Dos Modified Drill Collars

Drill Collars suitable for remote controlled handling.

New regulatory requirements:
In accordance with “Facility Regulation Section § 55 and Activity Regulation Section § 80” and OLF/NR recommended guidelines nr.81: pipe- and work strings shall be suitable for remote controlled transport from storage location to rig floor.

Simultaneously “The Framework Regulations’ § 1” requires that “suitable technical, operational and organizational solutions shall be selected in order to reduce the probability for failures and accidents”.
Those solutions with the maximum reduction of risk shall be selected.

(Verbatim: In effectuating risk reduction the party responsible shall choose the technical, operational or organizational solutions which according to an individual as well as an overall evaluation of the potential harm and present and future use offer the best results.)

Present Status:
Traditional Drill Collars are designed for manual pipe handling only. Recesses for both slip and elevator are dimensioned in profile and in length for the use of manual handling equipment.

In order to avoid the use of manual elevators the standard procedure is to install lifting subs in the drill collar box end. This is done on the cat walk or in the v-door. The procedure represents manual labor exposing the workers involved to risk of injury. Use of chain tongs and mechanical lifting equipment is also required with additional failure and injury potential.

The lifting sub must be removed and lifted to storage area after drill collar has been installed in string and suspended in rotary table, exposing workers to the same risks as noted above.
Similar risk operations are required when string is retrieved.

It is estimated that a facility in drilling mode will spend an estimated 20 to 40 hours of rig time yearly on manual handling of lifting subs, installation of safety clamps, replacement of slip segments and elevator inserts due to drill collars not designed for remote controlled pipe handling.

During manual pipe handling on the rig floor it has frequently been experienced that parts of safety clamps, bolts, wrenches etc has been lost down the hole causing fishing operations and extensive down time for the facility.

The manual handling of drill collars is not in accordance with the new regulatory requirements and provides for increased safety risks for personnel involved and necessitates unwanted presence of personnel in the “red zone” on the rig floor.

Drill collars adapted for remote controlled handling:
Drill collars are presently available designed for safe remote controlled handling and use.
The upper section (suspension area) of the drill collar is designed and manufactured in accordance with the required drill pipe configuration in order to utilize the same remote controlled elevators and slips as used for the drill pipe. The elevator shoulder is 18°.

The slip recess is designed for use with remote controlled slips.(type PS-21/-30 etc)
Use of remote controlled slip eliminates the need for installation of safety clamps.

The drill collars may now be handled by remote control like the normal drill pipe and in full accordance with the regulatory requirements.

Additional advantages for drill collars with drill pipe configuration are improved flexibility for high deviation operations, milling operations, whipstock installations, running liners and screens.
Drill collars with drill pipe configuration and adapted for drill pipe elevators and slips are inherently less exposed to high stress concentrations.

More (pdf):
1.1. 8 1/4" DC with drill pipe configuration
1.2. 6 3/4" DC with drill pipe configuration
1.3. 4 3/4" DC with drill pipe configuration
1.4. Tool joint with 18 degree taper 
1.5. Standard & alternative zip configuration
1.6. Options
1.7. Mill cert example

Product sheets:
SDC 4,75 Summary Data Sheet FP Rev 3 11 b
SDC 6,50 Summary Data Sheet FP Rev 3 11 b
SDC 6,75 Summary Data Sheet FP Rev 3 11 b
SDC 8,00 Summary Data Sheet FP Rev 3 11 b
SDC 8,25 Summary Data Sheet FP Rev 3 11 b



Dahl Oilfield Services AS / Hammaren 9A, 4056 Tananger / tlf:+4751419000 / post@dahl-os.no