The well has proven oil charge across a significant part of the Greater Etom structure, Tullow said.

The Yuedong 30-1-1 well hit mostly gas. The well was drilled to a depth of 4,235 m (13,894 ft). The formation has a temperature of nearly 200 degrees C (392 degrees F).

Kosmos Energy, BP, offshore, Senegal, Mauritania, Yakaar-1, discovery, gas, Tortue

The gas find, located west of the Teranga discovery and south of Tortue, is estimated to hold 15 trillion cubic feet of natural gas.

The new discovery was made onshore in the Uzunada area, state news agency TDH said. The test well produced 500,000 cubic meters of gas and 150 tonnes of condensate per day, it said.

Anadarko, the operator, said the well hit 79 m to 110 m (260 ft to 360 ft) net of natural gas pay.

Drilled to a total depth of 2,981 m (9,780 ft) in a water depth of 150 m (492 ft), well B1 16/3 hit gas and condensates in the Metlaoui Group of Eocene age, Eni said.

The Parex-operated Boranda-1 well, drilled to a depth of 3,657 m (11,998 ft) in the Esmeraldas Formation, found crude in four intervals of oil sands with a total thickness of 40 m (131 ft).

ExxonMobil, Guyana, offshore, discovery, oil, Snoek, Liza, Payara

The Snoek well, southeast of the Liza discovery, hit high-quality oil-bearing sandstone reservoirs, the company said.

The Qattameya Shallow-1 exploration well, drilled using the El Qaher II jackup rig, struck 37 m (121 ft) of net gas pay in high quality Pliocene sandstones, the company said.

The well, which is located in Contractual Area 1, hit 110 m (361 ft) of net oil pay from multiple good quality Pliocene reservoir sandstones, the company said in a news release.

The company plans to perform a three- to six-month extended production test starting in third-quarter 2017, following the completion in April of a light oil resource volume assessment, to help determine the commerciality of the discovery.

With 1.2 billion barrels of recoverable light oil, Repsol and Denver-based Armstrong Energy claim the discovery is the "largest U.S. onshore conventional hydrocarbons discovery in 30 years."