SINGAPORE, Aug 21 (Reuters) - China's liquefied natural (LNG) gas importers are starting up or expanding trading desks in London and Singapore to better manage their growing supply portfolios in an increasingly volatile global market that doubled in value last year.

Below is a list of China's main gas traders and their operations globally, according to information from company sources and traders.

PetroChina International (PCI)

PCI, a unit of state-owned PetroChina, is China's largest portfolio player of piped gas and LNG, with nearly 100 people including traders, origination and operations personnel, and market analysts staffing trading desks in Beijing, Singapore, London, Dubai and Houston.

PCI is also the most internationalized Chinese trader, with non-Chinese making up about two-thirds of its 17-strong London team, including Senior Vice President Keith Martin, previously an executive with German utility Uniper and Russian gas giant Gazprom.

In May, PCI became the first Chinese firm to gain long-term access to gas storage at a European gas terminal.

Unipec

The trading arm of Sinopec has LNG teams in Beijing, Singapore and London. Its London operation has five staff led by Wang Bingsi, a Unipec veteran and also managing director of Unipec London, with near-term plans to add a trader to focus on the European piped gas market.

CNOOC

CNOOC's gas trading team - part of the gas and power unit of China National Offshore Oil Company (CNOOC), China's first LNG importer and largest by far - is handled via Beijing and Singapore.

CNOOC also plans to create a London desk in the coming year or two, following PCI and Unipec.

Sinochem

The seasoned state oil and chemicals trader started its gas trading desk in Beijing in early 2021 and inked its first long-term LNG purchase deal with U.S. exporter Cheniere that year. The contract allows Sinochem to expand trading to London.

Zhenhua Oil

The subsidiary of state defence giant Norinco started a gas desk in Beijing in 2018 to invest in an LNG terminal and trade the fuel. It owns 34% of a terminal with a capacity of 3 million metric tons a year that is being built in Jiangsu province.

ENN

ENN Natural Gas Co, a subsidiary of ENN Group, is China's first private operator of a major receiving terminal. It's also by far the largest portfolio player among the Chinese city-gas distributors with contracts to take more than 7 million tons of U.S. LNG a year.

Its trading arm, headquartered in Hebei province in northern China with offices in Shenzhen city in the south and in Singapore, hired ex-senior traders from CNOOC, Sinopec and trading house Trafigura

ENN has also recently started hunting for its first trader for its planned London desk.

Beijing Gas

A piped-gas distributor with a monopoly to supply the Chinese capital, Beijing Gas has over the past five years built a Singapore-based trading desk of 12 people, with plans to add a derivatives trader and an operations manager.

Zhejiang Energy

Zhejiang Energy, a state-owned utility backed by the Zhejiang provincial government, secured a 20-year LNG contract with Exxon Mobil in 2019 and more recently sealed a second 20-year contract with Mexico Pacific.

It operates a trading desk in Singapore, and also owns part of a CNOOC-controlled import terminal in Ningbo and has a controlling stake in another terminal in Wenzhou. Both terminals are in Zhejiang province.

China Gas Holding

China Gas, one of China's largest privately controlled piped-gas distributors, is starting up a Singapore office with two traders.

It owns a minority stake in a Beihai regasification terminal in Guangxi province and another in a terminal being built in Yantai of Shandong province. China Gas has signed contracts to take 3.7 million tons of U.S. LNG a year starting in 2026.

JOVO Energy

Privately controlled JOVO Energy owns a 1.5 million ton-per-year import terminal in southern Guangdong province and has trading operations in Guangzhou and Singapore.

JAPAN AND SOUTH KOREA

Other Asia gas importers are also expanding global operations.

JERA, Japan's largest LNG importer, and trading houses Mitsubishi Corp and Marubeni Corp, already have trading operations in London, while Tokyo Gas and South Korea's SK E&S recently set up offices there.

Sumitomo Corp, which has a desk to trade piped gas in London is considering expanding into LNG trading, said a company spokesperson. (Reporting by Chen Aizhu; Additional reporting by Yuka Obayashi in Tokyo; Editing by Florence Tan and Tom Hogue)