Sinopec, CNOOC and Saudi Aramco are in talks to buy a 30 percent stake worth US$2.2 billion in oilfield services company Frac Tech International, according to sources with knowledge of the matter, Reuters reported Wednesday.

Frac Tech helps exploration and production companies perform "fracking" – hydraulic fracturing – jobs and produces equipment and materials. Sinopec and CNOOC will benefit from key technologies of shale gas exploration if the deal goes through.

Frac Tech was also in advanced talks with Saudi Aramco, Spain's Repsol-YPF SA and Sinopec to establish three separate fracking joint ventures in the Middle East, Argentina and China, the sources said on Wednesday.

China has 1,275 trillion cubic feet (about 36.1 trillion cubic meters) of exploitable shale gas, outstripping the United States, according to a 2011 report by the U.S. Energy Information Administration. China finished its first auction for domestic shale gas blocks in July, with Sinopec winning one of the two blocks offered.

China's business press carried the story above on Thursday.