Open hole non-rotating sleeve and assembly
A non-rotating downhole sleeve adapted for open hole drilling and/or casing centralization. The sleeve includes a tubular body made of hard plastic with integrally formed helical blades positioned around its outer surface and an inner surface configuration which allows drilling fluid circulation to form a non-rotating fluid bearing between the sleeve and the drill pipe or casing. The helical blades reduce sliding and rotating torque while drilling, with minimal obstruction to drilling fluid passing through the borehole between the blades.
1. A non-rotating downhole sleeve adapted for open hole drilling and/or centralization in a casing or on a casing in a wellbore, the downhole sleeve comprising:
a tubular body made from a molded polymeric material and having an inside surface adapted to surround a drill pipe or casing, the inside surface of the tubular body having circumferentially spaced apart axially extending grooves positioned between substantially flat bearing surface regions for contacting the outer surface of the drill pipe or casing, the axial grooves allowing drilling fluid to circulate therethrough to form a non-rotating fluid bearing upon circulation of fluid between the tubular body and the drill pipe or casing, characterized in that:
the tubular body has a plurality of helical blades integrally formed with the polymeric tubular body and projecting from an outer surface of the tubular body, the helical blades having outer surfaces adapted for contact with the casing or an open hole drilled in formation below a casing exit, the blades providing a flow path for fluid passing between the blades, the flow path passing through the wellbore between upper and lower ends of the tubular body, in which the helical blades have a blade height (h) and an average blade width (w) such that during rotation of the sleeve a minimum of two blades are positioned to contact the casing exit,
the blades have a generally parallel and helical spacing having an average distance between blades which is substantially equal to the average width (w) of the helical blades.
2. Apparatus according to claim 1 in which the tubular body comprises an interior liner forming the flat surface regions and axial grooves of said fluid bearing and a tubular outer section made of said molded polymeric material integrally formed with said helical blades, the inner liner bonded to the tubular outer section, the inner liner having a hardness less than the hardness of the tubular outer section, in which the inner liner is made from a thermoplastic elastomer, soft plastic, or rubber-containing material having a Shore A hardness from about 55 to about 75, and in which the tubular outer section is made of ultra high molecular weight polyethylene.
3. Apparatus according to claim 1 in which the tubular body further includes a reinforcing cage structure of heat treatable steel having a thickness of at least about 0.065 inch embedded in and circumferentially encircling the tubular body of the sleeve.
4. Apparatus according to claim 3 in which the molded tubular body comprises ultra high molecular weight polyethylene, and the tubular body has an average compression loading resistance of at least about 40,000 pounds.
5. Apparatus according to claim 3 in which the tubular body contains at least one hinged structure affixed to the reinforcing cage and made of heat treatable steel of the same minimum thickness as the cage.
6. Apparatus according to claim 1 in which the sleeve has a sliding coefficient of friction (when sliding and rotating in a drilling fluid) and a rotating coefficient of friction (when sliding and rotating in drilling fluid) of 0.10 or less.
7. Apparatus according to claim 1 in which the helical blades extend generally parallel to one another with intervening parallel and helical spacing having an average width substantially equal to no more than the average blade width (w).
8. Apparatus according to claim 1 in which the tubular body of the sleeve contains anti-spin grooves in its outer surface.
9. Apparatus according to claim 1 in which the number (N) of blades on the tubular body is equal to:
N =π( R c +t+h )/ w
wherein:
R c =sleeve radius
t=sleeve thickness
h=blade height
w=average blade width.
10. Apparatus according to claim 9 in which the helical blades have an arc angle equal to:
(
360
w
)
π
(
R
c
+
t
+
h
)
.
11. A method of reducing torque when drilling in an open hole environment, the method including drilling a borehole with a rotary drill pipe, the drill pipe having installed thereon at least one non-rotating downhole sleeve having a tubular body disposed around the drill pipe, the tubular body made from a molded polymeric material, the inside surface of the tubular body having a combination of axial grooves and substantially flat intervening axial regions forming a non-rotating fluid bearing around the drill pipe, characterized in that the tubular body has a plurality of helical blades integrally formed with the polymeric tubular body and projecting from the outer surface of the tubular body, the method including drilling an open hole with the drill pipe while circulating fluid through the borehole, the axial grooves of the sleeve allowing drilling fluid to circulate therethrough to provide a non-rotating fluid bearing between the sleeve and the drill pipe, the helical blades having outer surfaces adapted to contact the open hole while providing a flow path through the open hole past the helical blades, in which the borehole includes a casing and the open hole is drilled in formation below a casing exit, and in which the helical blades have a blade height (h) and an average blade width (w) such that during rotation of the sleeve a minimum of two blades are positioned to contact the casing exit, the blades have a generally parallel and helical spacing having an average distance between blades which is substantially equal to the average width (w) of the helical blades.
