"Fertile Field" in 2,000-meter-high strata: China discovers its first 100 billion cubic meter deep coal seam gas field

China National Offshore Oil Corporation announced on October 23 that China's first 100 billion cubic meter deep coalbed methane field, the Shenfu deep coalbed gas field, was discovered in the 2,000-meter strata on the eastern edge of the Ordos Basin, with proven geological reserves exceeding 110 billion cubic meters.

On October 23, CNOOC announced the discovery of China's first 100 billion cubic meter deep coalbed methane field - Shenfu Deep Coalbed Gas Field. The picture shows the fracturing site of the first deep coalbed demonstration well platform of Shenfu Deep Coalbed Gas Field. Source: CNOOC

Coalbed methane refers to natural gas stored in coal seams. The industry usually refers to coalbed methane buried more than 1,500 meters deep as deep coalbed methane. It is understood that China's coalbed methane resources buried within 2,000 meters exceed 30 trillion cubic meters, of which deep coalbed methane resources account for about one-third.

The Shenfu deep coal seam gas field discovered this time is located in Yulin City, Shaanxi Province, on the eastern edge of the Ordos Basin. The coal seam is mainly buried at a depth of about 2,000 meters, with a single layer thickness ranging from 6.2 meters to 23.3 meters, and an average gas content of 15 cubic meters per ton of coal. CNOOC has currently deployed more than 100 exploration wells in the area, with the highest daily production of a single well reaching 26,000 cubic meters.

As the burial depth increases, the formation temperature, pressure and stress will increase significantly, the reservoir formation mechanism and enrichment law of coalbed methane will become more complicated, and the difficulty of exploration and development will continue to increase. For a long time, China's coalbed methane exploration and development has mostly focused on shallow coal seams with a burial depth of less than 1,000 meters. Due to the lack of supporting process technology, deep coal seams over 1,500 meters have long been regarded as exploration restricted areas.

In response to the problem of increasing deep coalbed methane production, China National Offshore Oil Corporation changed its thinking on the basis of conventional coalbed methane exploration and development, applied ultra-large-scale fracturing technology, continuously optimized fracturing and production processes, and summarized and formed a deep coalbed development technology system suitable for the Shenfu block. In just one and a half years, it successfully discovered a deep coalbed methane field with a geological reserve of over 100 billion cubic meters.

Xu Changgui, deputy chief engineer of exploration at CNOOC, introduced that the discovery of the Shenfu deep coalbed methane gas field demonstrated the broad prospects for the exploration and development of deep coalbed methane reservoirs on the eastern edge of the Ordos Basin, and has important guiding significance for resource exploration and unconventional oil and gas reserve and production increase in similar basins in China.

Planning and production

Source: Guangming.com

Editor: Bai Li