Abstract: Multi-lateral horizontal wells are one of the efficient development methods for coalbed methane, with high production potential. This study selects the Bijie area in Guizhou Province as the research object. This region is rich in coalbed methane resources, with considerable geological reserves. The overall structure is relatively simple, and there are no major fault zones developed. It has typical geological characteristics for coalbed methane development. To explore the suitable lateral well types for the Bijie area, this paper establishes a numerical simulation model of coalbed methane based on the Petrel software. It studies the production capacity influence laws of two typical multi-lateral well types, namely fishbone-shaped lateral wells and fan-shaped lateral wells, in the development of coalbed methane. During the research process, the influences of key parameters such as lateral angle, lateral length, and lateral spacing on production capacity are mainly investigated. The development effect differences between the two well types are quantitatively evaluated through numerical simulation methods. At the same time, this paper also comprehensively compares and analyzes the differences between the two in terms of drilling difficulty, construction cost, and adaptability. The research results show that within a certain range, the production capacity of fishbone-shaped lateral wells increases with the increase of lateral length, the affected range of lateral wells increases, and the production also increases, but the increase rate decreases to a certain extent. The production capacity of fishbone-shaped lateral wells increases with the increase of lateral angle, lateral number, and well deviation angle. For fan-shaped lateral wells, when the main wellbore angle is 30°-90°, the daily gas production increases with the increase of the angle. The production capacity increases with the increase of lateral length, but the growth rate slows down after reaching a certain level. The production capacity also increases with the increase of lateral angle and number. Fishbone-shaped lateral wells have stronger adaptability in complex geological conditions and can effectively reduce drilling difficulty and construction costs, while fan-shaped lateral wells perform better in increasing single-well production capacity. Therefore, in actual coalbed methane development, it is necessary to comprehensively consider geological conditions, economic costs, and technical levels, and select the appropriate lateral well type to achieve the best development effect and economic benefits. This study provides theoretical basis and practical value for the efficient development of coalbed methane in the Bijie area and similar regions.

Key words: lateral wells, coalbed methane, pressure drop model, production analysis, difficulty of drilling