We are an offshore shallow-water drilling contractor providing worldwide offshore drilling services to the oil and gas industry. Our primary business is the ownership, contracting and operation of jack-up rigs for operations in shallow-water areas (i.e., in water depths up to approximately 400feet), including the provision of related equipment and work crews to conduct oil and gas drilling and workover operations for exploration and production customers. We own 27 rigs, including 26 jack-up rigs and one semi-submersible rig, with an additional eight jack-up rigs scheduled to be delivered by the end of 2020. Upon delivery of these newbuild jack-up rigs, we will have a fleet of 30 premium jack-up rigs, which refers to rigs delivered from the yard in 2001 or later.
We aim to become a preferred operator of jack-up rigs within the jack-up drilling market. The shallow-water market is our operational focus as we expect demand will recover sooner than in the mid- and deepwater segments of the contract drilling market. We contract our jack-up rigs and offshore employees primarily on a dayrate basis to drill wells for our customers, including integrated oil companies, state-owned national oil companies and independent oil and gas companies. During 2018, our top five customers by revenue were subsidiaries of NDC, TAQA, BW Energy, Spirit Energy and Total. During the first quarter of 2019, our top five customers by revenue were subsidiaries of NDC, TAQA, Perenco, Total and Tulip. A dayrate drilling contract generally extends over a period of time covering either the drilling of a single well or group of wells or covering a stated term. Our Total Contract Backlog was $383.2 million as of June 30, 2019 and $377.5 million as of December 31, 2018. We currently operate in significant oil-producing geographies throughout the world, including the North Sea, the Middle East, Mexico, West Africa and Southeast Asia. We intend to operate our business with a competitive cost base, driven by a strong and experienced organizational culture and a carefully managed capital structure.
From our initial acquisition of rigs in early 2017, we have expanded rapidly into one of the world’s largest international offshore jack-up drilling contractors by number of jack-up rigs. The following chart illustrates the development in our fleet since our inception:
As of and for the Six Months As of and for the Year Ended June 30, Ended December 31,2019 2018 2017 Total Fleet as of January 1 27 13 0 Jack-up Rigs Acquired(1)— 23 12 Newbuild Jack-up Rigs Delivered from Shipyards 29 1 Jack-up Rigs Disposed of2 18 0 Total Fleet as of the end of Period 27 27 13 Newbuild Jack-up Rigs not yet Delivered as of the End of Period 89 13 Jack-up Rigs Committed to be Sold as of the End of Period 1— — Total Fleet, including Newbuild Rigs not yet Delivered, as of the end of Period 35 36 26
(1) Includes acquisition of one semi-submersible rig in 2018. ---
Borr Drilling Limited was incorporated by Taran Holdings Limited on August 8, 2016, pursuant to the Companies Act, as an exempted company limited by shares and registered in the Bermuda register of companies with the name “Magni Drilling Limited.” On December 16, 2016, we changed our name to Borr Drilling Limited. Our principal executive offices are located at S. E. Pearman Building, 2nd Floor, 9 Par-la-Ville Road, Hamilton HM11, Bermuda and our telephone number is +1 (441) 737-0152. Our internet address is www.borrdrilling.com.More