Progress of coalbed methane exploration and development in China during the 13th Five-Year Plan period and the next exploration direction

Based on survey data of coalbed methane exploration and development projects in China, the production status of coalbed methane fields and scientific & technological achievements, this paper analyzes the comprehensive control technical measures for stable and increasing production of coalbed methane fields, and the geological conditions and potential of deep coalbed methane exploration breakthrough. The coalbed methane horizontal well technology and the matching well pattern optimization and drainage technology are also summarized. The results show that the most effective technical measures for the comprehensive control of stable production of coalbed methane fields and low production wells in China are four types, including adding new production layers, adjusting the development plan to expand the production scale, embedding infill well pattern in horizontal wells, and stimulation technology of old wells. The concept of “coalbed methane horizontal well + technical system” is proposed, that is, the combination system integrates horizontal well drilling and completion, casing staged fracturing, and rodless pump drainage technology, emphasizes on the mutual matching of well pattern optimization deployment, drilling and completion, fracturing technology and drainage technology equipment. The meaning of deep coalbed methane is defined, free gas generally exists in coal reservoir, and the critical depth is affected by formation temperature gradient and pressure. It is pointed out that deep coalbed methane and low rank coalbed methane are the key areas and directions of coalbed methane exploration in the next step.