Elaine Maslin reports on the year’s top discoveries to date. The largest discoveries were smaller in 2016, but the average ranged between 396-524 MMboe.
Atwood Oceanic’s Atwood Achiever drillship, which has been drilling for Kosmos.Photo from Atwood Oceanics.
Despite continued cutbacks in exploration spending, operators large and small have continued to drill in 2016, but average find sizes have fallen.
The size of the finds pale compared to last year (Zohr, offshore Egypt, was 3960 MMboe and Ahmeyim, Mauritania, was 1408 MMboe). The average size of a find in last year’s Top 10 was 700 MMboe. This year, it’s 524 MMboe – or 396 MMboe if you don’t include Tulimaniq, the biggest find so far this year.
OE pondered whether to include Caelus Energy’s massive Tulimaniq discovery in Smith Bay on the North Slope, Alaska, in the Top 10 offshore discoveries for 2016. Technically, it’s offshore – sitting in <2m water depth. However, for a large part of the year this is frozen over, drilling is from a land rig and production would likely be from man-made islands. Given its size, we decided to include it and let our readers decide.
Five of the top 10 biggest discoveries up to 11 November have been in West Africa. Discounting the Talimaniq discovery, the top two finds were in Senegal, discovered by the same operator, Atlantic Margin expert Kosmos Energy – which describes Mauritania/Senegal as “potentially the largest new petroleum system opened on the Atlantic Margin. Kosmos is planning a second exploration phase in this area, but outboard of existing discoveries, starting mid-2017, targeting oil. Another operator, Cobalt, found a further two of the Top 10 finds, in Angola.
The rest were in the Gulf of Mexico, Mexico, Egypt and Myanmar. East Africa and the Eastern Mediterranean are notable by their absence, having been high on the list in previous years.
Despite the Tulimaniq outlier, and majors not having a strong show in the Top 10, deepwater remained the focus of most exploration. Gas finds, while not as dominant as last year, thanks to the massive Zohr find offshore Egypt, also remains a significant part of this year’s new resources.
This table will also likely change as we go into 2017 and more is learned about some of the already found resources and wells, still being drilled, complete. Resource estimates for Total’s Raya well, for example, are yet to make it into the public domain. The well, drilled offshore Uruguay, broke records for deepwater drilling.
Part of the Greater Tortue Complex, the Guembeul-1 exploration well encountered 101m of net gas pay in two “excellent quality” reservoirs, including 56m in the Lower Cenomanian and 45m in the underlying Albian. Importantly, Kosmos says, Guembeul-1 demonstrated reservoir continuity as well as static pressure communication with the Tortue-1 well in the Lower Cenomanian, suggesting a single, large gas accumulation. Guembeul-1 was drilled approximately 5km south of Tortue-1, which is expected to be the anchor for a development hub. The Tortue development concept is currently a near-shore FLNG concept.
Sitting in the Cayar Offshore Profond block, about 65km northwest of Dakar in nearly 1800m water depth, the Teranga-1 well was drilled to a total depth of 4485m. The well encountered 31m of net gas pay in good quality reservoir in the Lower Cenomanian objective.
Well results confirmed that a prolific inboard gas fairway extends about 200km from the Marsouin-1 well in Mauritania through the Greater Tortue area on the maritime boundary to the Teranga-1 well in Senegal, Kosmos says.
The Owowo-3 well encountered about 140m of oil-bearing sandstone reservoir. Owowo-3 extends the resource discovered by the Owowo-2 well, which encountered about 157m of oil-bearing sandstone reservoir, according to Exxon.
Owowo-3 was drilled to 3173m in 576m water depth. Exxon says that the Owowo field spans portions of the contract areas of Oil Prospecting License 223 and Oil Mining License 139.
The Thalin-1A exploration well, drilled about 60km west of the Daewoo-operated producing Shwe field, in Block AD-7 in the Rakhine Basin intersected a gross gas column of about 64m. About 62m of net gas pay was interpreted within the primary target interval.
Block AD-7 is in the Bay of Bengal, approximately 100km offshore of the west coast of Myanmar. Water depth at the Thalin-1A well location was 836m.
The well reached a total depth of 3034m. The discovery followed an earlier gas discovery by Woodside at the Shwe Yee Htun-1 well in Block A-6, but Thalin proved a working petroleum system and a new play type different to that encountered at Shwe Yee Htun-1.
“The logical development option for the Thalin-1A discovery is a tieback to the nearby Shwe field,” said Woodside CEO Peter Coleman, earlier this year. “Our strategy is to fully appraise the discovery in one campaign, thereby facilitating concept select in 2017.”
Woodside is currently the largest acreage holder in the offshore Rakhine basin with interests in six blocks. The six permits make up about 47,000sq km and represent 20% of Woodside’s global exploration acreage.
Golfinho was Cobalt’s final exploration well commitment on Block 20 offshore Angola. The firm said initial analysis of the Golfinho well results indicated potential for another large mound feature with Cameia-like fluid and reservoir properties. Cobalt is currently marketing its Angolan assets.
2016's Top 10 offshore discoveries
|Discovery||Location||Water Depth||Operator||Resource (MMboe)|
|Smith Bay, North Slope, Alaska||<2m||Caelus Energy||1800|
|Guembeul||St. Louis Offshore Profund Block, Senegal||2700m||
|Cayar Offshore Profond, Senegal||1800m||Kosmos Energy||880|
|Thalin||Bay of Bengal||836m||Woodside||266|
|Golfinho||Kwanza Basin, Angola||1330m||Cobalt||244|
|Nobilis||Perdido Fold Belt, Mexico||3000m||Pemex||203|
|Zalophus||Kwanza Basin, Angola||1760m||Cobalt||188|
|Fort Sumter||Mississippi Canyon, Gulf of Mexico||2152m||Shell||125|
|Baltim South West||Nile Delta, Egypt||25m||Operated by Petrobel (JV between Eni and Egyptian General Petroleum Corp.), 50/50 owned by Eni/BP||111|
Data from Wood Mackenzie, as of 11 November 2016.
*While offshore, Tulimaniq is in very shallow water (<2m), drilled using a land rig from the frozen ice during winter and likely to be developed using man-made islands, so it’s our find number zero, hence there being 11 finds in this Top 10 table.
*Exxon said 500 MMbbl-1 billion bbl recoverable resource.