Oil giant Saudi Aramco will be listed locally and abroad in the second half of 2018, and the process is going according to plans, Chief Executive Amin Nasser said on Monday.

The IPO is the centerpiece of the Saudi government's ambitious plan, known as Vision 2030, to diversify the economy away from oil. Up to 5 percent of the world's largest oil producer is likely to be listed on both the Saudi stock exchange in Riyadh and on one or more international markets.

"We have always said the listing will happen in the second half of 2018, everything is going very smoothly, we are evaluating different stock exchanges," Nasser, speaking at an industry conference in Bahrain, said.

"There is a lot of work which is ongoing but everything is going as planned," he added.

He said the listing would be "locally on Tadawul and internationally on one or perhaps two" bourses. The Tadawul is Saudi Arabia's stock exchange.

"We are evaluating different stock exchanges globally and we will present this to our board and shareholder on where Aramco will be listed," he added.

Nasser also said an overhang in world oil supplies was expected to ease in the first half of 2017 and that the industry needed to maintain investments for the long term despite lower prices.

When Chinese Alibaba went to public offering in 2014, it secured a revenue of $25 billion. Upon the IPO of Alibaba, the company sold almost 15 percent of its shares and the total value of shares reached $168 billion. Analysts foresee that after selling 5 percent of its shares, Aramco will secure $100 billion, with the company's value reaching $2 billion - and outperforming Alibaba's IPO.