摘要：
Solid polymer objects have size at least 0.5 mm in each of three orthogonal dimensions and shape such that each object has one or more edges, points or corners and/or has a plurality of projections which extend out from a core portion. Such objects may be included in a drilling fluid as a lost circulation additive intended to bridge fractures and mitigate fluid loss. Their angular shape features make it harder for them to slide over fracture faces or each other and helps them to bridge a fracture. A method of making these objects provides a travelling endless belt made of elastomer and defining mould cavities. The mould cavities are filled with a polyerisable liquid composition, which is cured in the mould as the belt advances, and the cured objects are ejected from a mould as the belt bends around a roller.
权利要求：
CLAIMS
1. A method of making solid objects formed of polymeric material, having
sufficient rigidity to sustain their own shape, wherein the objects have an
overall size extending at least 0.5mm in each of three orthogonal dimensions
and wherein the objects have a shape such that each object has one or more
edges, points or corners and/or comprises a core portion with a plurality of
projections which extend out from the core portion,
the method comprising providing at least one mould for the objects,
introducing a curable liquid composition into the mould, curing the
composition to a solid state in the mould and then releasing the cured
objects from the mould.
2. A method according to claim 1 wherein the mould is flexible and the method
comprises bending the at least one mould to eject the cured objects. 3. A method according to claim 2 wherein a plurality of moulds are formed in
an endless belt, the method comprising moving the belt through a mould-
filling station at which the liquid composition is introduced into the mould,
through a curing zone and then around a bend at which the cured objects are
ejected from the moulds in the belt.
4. A method according to claim 3 wherein moving the belt around a bend is
running the belt around a roller to change its direction of motion. 3 A method according to claim 1 wherein releasing the objects from the mould
comprises melting or dissolving the mould.
6. A method according to claim 1 or any one of claims 2 to 5 wherein curing the
liquid composition is a photocuring process in which the composition is
irradiated with visible or ultraviolet light to initiate polymerisation.
7. A method according to claim 1 or any other of comprising making the at least
one mould by an additive manufacturing process.
8. A method according to claim 7 comprising making a part of the belt with
moulds therein by inkjet printing of a flexible polymer.
9. A method according to claim 1 or any other of the preceding claims wherein
at least some of the objects have a shape which is at least partially bounded by
surfaces which intersect at an edge.
10. A method according to claim 9 wherein at least some of the objects have
shapes where the angle included between surfaces intersecting at an edge is
not more than 150°.
11. A method according to claim 1 or any other of the preceding claims wherein
at least some of the objects have a shape such that the object has one or more
points or corners which include angles which are less than 90° when viewed
in two orthogonal directions or which include a solid angle of less than 0.57
steradians.
12. A method according to claim 1 or any other of the preceding claims wherein
at least some of the objects comprise a core with a plurality of projections
which extend out from the core.
13. A method according to claim 12 wherein the projections extend out from the
core for a distance greater than a distance across the core.
14. A method according to claim 1 or any other of the preceding claims wherein
the cured composition is an organic polymer with a specific gravity in a range
from08to 1.2.
15. A method according to claim 1 or any other of the preceding claims wherein
at least some of the objects are too large to fit within a sphere of Imm
diameter, but are able to fit within a sphere of 8mm diameter.
16. A method according to claim 1 or any other of the preceding claims wherein
the objects are dimensioned such as to be too large to fit inside a sphere of
1.5mm diameter but small enough to fit inside a sphere with a diameter of
6mm.
17. A method according to claim 1 or any other of the preceding claims , further
comprising incorporating the objects into a drilling fluid and circulating the
drilling fluid down and back up a borehole.