Sometimes a new frontier emerges with astonishing speed to become an apparent “overnight” sensation. In the case of East Africa, the region has been extraordinarily transformed in little more than a year from a wildcat deepwater province to a world-class exploration hotspot with major multi-Tcf gas field development plans already in the pipeline.

For at least two decades, any discussion of African upstream potential nearly always took a turn toward the West African coast, where established shallowwater and deepwater reserves have played a part in the investment planning of supermajors and independents alike. Angola, Nigeria, Ivory Coast, and now Ghana have dominated the headlines.

North Africa likewise has been a regular focus for E&P, both onshore and offshore, with activity taking place in Egypt, Libya, Algeria, Tunisia, and others.

East Africa, meanwhile, had slipped off the radar screen of all but a few specialist players and one or two larger and more adventurous independents. Despite a substantial history of onshore and limited offshore exploration and production activity in countries such as Mozambique, Kenya, Tanzania, Uganda, and Madagascar, the area was not believed to be of world-class potential.

That was until more recent studies were undertaken on the deep offshore sectors of Mozambique, Kenya, and Tanzania in particular, as water depths became less of a restricting factor.

Mozambique

Several years ago Anadarko Petroleum began reporting that it had a minimum of 100 exploration leads in the Rovuma basin. Other companies stepped up geophysical activity both onshore and offshore, while specialist players like Dominion Petroleum, Artumas, Aminex, Origin Oil, and Maurel & Prom experienced their own smaller scale successes.

The signs looked good, but there seemed little to pique industry interest until Anadarko and its partners spudded a deepwater wildcat offshore Mozambique early last year.

No one expected Windjammer, the very first wildcat drilled in this frontier, to be a major gas discovery.

East Africa suddenly became a new proposition when details of this discovery were released. The well encountered more than 480 net ft (146 m) of natural gas pay in high-quality reservoir sands, with a gross column of more than 1,200 ft (366 m). Drilled by Fred. Olsen’s Belford Dolphin drillship in 4,800 ft (1,463 m) water depth, the well went on to encounter an additional 76 net ft (23 m) of gas pay. That brought the total net feet of gas pay in Windjammer to more than 555 ft (169 m).

Bob Daniels, Anadarko’s senior vice president, Worldwide Exploration, described Windjammer as a “true rank wildcat” that de-risked a substantial portion of approximately 50 leads and prospects that the company has identified across its 2.6-million-acre position in the basin.

The scale of the Windjammer find and those that followed over the course of 2010 and into 2011 in the Rovuma basin (Barquentine, Lagosta, and most recently Tubarao), have established enough gas reserves in this region for at least one likely floating liquefied natural gas (FLNG) project in the Offshore Area 1 permit offshore Mozambique, for which conceptual commercialization and design studies are already being evaluated. Those studies also include direct subsea-to-shore options.

Windjammer and Barquentine lie 2 miles (3.2 km) apart and around 30 miles (48 km) offshore, and partner Cove Energy has stated that the discoveries found “a substantial multi-Tcf natural gas resource.”

Tubarao also was mentioned specifically because it is in a high-quality Eocene-age reservoir that is separate and distinct from the hydrocarbon accumulations in the three previous discoveries. Daniels said the find opened an entirely new play style as well as showing greater efficiencies, with the well drilled in half the time of the previous probes. The wellbore at Tubarao, 26 miles (42 km) southwest of Windjammer, has been preserved for potential use in future testing.

Oil also has been found in the same area. Around 67 miles (110 km) south of Windjammer, within the same permit, Anadarko and Cove struck oil on the Ironclad prospect, described prior to drilling as a high-risk Palaeocene and Cretaceous prospect. This indicates encouraging oil potential in the south of the block and is particularly significant as it is the first time that hydrocarbon liquids have been found in deep water off the east coast.

