Levels of international exploration by mid and large cap companies during the first half of this year fell 28%, according to new industry analysis.

Examining the activities of 40 mid and large cap E&P companies, a report by Richmond Energy Partners asserts that drilling was down 28% in the first half of 2014, and that discovered volumes are down 43% on the same period last year.

“Success rates are being maintained but the average discovery size fell in 1H 2014 to less than 50% of that recorded in 2012, largely due to the maturing offshore gas provinces in East Africa and the Mediterranean,” says the REP study.

While frontier drilling success continues to be “elusive,” REP adds: “The emerging pre-salt play in Angola is currently the hottest emerging play globally.”