About 60 percent of the two-year budget will be spent on upstream exploration, with the rest used in the firm's renewable business, newly-appointed president Chaiwat Kovavisarach told reporters on Tuesday.
Bangchak, like other oil refiners, has been hit by a plunge in oil prices, further diversifying into bio-fuel and solar power to minimise risk from the refinery sector.
It also acquired about 80 percent of Australian oil and gas explorer Nido Petroleum Ltd in 2013 to secure energy supplies.
Bangchak is keen to join bidding for petroleum concessions in Thailand and is in talks to buy petroleum fields in the Gulf of Thailand and South China Sea that are expected to conclude later this year, Chaiwat said.
The firm plans to raise its refining capacity to 105,000 barrels per day (bpd) in 2015 with an estimated average refining margin at about $6 per barrel to $7 per barrel.
The company's 120,000 bpd refinery had an average crude run of 86,480 bpd in 2014, down from 99,340 in 2013 due to annual maintenance, it said.
Meanwhile, it plans to raise the capacity of its renewable power plants by 300 megawatts over the next two years, while more than doubling its bio-diesel production capacity to 810,000 litres per day, it said in a statement.
The company expects core earnings before interest, tax, depreciation and amortisation (EBITDA) of 10.4 billion baht in 2015, rising to 25 billion baht in 2020, the statement said.
Its EBITDA stood at 5.16 billion baht in 2014, down 45 percent from the year before as its refinery business was hit by the weak oil prices. But EBITDA from its solar power business rose 85 percent.