The Ironclad-1 wildcat well penetrated 125 ft (38 m) net of oil- and gas-saturated sands in an upper fan lobe. Drilling operations ceased at a total depth of 17,402 ft (5,304 m), the well having penetrated 673 ft (205 m) of targeted Cretaceous-age sediments in two distinct fan lobes.

John Craven, CEO at Cove, said at the time, “This is very promising not just for the Cretaceous fan systems, where more than 80 sq km (31 sq miles) of closure have been mapped, but for additional nearby prospects already identified elsewhere in the Offshore Area 1 block. In addition, the presence of oil and its associated petroleum system in Ironclad is significant for our extensive deepwater blocks in both Mozambique and Kenya.”

But it is the east coast’s gas promise that is catching the upstream industry’s eye at present, especially with the widening technological options for both large- and smaller scale offshore liquefaction solutions now being offered by competing contractors.

Cove has described Mozambique as having sufficient gas for a proposed world-class LNG project, with plans for the area’s further exploration and appraisal accelerated with new 3-D seismic, a dedicated rig, and the addition of a second committed rig scheduled to start drilling in 4Q 2011 through 2013.

Company officials added that 2013 is targeted for LNG project sanction, an ambitious – but achievable – schedule in what is still a largely frontier province.

Other companies also are moving in for a piece of the action, with anticipated drilling later this year by a consortium of ENI, Galp, and Kogas on a block immediately east of the discoveries, with up to three wells planned. Statoil, meanwhile, is planning to drill on a block to the south.

Tanzania

E&P action is quickly moving northward, where BG Group and its partners have widened the play significantly with major deepwater finds offshore Tanzania.

BG already has discovered more than 500 MMboe offshore Tanzania, according to CEO Frank Chapman.

Two discoveries – Pweza and Chewa – so far are “soundly economic as a floating LNG development,” he said. However, the company is focused on further drilling in the territory due to kick off later this year, based upon 1,930 sq miles (5,000 sq km) of 3-D seismic already shot in blocks 1, 3, and 4.

The company recently confirmed its third discovery there, Chaza-1. The find in Block 1 is approximately 11 miles (18 km) offshore south Tanzania in 3,117 ft (950 m) water depth. It is 120 miles (200 km) south of the Pweza and Chewa discoveries.

Chapman believes Tanzania and Mozambique are well positioned to access Asia-Pacific LNG markets.

“We will of course be pursuing further drilling based upon 3-D seismic, and a new drilling campaign based on that data will commence before the end of this year,” Chapman said. “That will be aimed at adding to the current resource tally, with a view to underpinning a land-based, two-train LNG project.”

He went on to describe Tanzania as a completely virgin play, with all manner of different potential targets in different play styles and concepts. One thing that remains unknown at this time, he said, is what level of oil prospectivity exists alongside gas and gas condensate.

“If we take into account the deeper prospectivity and prospectivity further out in deep water, there is considerable testing here to be done. We’ve got our sleeves rolled up, the guys are working up a bit of a sweat, and we’ll see where it goes.”

BG’s partner on Chewa, Ophir Energy, said 1,235 sq miles (3,200 sq km) of 3-D seismic has been acquired over blocks 3 and 4, and a second 3-D survey of 695 sq miles (1,800 sq km) has just been completed in Block 1. A second drilling campaign will begin in late 2011.

Ophir Managing Director Dr. Alan Stein said there were early indications that there could be sufficient volumes of gas present within the company’s acreage off Tanzania “to support the construction of one or more LNG processing facilities, which will allow for the export of gas to world markets.”

The country is currently taking stock of its increased promise, recently delaying a fourth deep offshore bidding round until 2012, according to state oil company Tanzania Petroleum Development Corp. (TPDC).

The bidding round was to have been opened in April 2011 and was expected to include 13 blocks ranging from 3,937 to 11,483 ft (1,200 to 3,500 m) water depth. “The round has been postponed to give more time for preparations,” TPDC said in a statement. “This will include proper demarcation of new blocks using additional new seismic.” So far Tanzania has licensed 12 deepwater blocks.

