Abstract: An improved particulate material is disclosed for use in a method for altering the permeability of a gravity override or relatively high permeability path through a subsurface earth formation resulting from fluid injection into the subsurface formation. The method includes adding selectively sized, finely divided, amorphous non-abrasive particulate material to a fluid and injecting the fluid into the gravity override or relatively high permeability path to deposit the particulate material thus altering the permeability in the override, or relatively high permeability path. The particulate material may include graphite, carbon black, clay suspensions, quartz, or other minerals reduced in size range to behave as non-abrasive amorphous material which will present a non-abrasive characteristic in injection wells and if the particulate material is produced with formation fluids from the treated formation.

Abstract: A hull heating system for an offshore production structure for use in arctic waters wherein the heat from the produced fluids is used to maintain the temperature of the outer surface of the structure above the melting temperature of the ice adjacent the structure.