12. The method according to claim 11 in which the tubular body comprises an interior liner forming the flat surface regions and axial grooves of said fluid bearing and a tubular outer section made of said molded polymeric material integrally formed with said helical blades, the inner liner bonded to the tubular outer section, the inner liner having a hardness less than the hardness of the tubular outer section.
13. The method according to claim 12 in which the inner liner is made from a thermoplastic elastomer, soft plastic or rubber-containing material having a Shore A hardness from about 55 to about 75, and in which the tubular outer section is made of ultra high molecular weight polyethylene.
14. The method according to claim 11 in which the tubular body includes an embedded reinforcing cage structure of heat treatable steel having a thickness of at least about 0.065 inch.
15. The method according to claim 11 in which the number (N) of blades on the tubular body is equal to:
N =π( R c +t+h )/ w
wherein:
R c =sleeve radius
t=sleeve thickness
h=blade height
w=average blade width.
16. The method according to claim 15 in which the helical blades have an arc angle equal to:
(
360
w
)
π
(
R
c
+
t
+
h
)
.
17. A non-rotating downhole sleeve adapted for open hole drilling and/or centralization in a casing or on a casing in a wellbore, the downhole sleeve comprising:
a tubular body made from a molded polymeric material and having an inside surface adapted to surround a drill pipe or casing, the inside surface of the tubular body having circumferentially spaced apart axially extending grooves positioned between substantially flat bearing surface regions for contacting the outer surface of the drill pipe or casing, the axial grooves allowing drilling fluid to circulate therethrough to form a non-rotating fluid bearing upon circulation of fluid between the tubular body and the drill pipe or casing,
the tubular body has a plurality of helical blades integrally formed with the polymeric tubular body and projecting from an outer surface of the tubular body, the helical blades having outer surfaces adapted for contact with the casing or an open hole drilled in formation below a casing exit, the blades providing a flow path for fluid passing between the blades, the flow path passing through the wellbore between upper and lower ends of the tubular body, in which the helical blades have a blade height (h) an average blade width (w) that during rotation of the sleeve a minimum of two blades are positioned to contact the casing exit wherein:
(a) the sleeve is made from ultra high molecular weight polyethylene,
(b) the sleeve includes a heat treatable steel cage having a thickness of at least about 0.065 inch,
(c) the blades extend generally parallel to one another with a generally uniform spacing between them, and
(d) the number (N) of helical blades in the sleeve is equal to:
N =π( R c +t+h )/ w
wherein:
R c =sleeve radius
t=sleeve thickness
h=blade height
w=average blade width.
18. A method of reducing torque when drilling in an open hole environment, the method including drilling a borehole with a rotary drill pipe, the drill pipe having installed thereon at least one non-rotating downhole sleeve having a tubular body disposed around the drill pipe, the tubular body made from a molded polymeric material, the inside surface of the tubular body haying a combination of axial grooves and substantially flat intervening axial regions forming a non-rotating fluid bearing around the drill pipe, characterized in that the tubular body has a plurality of helical blades integrally formed with the polymeric tubular body and projecting from the outer surface of the tubular body, the method including drilling an open hole with the drill pipe while circulating fluid through the borehole, the axial grooves of the sleeve allowing drilling fluid to circulate therethrough to provide a non-rotating fluid bearing between the sleeve and the drill pipe, the helical blades having outer surfaces adapted to contact the open hole while providing a flow path through the open hole past the helical blades in which the borehole includes a casing and the open hole is drilled in formation below a casing exit, and in which the helical blades have a blade height (h) and an average blade width (w) such that during rotation of the sleeve a minimum of two blades are positioned to contact the casing exit wherein:
(a) the sleeve is made from ultra high molecular weight polyethylene,
(b) the sleeve includes a heat treatable steel cage having a thickness of at least about 0.065 inch,
(c) the blades extend generally parallel to one another with a generally uniform spacing between them, and
(d) the number (N) of helical blades in the sleeve is equal to:
N =π( R c +t+h )/ w
wherein:
R c =sleeve radius
t=sleeve thickness
h=blade height
w=average blade width.