Page 64: of Offshore Engineer Magazine (Sep/Oct 2013)

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Drilling

Achieving total isolation to optimize wellbore cleaning rilling mud displacement psi; thus, any pressure loss in the annu-

The combined application of the is a critical step in the well lus up to this pressure will have no

ISO-MAX security packer and construction process to ensure effect on the formation. Bypass valves

D selective rotation and circulation completions operations are conducted incorporated into the packer body tool (SRCT) helped a North Sea in a clean, solids-free wellbore envi- enable test fuid to be pumped with the ronment. However, displacement annulus sealed, and allow the packer operator prevent losses during operations also introduce the risk of to be set only once. The unique setting well displacement, thus ensuring fuid losses that, if left unchecked, can and unsetting features of the ISO-MAX well integrity and improving lead to a poor completion and subse- security packer, also allows for drilling the chances of a successful quent well control problems. While of shoetrack to be performed after the even minor losses have the potential to infow test.

completion. damage the formation and reduce pro- The packer can be run with several duction rates, more serious losses may wellbore cleaning tools, such as the

By Michael Ronson, lead to runaway well control problems selective rotation and circulation tool

Weatherford in the form of a blowout. (SRCT), a repeat-cycle, shear-activated

Weatherford has worked closely with fow tool primarily designed for several operators to advance packers wellbore cleaning in deviated wells and wellbore cleaning tools that limit with liners. The tool has a disengaging losses and validate well integrity during spline drive, which allows the operator displacement operations, thus ensur- to rotate the upper part of the drill- ing a successful completion operation. string while the lower part remains

One such advancement, the ISO-MAX stationary, avoiding the risk of twisting security packer, is a drillpipe-conveyed off the lower (weaker) string while dis- downhole liner-top test packer that placing to completion fuid and losing enables the negative testing of a liner lubricity from the drilling fuid. overlap and shoe track while used Rotation of drillstrings in wellbores in conjunction with other wellbore containing small-diameter liners has cleanup activities such as mechani- historically proven diffcult due to cal scraping, debris removal and mud excessive torque, which hinders well- displacement to a completion fuid. bore cleaning by preventing effective

Combining pressure testing and well- agitation of cutting beds and other bore cleaning operations in a single trip debris. The SRCT contains fow ports avoids the need for a separate retriev- that are closed during normal opera- able-packer run or wellbore displace- tions, which allows fow to be directed ment to a lower-density fuid through to the lower part of the string. Once the choke, thus saving cost and risk. the tool reaches a predetermined point

The packer can be run in hole (RIH) such as a liner top, weight is set down or pulled out of hole (POOH) without on the string to activate / shear a shear speed restrictions, and is set hydrauli- ring that allows the disengaging of the cally, which avoids the need to apply spline from the lower portion of the excessive weight to the liner top to set string. The upper part of the string is the tool after drilling cement and before then free to rotate, while the lower infow testing. This setting feature also portion sees no torque and remains allows multiple sizes to be run simul- stationary. With the spline disengaged taneously to test more than one liner the fow ports are open, which divert on the same run—another cost-saving fow to the annulus to increase fuid beneft over conventional systems. Once velocity. It should be noted that the set, the packer seals the well below it SRCT can be opened or closed at any

The ISO-MAX up to a differential pressure of 5,000 point in the displacement operation. security packer

OE | September 2013 oedigital.com 66 000_OE0913_D&C3-Weatherford_Interv.indd 66 8/18/13 8:32 PM