exercise its option to cancel the fourth year of the agreement and revert to the original day rate of approximately $0.6 million per day and original agreement end date of November 2017. KEV made a rate recovery payment of approximately $48.1 million based on this election. In November 2017, we entered into a drilling rig contract for the ENSCO DS-12 which includes one firm well plus six well options. We have completed the initial well and have exercised one of the six well options which will be drilled in 2018. Kosmos-BP Strategic Exploration Alliance During the second quarter of 2017, we formed the Kosmos-BP Strategic Exploration Alliance (‘‘Alliance’’). This Alliance broadens the relationship that previously covered new venture opportunities in Mauritania, Senegal and The Gambia to create an Atlantic Margin explorer-developer partnership. The Alliance will leverage our regional exploration knowledge and capability together with BP’s deepwater development expertise to execute a selective, joint frontier and emerging basin exploration strategy in the Atlantic Margin. Cote d’Ivoire In December 2017, as part of our Alliance with BP, we entered into petroleum contracts covering Blocks CI-526, CI-602, CI-603, CI-707 and CI-708 with the Government of Cote d’Ivoire. We have a 45% participating interest and are the operator in all five blocks. BP has a 45% participating interest in the blocks and the Cote d’Ivoire national oil company, PETROCI Holding (‘‘PETROCI’’), currently has a 10% carried interest. The petroleum contracts cover approximately 17,000 square kilometers, with a first exploration period of three years. The first exploration period work program includes a 12,000 square kilometer 3D seismic acquisition across the five blocks. Strategic entry into Equatorial Guinea Ceiba Field and Okume Complex Acquisition In the fourth quarter of 2017, through a joint venture with an affiliate of Trident, we acquired all of the equity interest of Hess International Petroleum Inc., a subsidiary of Hess, which holds an 85% paying interest (80.75% revenue interest) in the Ceiba Field and Okume Complex assets. Under the terms of the agreement, Kosmos and Trident each own 50% of Hess International Petroleum Inc. Hess International Petroleum Inc. was subsequently renamed Kosmos-Trident International Petroleum Inc. (‘‘KTIPI’’). Kosmos is primarily responsible for exploration and subsurface evaluation while Trident is primarily responsible for production operations and optimization. The transaction expands our position in the Gulf of Guinea and provides immediate cash flow through existing production with potential to increase existing production and also provides step-out exploration opportunities with potential low cost tie-back through existing infrastructure. The gross acquisition price is $650 million effective as of January 1, 2017. After post closing entries Kosmos paid net cash of approximately $231 million, with a combination of cash on hand and availability under the Facility. The transaction is accounted for as an equity method investment. Exploration Blocks In October 2017, we also entered into petroleum contracts covering Blocks EG-21, S, and W with the Republic of Equatorial Guinea. Ratification of the petroleum contracts by the President of Equatorial Guinea is expected in early 2018. We presently have an 80% participating interest and are the operator in all three blocks, but pursuant to an agreement with Trident, we expect to assign a 40% participating interest in the blocks to an affiliate of Trident after ratification. The Equatorial Guinean national oil company, Guinea Equatorial De Petroleos (‘‘GEPetrol’’), currently has a 20% carried participating interest during the exploration period. Should a commercial discovery be made, 79