In a remarkable run of luck, a clutch of petroleum companies prospecting for oil and gas in the deepwater portion of the US Gulf of Mexico have collectively struck big-time paydirt, with one discovery quite possibly holding up to 1billion barrels oil equivalent.
US independent Cobalt International Energy has revealed what it described as “extraordinary results” from the Shenandoah-2R appraisal well drilled by operator Anadarko on Walker Ridge block 51 in the US Gulf of Mexico. Speculation is that an elephant class field may have been found.
The Shenandoah-2R appraisal encountered more than 305 net metres (1,000 net feet) of oil pay in multiple high-quality Lower Tertiary-aged reservoirs. Log and pressure data from both the latest well and the 2009 Shenandoah discovery well indicate the presence of exceptionally high-quality reservoirs and hydrocarbons.
According to US Citi analyst Robert Morris, Shenandoah could potentially contain between 500million and 1billion barrels oil equivalent with first commercial oil expected in 2017.
The appraisal was drilled as a straight hole to a total depth of 9,572m (31,405ft) in approximately 1,767m (5,800ft) of water, about 2km (1.3 miles) south-west and some 518m (1,700ft) structurally down-dip from the Shenandoah-1 discovery well, in order to test the down-dip extent of the field.
Well results indicate that the targeted sands were full to base with no evidence of oil-water contacts.
The original Shenandoah-1 discovery well encountered more than 300 net feet of Inboard Lower Tertiary oil pay.
This wasn’t the only big success for Cobalt as the company confirmed that its earlier North Platte-1 exploratory well encountered over 550 net feet of oil pay in multiple high-quality Inboard Lower Tertiary reservoirs.
North Platte is located in 1,341m (4,400ft) of water on the Garden Banks 959 block and was drilled to a total depth of around 10,515m (34,500ft).
And there’s a third major US Gulf find just announced as Chevron has just struck oil just 19km (13 miles) from Shenandoah.
Chevron said the Walker Ridge block 98 well in the Coronado prospect encountered more than 130m of net hydrocarbon pay.
“This has been a remarkable week, with back-to-back deepwater discoveries in the Gulf of Mexico,” said Bob Daniels, Anadarko’s senior VP for worldwide exploration.
“Initial data indicates the Shenandoah discovery has reservoir properties that appear to be of much higher quality than industry has seen previously in the emerging Lower-Tertiary play.
“The success of this well and our recent Heidelberg discovery further confirms the value of Anadarko’s extensive acreage position.”
Transformed Venari’s CEO, Brian Reinsborough said: “Between the Coronado discovery, the potentially giant Shenandoah discovery, and our recent high bids on remaining open blocks in the Shenandoah/Coronado mini-basin, Venari is firmly positioned for significant growth in a future production hub in the Gulf.”
Cobalt’s chairman and CEO, Joseph Bryant, said: “The exceptional results of both the Shenandoah-2R appraisal well and the North Platte-1 exploratory well further substantiate our regional model of the prolific potential of the Inboard Lower Tertiary Trend.
“We believe that our material working interests in these two significant Inboard Lower Tertiary fields will be the source of tremendous value for our shareholders. Our deep portfolio of prospects on trend with these two fields bodes well for our future growth in the Gulf of Mexico.
Meanwhile Cobalt is cracking on with drilling its Ardennes-1 exploration well on Green Canyon 896. Ardennes is targeting both Miocene and Inboard Lower Tertiary reservoirs. Results are expected sometime mid-year 2013 and analysts are predicting some 500million barrels oil equivalent, with a possible considerable upside.
Chevron holds a 40% working interest in Walker Ridge block 98 and is the operator of the Coronado discovery. Other interest holders are ConocoPhillips with 35%, Anadarko 15% and Venari with 10%.
Anadarko and Conoco each hold 30% of Shenandoah, while Cobalt has 20% and Marathon and privately-held Venari both hold 10%.
Cobalt holds 60% of North Platte while Total owns the balance of 40%.