KUALA LUMPUR: Yang di-Pertuan Agong Al-Sultan Abdullah Ri'ayatuddin Al-Mustafa Billah Shah witnessed the signing of a historic agreement between PETRONAS Abu Dhabi Sdn Bhd, a wholly-owned subsidiary of PETRONAS, and Abu Dhabi National Oil Company (ADNOC) to explore and appraise Unconventional Onshore Block 1, covering a 2,000 sq km concession in the Al Dhafra region.