10,323
edits
Changes
Jump to navigation
Jump to search
Line 99:
Line 99: − − [[file:conventional-coring_fig2.png|thumb|{{figure number|2}}Sponge-lined coring system. © DBS, a Baroid Company.]] Line 111:
Line 109: + +
→Special coring
A heavy duty core barrel should be considered when cutting long lengths of relatively homogeneous formations or when anticipating higher than normal torque loads. This system can also be especially attractive when rig time is the largest component of the coring expense.
A heavy duty core barrel should be considered when cutting long lengths of relatively homogeneous formations or when anticipating higher than normal torque loads. This system can also be especially attractive when rig time is the largest component of the coring expense.
The precursor of today's heavy duty core barrels is the marine core barrel. This tool was developed to be stronger than conventional systems for use in offshore settings. The marine barrel increases the margin of safety against tool failure, but is restricted to cutting a 3-in.-diameter core.
The precursor of today's heavy duty core barrels is the marine core barrel. This tool was developed to be stronger than conventional systems for use in offshore settings. The marine barrel increases the margin of safety against tool failure, but is restricted to cutting a 3-in.-diameter core.
===Core barrel liners===
===Core barrel liners===
[[file:conventional-coring_fig2.png|thumb|{{figure number|2}}Sponge-lined coring system. © DBS, a Baroid Company.]]
PVC plastic, ABS plastic, and aluminum have all been used as inner core barrel liners. The liner slips inside a steel inner core barrel, reducing the effective inner diameter of the core barrel by approximately 0.5 in. The liner simplifies [[core handling]], especially for friable or unconsolidated core, and serves as a core preservation system. Liners are less expensive than disposable inner core barrels. However, besides reducing the diameter of the core, they restrict the length of the core to [[length::30 ft]].
PVC plastic, ABS plastic, and aluminum have all been used as inner core barrel liners. The liner slips inside a steel inner core barrel, reducing the effective inner diameter of the core barrel by approximately 0.5 in. The liner simplifies [[core handling]], especially for friable or unconsolidated core, and serves as a core preservation system. Liners are less expensive than disposable inner core barrels. However, besides reducing the diameter of the core, they restrict the length of the core to [[length::30 ft]].