我国煤层气高效开发关键技术研究进展与发展方向

"十三五"期间,围绕"突破煤层气单井产量低"这一制约我国煤层气高效开发的重大难题,借助国家科技重大专项和其他技术攻关研究,煤层气勘探开发理论认识和工程技术都取得明显进展,表现在4个方面:(1)勘探理念从寻找富集甜点区向高产甜点区转变,开发部署由平铺式到精细化调整转变.(2)围绕高效增产技术方面,在实现由二维地震向三维地...

Research progress and development direction of key technologies for efficient coalbed methane development in China

During the 13th Five Year Plan period, the major problem of the low output of a single well of coalbed methane (CBM) has restricted the efficient development of CBM in China. Through Major National Science and Technology Projects and other technical researches, significant progress has been made in the theoretical understanding and engineering technology of CBM exploration and development. It is manifested in four aspects as follows. Firstly, the exploration concept has changed from looking for rich dessert areas to high-yield dessert areas, and the extensive development deployment has become finer. Secondly, in terms of efficient stimulation technology, with the expansion from two-dimensional seimic to three-dimensional seimic and from vertical wells (cluster wells) to horizontal wells, a new series of fracturing stimulation technologies for coal reservoirs transformation are developed, including indirect fracturing of crushed soft coal, multi-cluster acid fracturing of few sections of horizontal wells applied to calcite filled deep coal seams, and ultra-large-scale limit fracturing of horizontal wells in ultra-low permeability deep coal seams. These technologies have preliminarily solved the problem of economic benefit development of structural coal CBM, broken through the bottleneck of fracturing technology in coal seams with a depth of more than 2 000 m, and promoted the extension of CBM development from medium-shallow layers to deep layers. Thirdly, in terms of drainage and production technology, key technologies such as quantitative drainage and production multi-objective optimization design, CBM well rodless lifting and negative pressure drainage technology have been developed, promoting the transformation of CBM drainage and production control from qualitative to semi-quantitative and quantitative, solving the drainage and production problems of integrated cluster well groups and downward inclined horizontal wells, and effectively improving the production of single wells and the recovery rate of CBM. At last, in terms of stable production and stimulation technology, the innovative technologies are proposed, including stress release gas production of large-diameter horizontal wells and controllable temperature nitrogen injection displacement and stimulation of CBM, which provides technical reserves for the secondary development of CBM. In view of the stage characteristics of China’s CBM industry in the “climbing period” and “strategic opportunity period”, and the goal of the “carbon peak and neutrality”, based on the technical problems that need to be solved, this paper puts forward the “two-step” development strategy of China’s CBM industry. (1) By 2025, breakthroughs will be made in theory and technology, reaching the national target of 10 billion cubic meters per year in the 14th Five Year Plan, and strengthening confidence in industrial development. (2) By 2030, applicable technologies for different geological conditions in China will be formed, reaching the target of annual output of 30 billion cubic meters, and becoming an important part of natural gas production. The corresponding countermeasures are as follows. From the perspective of technology and management, according to the five elements of resources, technology, talents, policy and investment, and in line with the principle of “technological breakthrough as the core, five in one and collaborative innovation”, supporting safeguard measures are studied, formulated and implemented. Moreover, from the two aspects of efficient development and increasing the output of single well, theoretical research and technical research directions in nine aspects related to the future development of CBM industry are put forward, so as to achieve the goal of realizing the high-quality development of national CBM industry.