iodine # mg/g) and a structure of about 70 to about 178 (DBP Absorption-cc/100 g).

5. The stator compound of claim 3 , wherein the semi-reinforcing carbon black has a surface area of about 20 to about 50 (Iodine # mg/g) and a structure of about 60 to about 125 (DBP Absorption-cc/100 g).

6. The stator compound of claim 3 , wherein the stator compound comprises high reinforcing carbon black of about 5 to about 40 parts per hundred parts of the NBIR polymer elastomeric base and semi-reinforcing carbon black of about 40 to about 120 parts per hundred parts of the NBIR polymer elastomeric base.

7. The stator compound of claim 6 , wherein:

the high reinforcing carbon black has a surface area of about 80 to about 250 (Iodine # mg/g) and a structure of about 70 to about 178 (DBP Absorption-cc/100 g); and

the semi-reinforcing carbon black has a surface area of about 20 to about 50 (Iodine # mg/g) and a structure of about 60 to about 125 (DBP Absorption-cc/100 g).

8. The stator compound of claim 3 , wherein the at least one of a high reinforcing carbon black and a semi-reinforcing carbon black is further selected to provide tear characteristics at 121° C. including Die C of about 50 ppi to about 200 ppi and trouser of about 5 ppi 3 to about 100 ppi 3 .

9. The stator compound of claim 1 , wherein the NBIR polymer elastomeric base has a Mooney viscosity range of about 30 to about 85 and an acrylonitrile content range of about 28 to about 50.

10. The stator compound of claim 1 , further comprising at least one plasticizer selected from the group consisting of polymeric and ester plasticizers.

11. The stator compound of claim 1 , wherein the stator compound comprises high reinforcing carbon black of about 5 to about 40 parts per hundred parts of the NBIR polymer elastomeric base and semi-reinforcing carbon black of about 40 to about 120 parts per hundred parts of the NBIR polymer elastomeric base.

12. The stator compound of claim 11 , wherein:

the high reinforcing carbon black has a surface area of about 80 to about 250 (Iodine # mg/g) and a structure of about 70 to about 178 (DBP Absorption-cc/100 g); and

the semi-reinforcing carbon black has a surface area of about 20 to about 50 (Iodine # mg/g) and a structure of about 60 to about 125 (DBP Absorption-cc/100 g).

13. The stator compound of claim 11 , wherein the at least one of a high reinforcing carbon black and a semi-reinforcing carbon black is further selected to provide tear characteristics at 121° C. including Die C of about 50 ppi to about 200 ppi and trouser of about 5 ppi 3 to about 100 ppi 3 .

14. A stator compound comprising:

an acrylonitrile butadiene isoprene rubber (NBIR) polymer elastomeric base that has an isoprene content nominally in the range of 5-50%, wherein the acrylonitrile butadiene isoprene polymer elastomeric base is 100% non-hydrogenated; and

at least one of a high reinforcing carbon black and a semi-reinforcing carbon black selected such that the stator compound has a tensile strength from about 800 to about 2000 psi 2 , an elongation from about 125 to about 300%, and a 25% modulus from about 250 to about 600 psi, when measured at 121° C.

15. The stator compound of claim 14 , wherein the at least one of the high reinforcing carbon black and the semi-reinforcing carbon black comprises a high reinforcing carbon black of about 5 to about 40 parts per hundred parts of the NBIR polymer elastomeric base and a semi-reinforcing carbon black of about 40 to about 120 parts per hundred parts of the NBIR polymer elastomeric base.

16. The stator compound of claim 15 , wherein the high reinforcing carbon black has a surface area of about 80 to about 250 (Iodine # mg/g) and a structure of about 70 to about 178 (DBP Absorption-cc/100 g).

17. The stator compound of claim 15 , wherein the semi-reinforcing carbon black has a surface area of about 20 to about 50 (Iodine # mg/g) and a structure of about 60 to about 125 (DBP Absorption-cc/100 g).

18. The stator compound of claim 14 , wherein the at least one of a high reinforcing black and a semi-reinforcing black is further selected to provide tear characteristics at 121° C. including Die C of about 50 ppi to about 200 ppi and trouser of about 5 ppi 3 to about 100 ppi 3 .

19. A stator compound comprised of an acrylonitrile butadiene isoprene rubber (NBIR) polymer elastomeric base, wherein

the acrylonitrile butadiene isoprene polymer elastomeric base is 100% non-hydrogenated;

the NBIR polymer elastomeric base comprises a carboxylated acrylonitrile butadiene isoprene rubber (XNBIR) polymer elastomeric base; and

the stator compound further comprises at least one of a high reinforcing carbon black and a semi-reinforcing carbon black selected such that the stator compound has a tensile strength from about 800 to about 2000 psi 2 , an elongation from about 125 to about 300%, and a 25% modulus from about 250 to about 600 psi, when measured at 121° C.

20. The stator compound of claim 19 , wherein the high reinforcing carbon black has a surface area of about 80 to about 250 (Iodine # mg/g) and a structure of about 70 to about 178 (DBP Absorption-cc/100 g).

21. The stator compound of claim 19 , wherein the semi-reinforcing carbon black has a surface area of about 20 to about 50 (Iodine # mg/g) and a structure of about 60 to about 125 (DBP Absorption-cc/100 g).

22. The stator compound of claim 19 , wherein the NBIR polymer elastomeric base has a Mooney viscosity range of about 30 to about 85 and an acrylonitrile content range of about 28 to about 50.

23. The stator compound of claim 19 , further comprising at least one plasticizer selected from the group consisting of polymeric and ester plasticizers.