MELBOURNE, Feb 20 (Reuters) - ExxonMobil Corp XOM.N , Total SA TOTF.PA and their partners in gas projects in Papua New Guinea (PNG) have broadly agreed on how they want to expand the PNG LNG project using gas from new and existing fields, Oil Search Ltd OSH.AX said on Tuesday.
* Set to propose three new LNG trains with total capacity of 8 million tonnes a year
* Two trains for Total-controlled Papua LNG, with gas from Elk-Antelope fields
* Third train to be underpinned by gas from existing PNG LNG fields and P'nyang field
* Decision on front-end engineering and design expected in second-half 2018
* Targeting Northeast and Southeast Asian markets for offtake agreements