Page 70: of Offshore Engineer Magazine (May/Jun 2013)

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Coiled tubing use extends offshore productivity

Production

New uses for present technology with new equipment to further effectiveness

By Victor Schmidt a new tool, the Well Cutter, and was

The Coiled Tubing and Well Interven- presented with the winner’s trophy, tion Conference, sponsored by ICoTA, the Quaich cup, which it later dis- the Intervention and Coiled Tubing played in its booth. The electric-line

Association, was held in late March conveyed tool is a mechanical cutter in The Woodlands Conference Center that uses grit-embedded pads to cut north of Houston. Speakers presented tubulars. The pads are expanded a range of operational experience, outward at the bottom of the tool to practices, and well intervention im- contact the inner pipe wall, and then

Figure 1. ICoTA awarded its annual provements using coiled tubing and are rotated to sever the pipe, Fig. 1.

Intervention Technology Award to other techniques. Sessions included The tool’s operation was explained

Welltec for its Well Cutter tool. electric line, slickline, and wireline in technical paper SPE 163890, operations, fracturing and stimulation “Electric-line pipe-cutting operation using coiled tubing (CT), as well as optimizes completion removal, off- hammer for extended-reach applica- offshore and subsea well interven- shore Russia.” During the operation, tions.” The CT-MWD (coiled tubing- tion. Among the highlights: the tool successfully cut a 4½-in., measurement while drilling) tool sits 12.6lb/ft tubing below 2,133m, in a behind the bit and uses an actuator

Velocity strings 57° deviated well off the east coast system to create low-frequency vibra-

In the North Sea, older felds are of Russia. Cutting time was about 80 tions in the drilling mud stream that being brought back into production minutes. serve two purposes. First, the vibra- by installing coiled tubing as veloc- Metal flings produced by the tion excites the coiled tubing (CT) to ity strings to unload excessive fuid pads were easily fushed out of the keep it moving through tight sections from gas wells. Speakers from Neth- wellbore, unlike shards from ex- or when lying against the bottom erlands-operator NAM (Nederlandse plosive cutting, or metal chips and of the hole while drilling lateral

Aardolie Maatschappij) presented curls from a milling tool. Because sections. Second, the induced fuid

SPE 163905, “Extending the opera- the cut was clean, no additional trip vibrations can be used to transmit tion life of mature North Sea assets to collect junk or dress the top of the data uphole from other sensors in the by big-scale offshore installation of remaining pipe was required. The bottom hole assembly. large-diameter chrome coiled-tubing cut left a smooth, beveled interior Traditional mechanical water ham- velocity strings.” surface to the pipe, which was eas- mer systems operate at frequencies

NAM installed 2 3/8in. and 2 ily fshed, and the remaining pipe of 12-40 Hz, are generally preset for 7/8in. 16-Chrome coiled tubing in pulled. a given drilling mud circulation rate, 20 wells, using a dedicated, self- The operator Sakhalin Energy, real- and are not adjustable. The program- propelled jackup during a two-year, ized signifcant cost savings because mable pulse technology in the new feld-life extension project. The crew no explosives were used to cut the tool allows the pulse amplitude to installed the pipe in wells on small pipe. They did not have to pay for be varied without tripping out of the production platforms and unmanned explosives permits, follow special hole. installations after a careful evalua- procedures, provide additional se- The tool modulates circulation tion process to identify wells that curity or special storage, limit radio pressure in the 1.5-2Hz frequency would best beneft from deliquifca- or vessel traffc, or spend extra rig range to vary load on the bit, creating tion. Gas production after the work- time on secondary runs to dress a axial oscillation in the tubing. This overs increased by 1.7–5.3MMcf/d fared, ragged pipe end. The tool can “ballooning effect” reduces fric- per well, returning the wells to be used on drill pipe, liner, tubing, tion along the pipe, prevents helical proftable operation and extending packers, or casing. buckling, improves weight transfer their economic life. for milling and drilling operations,

Vibration-enhanced drilling and increases CT reach. TeleDrill

Another new tool at the event was continues to develop the tool and

Clean cutting

Welltec won ICoTA’s seventh annual presented by TeleDrill Inc. in SPE has schedule additional feld tests for

Intervention Technology Award for 163883, “Low frequency water later this year.

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