(EnergyAsia, September 1) — Petronas together with upstream subsidiary Petronas Carigali Sdn Bhd and Sarawak Shell Bhd recently concluded a gas sales agreement (GSA) with Malaysia LNG Sdn Bhd (MLNG) for the supply of up to 400.4 trillion btu of gas to the MLNG plant until 2020.   The agreement effectively extends a similar earlier…