Inhibiting wellbore deformation during in situ thermal processing of a hydrocarbon containing formation

A method for treating an oil shale formation comprising:

• providing heat from one or more heaters to at least a portion of the oil shale formation, wherein at least one of the heaters is in an uncased portion of a wellbore in the oil shale formation, wherein the uncased portion of the wellbore has been sized, at least in part, so that a minimum space between the heater and the oil shale formation is maintained after expansion of the oil shale formation in the wellbore caused by heating of the oil shale formation, and wherein the expansion of the oil shale formation in the wellbore is estimated based on the richness of one or more zones in the oil shale formation;
• and
• allowing the heat to transfer from the one or more heaters to a part of the oil shale formation;
• and
• producing a mixture from the oil shale formation.

A method for treating a coal formation, comprising:

• providing heat from one or more heaters to at least a portion of the coal formation, wherein at least one of the heaters is in an uncased portion of a wellbore in the coal formation, wherein the uncased portion of the wellbore has been sized, at least in part, so that a minimum space between the heater and the coal formation is maintained after expansion of the formation in the wellbore caused by heating of the coal formation, and wherein the expansion of the coal formation in the wellbore is estimated based on the richness of one or more zones in the coal formation;
• and
• allowing the heat to transfer from the one or more heaters to a part of the coal formation;
• and
• producing a mixture from the coal formation.