The country's longest coal bed methane pipeline has finished construction under the trunk channel of the South-to-North Water Diversion Project on Wednesday, its operator said. It's now one step closer to the operation of the pipeline, according to China United Coalbed Methane Corp.

The major part of the 623-kilometer Shenmu-Anping coal bed methane pipeline, the Shanxi-Hebei section, will be put into operation this year. About 200 million cubic meters of natural gas can be supplied to North China this winter, said China United Coalbed Methane Corp, a subsidiary of China National Offshore Oil Corp.

The operation of the pipeline will help ensure the country's gas supply during the upcoming heating season, said Hu Senlin, director of China United Coalbed Methane Corp.

The gas pipeline that connects Shenmu in Shaanxi province and Anping county in Hebei province is designed to transmit 5 billion cubic meters of gas each year.

The cross-region pipeline aims to help boost the development of coal bed methane, a form of natural gas extracted from coal beds.

"The entirety of the line will further enhance winter gas supplies, delivering coal bed methane from Shaanxi to Hebei. Coal bed methane is an important source of unconventional gas, accounting for 5 percent of the total gas supply in China," said Li Ziyue, an analyst with BloombergNEF.

Significant results have been seen in terms of global oil and gas exploration as well as in unconventional gas including shale gas and coal bed methane, according to the National Energy Administration.

Pipeline transport is also increasingly becoming a preferred means of fuel transport due to its low transmission cost, low accident risk and environmental friendliness.

CNOOC has also been stepping up oil and gas exploration to help ensure the country's domestic energy security.

It announced the discovery of a large oilfield in Bohai in September, the Kenli 10-2 oilfield, the appraisal well of which is estimated to produce approximately 569 barrels of oil per day, the company said.

Wang Dongjin, chairman of CNOOC, said the company will make the discovery of large and medium-sized oil and gas fields a priority and continue to deepen geological understanding and technological innovation. The company will also actively promote the increase of oil and gas reserves and production and contribute to the company's high-quality development, he said.