Petroleum Development Oman (PDO) has extended the deadline for prequalification of contractors competing for up to $7bn in contracts to work on the country’s oilfields.

In a statement on its website, the state-run company said that it had extended the deadlines for companies to submit paperwork for qualification to 12 August, from 28 July.

The company said that it had moved the dates to allow more time to evaluate bids after receiving a higher volume than expected.

There are four contracts on offer: two each on fields in the country’s north and south.

One contract in each area covers engineering and maintenance at the fields, each with annual turnover of up to $200m.

The two other contracts, worth up to $150m a year, cover work offsite from the oilfields.

The deals have a duration of seven years, with an option to extend for three further years.

Oman has spent heavily on new technology to enhance oil output from its old, depleted fields and aims to boost total crude and oil condensate output to 805,000bpd this year.