Companies with exploration blocks in Tanzania, in addition to BG and Ophir, include Artumas Group, Maurel & Prom, Statoil, and Shell.

Ophir, a “first mover” in Tanzania, recently entered into a new agreement with Ras Al Khaimah Gas Tanzania Ltd. (RAKGas) to acquire a 70% interest and operatorship of a production-sharing agreement (PSA) for the East Pande block. The license covers an offshore and onshore area of more than 2,895 sq miles (7,500 sq km) in south Tanzania. The block lies immediately west of blocks 1, 3, and 4 and stretches from onshore to a maximum of 6,562 ft (2,000 m) water depth.

Another independent, Dominion Petroleum, was recently granted a one-year extension to the Initial Exploration Period for its deepwater Block 7 by Tanzania’s Ministry of Energy and Minerals.

The extension to the current period removes any obligation for the company to relinquish any portion of the block until May 2012, providing Dominion with time to more fully evaluate the acreage before a mandatory 50% relinquishment at the close of the Initial Period.

Dominion has one prospect – Alpha – in the block with a mean prospective resource of 7 Tcf of gas. Andrew Cochran, CEO, said, “The extension of the license will allow us to better formulate plans on a drilling program for our deepwater East Africa portfolio in 2012. As the area becomes more and more competitive by the day, our position becomes more and more strategic.”

Kenya

Kenya’s deepwater acreage also is attracting global interest, with play types similar to those in Mozambique along with a more oil-prone petroleum system.

Anadarko and Cove are active here as well, in deepwater blocks L5, L7, L11A, L11B, and L12. Drilling is planned for 2012. Cove recently farmed into the blocks and pointed out that it now has an extensive contract area over the country’s entire deepwater fairway, which is more than three times the size of its Rovuma Offshore Area 1 permit offshore Mozambique.

Cove identified a diversity of hydrocarbon play types, noting that typical deepwater hydrocarbon plays such as turbidite fan/channels are evident in a number of structural and stratigraphic trapping situations from existing seismic data and are similar to those identified offshore Mozambique.

More than 3,045 line miles (5,000 line km) of 2-D seismic has been acquired over the area, with drilling likely to start in 2012/13 following the ongoing Mozambique exploration program.

Craven said the blocks cover most of Kenya’s deepwater acreage. According to Craven, aligning with Anadarko “ensures operational and exploration continuity in our core area of East Africa, with offshore Kenya as a natural follow-on to our active exploration program in Mozambique.”

Cove also has linked up with BG and other partners for exploration blocks L10A and L10B. Operator BG and has signed PSAs for both blocks, firstly with plans to acquire seismic over the acreage in the southern portion of the Lamu basin, which ranges from around 656 ft (200 m) to more than 6,234 ft (1,900 m) water depth.

Dominion Petroleum also is active here, recently being awarded prime deepwater Block L9 in the Lamu basin. The company says the block represents “one of the last, best new licensing opportunities along the whole of the deepwater East African margin,” exhibiting many geological similarities to the company’s Block 7 offshore Tanzania.

Block L9 has one previously drilled well, the Simba-1 well, which was drilled in 1979. That well encountered gas shows in the tertiary and upper Cretaceous. Simba results suggest a working hydrocarbon system in the Lamu basin, and offshore oil seeps have been identified north of L9.

“Kenya’s block L9 represents one of the very few ‘ground floor’ opportunities remaining in the highly prospective and increasingly attractive East African offshore basins,” Cochran said. “The PSC, when signed, will represent a significant expansion of Dominion’s deepwater footprint in an area that is rapidly gaining the attention of major players in the industry.

“Through Dominion’s expansion to offshore Kenya, with a large operated working interest, we’re keeping pace with the industry along the East African margin among companies leading the charge in the region.”

East Africa has for many years been considered something of an exotic exploration province with limited potential. But with at least two FLNG projects under study and several more expected to follow over the course of the next two years, along with the multi-billion dollar development spending that will follow, it has been dramatically transformed.