Gas extraction hits new depths in Shanxi

Project beginnings

Established in November 2009, the Linfen Gas Production Management Area covers the old revolutionary districts of Daning, Yonghe, Jixian and Xixian counties in Linfen city.

Once deemed too deep for development, these rich coalbed methane resources were found to have significant development potential, accounting for nearly a third of the nation's proven reserves.

The area has become the most important natural gas production base in southwestern Shanxi, empowering the green transformation of traditional coal cities.

Zhang Lei, deputy chief geologist at PetroChina's Coalbed Methane Co, said that 16 new wells have been drilled in the Daji Gas Field this year, adding 250 million cubic meters of new production capacity, pushing daily gas output to over 11 million cubic meters — equivalent to a 3-million-metric-ton oil and gas field.

Research from the company indicates that China's coalbed methane geological resources could reach 50 trillion cubic meters, with the Ordos Basin alone holding over 25 trillion cubic meters.

"The large-scale development of the Daji Gas Field not only enriches the domestic clean energy supply but also effectively increases the natural gas self-sufficiency rate, reducing dependence on foreign sources and contributing to the construction of a strong energy nation," Zhang said.

The gas field's success owes much to the dedication of technical workers. In 2011, coalbed methane expert Sun Junyi and over 30 technical workers settled in the Daning-Yonghe block to commence exploration and development. For 15 years, they persevered on the Loess Plateau, initially targeting shallow coalbed methane at depths of 1,000 meters, only to face challenges of low output and high costs.

"The team broke away from traditional thinking, leveraging high-precision 3D seismic technology to extend exploration from the traditional 1,200-meter shallow layers to depths beyond 2,000 meters, akin to conducting a detailed CT scan of the strata," Sun said.

In 2019, the first coalbed methane well, Daji 3-7, achieved industrial gas flow.

Two years later, the block's newly proven reserves exceeded 112.1 billion cubic meters, and the Daji Gas Field was officially named, filling a global gap in deep coal resource development exceeding 2,000 meters. By December of that year, the Jishen 6-7 well's daily gas output surpassed 100,000 cubic meters, making it the world's first deep coalbed methane well to achieve commercial production at depths exceeding 2,000 meters.

Zhang Gaixia, deputy director of safety at the Linfen Gas Production Management Area, has worked in the field for 16 years, meticulously crafting production plans, inspecting equipment and monitoring operational data with rigor and precision.

"In coalbed methane development, not a single data point can be off," he said. "Since the start of gas supply for last winter's heating season, the pipelines have carried not just natural gas, but also the public's expectations for a warm life."

The gas field has been established as a national demonstration area for deep coalbed methane development, with over 200 horizontal wells producing gas steadily. The natural gas produced not only meets local industrial and living needs but also flows through the West-East Gas Pipeline to the Beijing-Tianjin-Hebei region and North China.

Production manager Chen said,"Gas extraction operations focus solely on gas, not coal, effectively avoiding surface subsidence issues and achieving a win-win for resource development and ecological protection."

The technical team is now tackling challenges to extend coalbed methane wells to reach 6,000-meter ultra-long horizontal sections to improve resource recovery rates and reduce unit development costs.

PetroChina said that by 2035, China's coalbed methane annual production is expected to reach 40-50 billion cubic meters.

Zheng Hongwei and Sun Zhefeng contributed to this story.

Contact the writers at zhuxingxin@chinadaily.com.cn