The scramble to secure rigs for deepwater development in the wake of $100 oil prices and rapidly tightening, global, spare-production capacity is now impacting day rates for down-market units.

A recent increase in fixtures for midwater equipment -- in two cases involving rigs that are old enough in human terms to be approaching a midlife crisis -- echo the rapidly rising rates that hitherto were confined to the ultra- deepwater sector (UDW).

In March, Noble’s Max Smith was awarded a three-year contract with Shell offshore Brazil that will generate $407,000 per day (including a 15% performance bonus). The 7,000-foot rated, fourth-generation, semisubmersible will commence work in December 2012.

Elsewhere, Transocean’s 36-year old Discoverer Seven Seas , a 7,000-ft drillship, signed on with ENI for a three-well contract in Indonesia at $445,000/d beginning in May 2012. Analysts had modeled rates for the Transocean unit in the $385,000 range. The floater had a storied history following its commissioning in 1976 as the most advanced drillship of its time. The unit set a number of depth records , including several for Shell in the Gulf of Mexico (GOM) before being surpassed by newer higher-spec units.

A driver behind the recent inflection point for midwater or lower-spec deepwater rig rates is the rapidly diminishing visibility for UDW unit availability. That intensifying dynamic prompted Morgan Stanley ’s Ole Slorer to project a super spike in rig rates to greater than $700,000/d for UDWs.

“Over the next 12 months, true UDW availability is down to three units while third-generation/fourth-generation availability stands at 25 units. With requirements for 30 floaters over the same period from current firm tenders alone, we see a ‘short squeeze’ playing out over coming quarters,” Slorer wrote in an early March research report.

Separately, Barclays Capital has identified 12-marketed deepwater units rated from 5,000 to 7,499 ft with some availability in 2012, including four that belong to Transocean.

“Recent fleet status reports, tender announcements and exploration successes indicate favorable trends are set to continue for the offshore drillers,” noted James West , Barclays Capital oil services analyst. “Activity in West Africa , the North Sea, and the Middle East is improving while the recovery in the GOM is set to reach another inflection point, in our opinion.”

West expects rates for UDW units will top $600,000 by midyear. UDW rates breached the $500,000 threshold less than six months ago.

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