Hydra Rig, a division of Tuboscope's coiled tubing (CT) and wireline group, has developed a drop-in drum (DID) and mounting system for steel CT that eliminates respooling from a shipping drum onto a work drum.

Soon CT will be wrapped on a DID at the factory and shipped. The drum will slide into mounting slots on the CT reel stand and lock itself in so the tubing can go directly to work. Accompanying this development are a new 60,000lb pull injector and a new, lightweight, 15,000-psi blowout preventer (see related sidebar).
The DID is a development the CT industry has been looking forward to almost since the CT business began to ramp up in the mid-1980s.
As applications intensified in the 1990s, improvements began to be made in the tubing technology to include longer, stronger and thicker-walled tubing of greater diameters. Associated tools and running equipment have been developed to handle the stronger pipe. Increasingly, jobs previously done by workover and snubbing units have been taken over. Applications demanding high load capacity with fine control, such as CT drilling and CT logging, commonly are done by CT units.
Advantages
But of the many improvements, the one asked for most often in the industry has been elusive: the DID. Essentially, this design would create a purpose-built shipping and storage drum that also is the work drum in the reel. Potential gains are huge, amounting to a paradigm change. The drum will:
• Increase life of the CT coil. With coils averaging 20 respoolings before retirement, elimination of the first one from shipping reel to work drum represents a 5% increase in useful life;
• Eliminate or minimize yard spooling, thus eliminating the associated labor, safety hazards and pipe-fatigue cycles. Yard spoolers would not become obsolete, but the need for them would be minimized;
• Allow quick pipe change, either in the yard or on location, to rapidly respond to changing job needs;
• Reduce total pipe inventory. Since the drums would become an industry standard, special pipe or pipe configurations could be inventoried for multiple users; and
• Allow more offshore lift flexibility. The drum and reel stand could be lifted separately, increasing pipe length for a given crane capacity.
Hydra Rig focused on the design parameters for the DID in 1999 during the industry downturn. Existing designs were evaluated, but none hit the mark. The company decided to start with a blank sheet of paper and these design objectives:
• Keep it simple. Make the drum as simple and economical to build as possible. Any complexity should be in the reel stand;
• Focus on the drum/reel interface. Aspects such as drive system, lifting method, fluid passage or e-line capability then can be dependent on and evolve from the drum/reel interface;
• Build the drum to drop in and lock to the reel stand with as simple a mechanism as possible. Avoid pivoting reel stand pedestals and translating shafts. Assume a crane would be available for drop-in and removal;
• Cover a broad size range. Bearings, drum/reel interface components, gearboxes and motors should be common over a range of sizes for parts commonality; and
• Make the drum adaptable. It should accommodate or be easily adaptable to mill pipe spoolers.
The project began in mid-1999, and the decision to prototype was made in the fall of 1999 with the goal of a working model at the 2000 Offshore Technology Conference (OTC) in Houston.
During the first quarter of 2000, Hydra Rig visited major service companies to present the DID and get feedback and validation that the design and concept were fit-for-purpose. Feedback from service company customers was enthusiastic.
Additionally, Hydra Rig visited the major CT pipe suppliers for the same purpose. Several minor changes were suggested to facilitate mill pipe spooling; these changes will be incorporated in production models.
The prototype will undergo extensive testing and a field application prior to release. Several customers have committed to assist with beta testing. The DID should be ready to commercialize by the fourth quarter of 2000.
Product features
The DID system is designed so that the drum is as simple and economical to build as possible, but has the strength and design tolerances to function as the work reel.
The drum drops in and mechanically locks to the reel stand. No pivoting pedestals, translating arms, shafts or hydraulic lifts are necessary. The drum adapts to mill pipe spoolers.
The 2000 series DID is road-legal width and can be transported on a single-drop float. The intermediate 3000 series is road-legal and can be transported on a double-drop float. With frames removed, these reels can be mounted on a purpose-built trailer with the drum extending through the trailer rails.
A larger, 4000 series DID is under development. The full line will handle a range of CT from 30,000ft of 1in. tubing to 7,200ft of 3½in. tubing.
The reel and drum designs (patents pending) accommodate a swivel for the fluid path, a means to exit e-line and a quick, simple way to adjust the level-wind and counter to accommodate different
pipe sizes.
The key to the system is the latch connection between drum and reel. It is similar to a fifth wheel on a tractor, except once latched, rotation is locked between the drum and reel-drive mechanism.