Neptune Energy Bonaparte Pty Ltd reduced its interest in the NT/RL1 retention lease, which contains the Petrel discovery, on 2 October 2019. As a result of Neptune Energy divesting some of its share, joint venture participants Santos Ltd, Bonaparte Gas & Oil and Lattice Energy have increased their shares. Santos has also acquired operatorship from Neptune Energy.  Neptune Energy has reduced its holding from 60% to 22.41%, and relinquished operatorship to Santos. Santos has made the biggest increase, now holding 54%, up from 19.49%. Bonaparte Gas & Oil and Lattice Energy have increased their holdings to 17.84% and 5.75% respectively.  The licence contains the east part of the Petrel discovery, which was made in August 1969. It was reported in 1H 2019 that the joint venture was continuing to evaluate development options for the Petrel gas field, with it being considered as part of a wider development project that may involve the Frigate Deep and Tern discoveries.  Neptune entered NT/RL1 in February 2018 by acquiring ENGIE E&P International SA. The deal saw Neptune enter Australia by acquiring 60% interest and operatorship of WA-27-R & WA-40-R (Frigate Deep/Tern fields) and NT/RL1 & WA-06-R (Petrel field). However, on 11 April 2019 Neptune Energy withdrew from WA-27-R and WA-40-R, leaving Santos as sole holder and operator. It has now also reduced its holding in NT/RL1.  NT/RL1, which covers an area of 623 sq km, was awarded on 16 May 1994. On 2 October 2019 it underwent an interest change, with participant holding becoming: Santos Ltd (54% + Operator), Neptune Energy Bonaparte Pty Ltd (22.41%), Bonaparte Gas & Oil Pty Ltd (17.84% and Lattice Energy Resources (Bonaparte) Pty Ltd (.75%).
Santos G&O (->54% op) and Lattice Energy (-> acquired 17,84% and 5,75% WI respectively in the NT/RL1 retention lease, which contains the Petrel discovery, from Neptune Energy (->22,41%)