The figures come from analytics firm GlobalData, which says that average capex of of $17.8 billion a year will be spent on 336 oil and gas fields in South East Asia between 2018 and 2020.
Capex on South East Asia's traditional oil projects will add up to $8.3 billion over the three-year period, while heavy oil fields will require $1.7 billion over the same period.
Shallow water projects will be responsible for over 63% of the $46.3 billion, or $31.1 billion by 2020. The onshore projects will be responsible for over 12% or $5.8 billion, while the figure for deepwater and ultra-deepwater will be $9.4 billion.
Petroliam Nasional Berhad will lead the way, investing $7.5 billion into the region's upstream projects by 2020. PT Pertamina (Persero) and Chevron Corporation will follow with $4.3 billion and $3.1 billion respectively up to 2020.
Tangguh, a producing conventional gas field in Indonesia will lead capital investment with $5.2 billion for the LNG expansion project operated by BP Berau.
Block B Gas Development, a planned conventional gas field connected to power plants in Vietnam, follows with capex of $3 billion, which is managed by Vietnam National Oil and Gas Group.
Block H Gas Development Project, a planned conventional gas field feeding an FLNG vessel in Malaysia, will follow with $2.9 billion. Murphy Exploration and Production Company is the operator of the upstream part of the project. Among these three fields, two are shallow water and one is deepwater development.