For some time, it's appeared that China was intent on gobbling up as much of the world's oil as possible. Within the past couple of years, it's flashed its ample checkbook and made deals for black gold with the likes of Brazil, Venezuela, Kazakhstan, and Angola. And for a while, Cnooc (NYSE: CEO) appeared ready to battle ExxonMobil (NYSE: XOM) for a stake in the big Jubilee field of offshore Ghana.

Now, however, it seems that the big country's sights have been diverted somewhat in the direction of the technology needed to produce natural gas from unconventional sources. Last week PetroChina (NYSE: PTR) reached a $5.43 billion deal with Canada's Encana (NYSE: ECA) for the development of remote and difficult-to-reach gas reserves. The two companies will divide both the costs and the profits involved in developing gas from shale and deep wells in Cutback Ridge, which straddles British Columbia and Alberta.

The area -- which comprises 635,000 acres -- is thought to contain proven reserves in the vicinity of 1 trillion cubic feet, and currently produces about 255 million cubic feet of natural gas per day. Encana is one of the major leaseholders North America with licenses covering about 11.7 million acres in Canada and the United States.

Prior to the new deal, Cnooc and Chesapeake Energy (NYSE: CHK) reached an agreement on a shale-gas deal in January. By teaming up with and gaining technical expertise from the North American companies, the Chinese apparently hope to gain the expertise to satisfy more of their energy needs in their home country. Last month, Hess (NYSE: HES) inked a pact with Sinochem Group and China Petroleum & Chemical Corp. to aid in developing China's shale reserves.

According to those who have studied the geology involved in unconventional gas production in China, however, the country's shale plays may be less prone to development than those in North America. In the Asian country, the reserves are widely separated, or located in populated areas. Further, some are older or denser, and potentially less susceptible to the sort of technology that has been used effectively in the U.S. and Canada.

Nevertheless, Chinese authorities hope to increase the share of their total energy represented by natural gas to 10% by 2030, due in part to the heavy pollution that plagues much of the country. At the same time, PetroChina intends to spend $1.5 billion on coal bed methane projects during the next decade.

From an investment perspective, playing the Chinese gas buildup currently presents some challenges. From my perspective, the optimum approach involves acquiring shares in Encana, given its newly signed deal with PetroChina and its sizable North American acreage position.