Highly crosslinked polymer particulate

A crosslinked polymer particulate, comprising:

• a plurality of crosslinked polymer granules, each containing a crosslinked polymeric material that includes:
• (i) a plurality of polyethylene polymer chains;
• and
• (ii) a plurality of chemical crosslinks, wherein the plurality of chemical crosslinks includes chemical crosslinks that covalently bond a given polyethylene polymer chain of the plurality of polyethylene polymer chains to another polyethylene polymer chain of the plurality of polyethylene polymer chains, wherein the plurality of crosslinked polymer chains has an average degree of crosslinking of at least 0.1%;
• and wherein a characteristic dimension of each crosslinked polymer granule of the plurality of crosslinked polymer granules is at least 10 micrometers and at most 5 millimeters, wherein, when subjected to a confining stress of 42 Megapascals at a temperature of 85 degrees Celsius, a monolayer of the crosslinked polymer particulate defines a fluid conductivity of at least 1×104 micrometers3.