Allen & Overy (A&O) and King & Spalding have taken lead roles on the £660m merger of drilling contractors KCA Deutag and Dalma Energy.

Aberdeen-headquartered KCA Deutag has agreed to merge with Oman-based Dalma Energy, a deal that will create a combined company operating 100 rigs across Africa, Europe, Russia, the Middle East, the Caspian Sea, Southeast Asia and the Americas.

A&O is advising KCA Deutag, with London corporate partner David Broadley in the lead role. The magic circle firm's team also includes finance partners James Graham and Kevin Muzilla.

Broadley is also part of the A&O team currently advising 21st Century Fox on UK corporate aspects of Disney's acquisition of most of the company's assets, in a deal valued at about $52.4bn. He has advised on a number of other high-profile matters in recent years, including payment processing group Worldpay's 2015 initial public offering.

Meanwhile, King & Spalding is advising Dalma. The US firm's team is being led by Middle East managing partner Jawad Ali, Abu Dhabi Islamic finance partner Simon Rahimzada and finance and capital markets partner Rizwan Kanji in Dubai.

A number of the firm's London lawyers have also been working on the deal, including corporate partner Ilan Kotkis, tax partner Daniel Friel and employment partner Jules Quinn.

Other firms to have worked with KCA Deutag in the past include Pinsent Masons, which in 2012 advised its parent company Abbot Group on a £5.6m Bribery Act settlement, in what was the first case involving self-reporting by a company under the legislation.