The company, 60 percent owned by Petrovietnam, is valued at around US$1.2 billion based on its share prices on the unofficial market of between VND194,000 and VND202,000 ($12-$12.5).
It offers engineering services for oil and gas exploration, logistic and port services for other oil firms operating in Vietnam and supplies labor to the energy sector.
PTSC said it had a fleet of 20 vessels, one of them a floating production, storage and offloading vessel.
It had revenues of $270 million last year, the company said on its Web site (www.ptsc.com.vn), but gave no comparison or any results for this year.
Petrovietnam is equitizing subsidiaries to raise funds for oil and gas exploration off Vietnam, the third-largest producer of crude oil in Southeast Asia. Crude oil is Vietnam's largest export earner.
PTSC would be the second Petrovietnam subsidiary to float shares this month after Petrosetco, which started trading on the Ho Chi Minh Stock Exchange, Vietnam's main stock market, on Wednesday.
PTSC would become the 91st firm listed on the Hanoi stock exchange after the Sai Son Cement Company, which is scheduled to make its debut on Sept. 19.
Hanoi's market capitalization is around $5 billion, compared with the $14.8 billion of the main exchange in Ho Chi Minh City.