Since the beginning of this century,revolutionary progress has been made in the understanding of resources and in the mining technologies of the oil and gas industry.Advances in petroleum engineering technology represented by horizontal wells and large-scale fracturing have promoted the scale development of low-grade and unconventional oil and gas resources.After the rapid growth of natural gas production in China for more than 10 consecutive years,the replacement of conventional natural gas resources has been weak and unconventional natural gas has become the major force for increasing production.Coal based SNG(synthetic natural gas) has also become a major competitor in the domestic market.The development of CTL (coal-toliquids) and SNG industries has brought coal resources into the oil and gas product market,expanding the concept of traditional oil and gas resources.The continuous improvement of petroleum engineering technology has promoted the development of deep underground coal gasification technology,which has given economic value to the huge amount of deep coal resources that are unable to be exploited by underground mining,and provides a tremendous resource guarantee for the sustainable development of the traditional oil and gas industry.A preliminary calculation shows that deep underground coal gasification has a competitive advantage in cost compared with high-cost,low-grade,unconventional gas and coal-based natural gas.Deep underground coal gasification is a typical cross-disciplinary and cross-sectoral sophisticated technology.Domestic oil and gas enterprises have dominant advantages in the engineering technology of this field.Further technical integration innovation and multi-industry joint research are needed to eventually realize the commercial application of this deep underground coal gasification technology.