Changes

|+ {{table number|1}}Conventional coring systems

|+ {{table number|1}}Conventional coring systems

|-

|-

! Inner Barrel

! Inner Barrel || Core Length (ft) || Special Features

! Core Length (ft)

! Special Features

|-

|-

| Mild steel

| Mild steel || 30–120 || Ready-made core preservation system; high temperature applications

| 30–120

| Ready-made core preservation system; high temperature applications

|-

|-

| Mild steel

| Mild steel || 1.5 || Designed for short radius coring

| 1.5

| Designed for short radius coring

|-

|-

| High strength steel

| High strength steel || 120–>400 || Stronger barrel, includes additional inner and outer core barrel stabilization

| 120–>400

| Stronger barrel, includes additional inner and outer core barrel stabilization

|-

|-

| Fiberglass

| Fiberglass || 30–90 || Ready-made core preservation system; used for consolidated and unconsolidated formations

| 30–90

| Ready-made core preservation system; used for consolidated and unconsolidated formations

|-

|-

| Aluminum

| Aluminum || 30–90 || Ready-made core preservation system; high temperature applications

| 30–90

| Ready-made core preservation system; high temperature applications

|-

|-

| Steel with a plastic liner

| Steel with a plastic liner || 30 || Ready-made core preservation system; maximum temperature [[temperature::180°F]]; reduces core diameter by 0.5 in.

| 30

| Ready-made core preservation system; maximum temperature [[temperature::180°F]]; reduces core diameter by 0.5 in.

|-

|-

| Steel with a fiberglass liner

| Steel with a fiberglass liner || 30 || Ready-made core preservation system; maximum temperature [[temperature::250°F]]; reduces core diameter by 0.5 in.

| 30

| Ready-made core preservation system; maximum temperature [[temperature::250°F]]; reduces core diameter by 0.5 in.

|-

|-

| Steel with a steel liner

| Steel with a steel liner || 30 || Ready-made core preservation system; maximum temperature [[temperature::350°F]]; reduces core diameter by 0.5 in.

| 30

| Ready-made core preservation system; maximum temperature [[temperature::350°F]]; reduces core diameter by 0.5 in.

|}

|}

The ''core catcher'', the device that holds the core in the barrel, is tailored to the type of inner barrel and lithology expected. Table 2 lists core catchers by their common names and usages. In some cases, multiple catchers are used. Friable sandstone interbeddded with shale might require both slip and flapper type catchers. Full-closure catchers, run primarily to ensure success when coring unconsolidated sand, also incorporate split ring or slip type catchers to improve core recovery in the event that coring ends in hard rock.

The ''core catcher'', the device that holds the core in the barrel, is tailored to the type of inner barrel and lithology expected. Table 2 lists core catchers by their common names and usages. In some cases, multiple catchers are used. Friable [[sandstone]] interbeddded with shale might require both slip and flapper type catchers. Full-closure catchers, run primarily to ensure success when coring unconsolidated sand, also incorporate split ring or slip type catchers to improve core recovery in the event that coring ends in hard rock.

{| class = "wikitable"

{| class = "wikitable"

|+ {{table number|2}}Core catchers

|+ {{table number|2}}Core catchers

|-

|-

! Type

! Type || Recommended Usage

! Recommended Usage

|-

|-

| Split ring or spring

| Split ring or spring || Consolidated formations

| Consolidated formations

|-

|-

| Collet

| Collet || Where formation characteristics are unknown

| Where formation characteristics are unknown

|-

|-

| Slip

| Slip || Consolidated formations, normally run with flapper catcher or with orientation knives

| Consolidated formations, normally run with flapper catcher or with orientation knives

|-

|-

| Dog or flapper

| Dog or flapper || Consolidated, fractured, and unconsolidated formations where geology is unknown

| Consolidated, fractured, and unconsolidated formations where geology is unknown

|-

|-

| Basket

| Basket || Unconsolidated formations, normally run with another core catcher type

| Unconsolidated formations, normally run with another core catcher type

|-

|-

| Full closure

| Full closure || Friable to unconsolidated formations to provide full closure

| Friable to unconsolidated formations to provide full closure

|}

|}

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 rig|offshore]] settings. The marine barrel increases the margin of safety against tool failure, but is restricted to cutting a 3-in.-diameter core.

Today's special heavy duty core barrels have been developed to core harder than normal formations and to cut extended length cores. These tools are designed to cut cores up to 5.25 in. in diameter. Heavy duty threads allow more torque to be applied to the bit and improve the margin of safety against tool failure.

Today's special heavy duty core barrels have been developed to core harder than normal formations and to cut extended length cores. These tools are designed to cut cores up to 5.25 in. in diameter. Heavy duty threads allow more torque to be applied to the bit and improve the margin of safety against tool failure.

[[Category:Wellsite methods]]

[[Category:Wellsite methods]]