Abstract: The development of deep coal-rock gas using clustered vertical–deviated wells faces challenges such as unclear controlling factors
for production capacity, and significant differences in single-well production, which restrict the high-efficiency utilization of deep coal-rock gas resources in areas with multi-set thin coal rocks developed. In order to enhance the single-well production, a total of 105 clustered vertical–deviated wells in Daning–Jixian block has been studied to systematically identify the controlling factors for production capacity. Through single-factor analysis, law of production capacity control of 11 geological and engineering parameters has been clarified, among which resource abundance and reservoir fracability are the geological foundation for high-yield production. Furthermore, multivariate linear regression analysis and decision tree model have been combined to identify four engineering controlling factors, i.e., total sand volume, construction pressure, well shut-in period, and post-fracturing assisted fluid flowback volume. On this basis, a cultivation pathway for high-yield wells has been established following the strategy of “deployment optimization–intense reservoir reconstruction–damage control–efficiency enhancement”, and the high-efficiency well development technology system has been developed, centered on collaborative geological and engineering sweet spot zone selection, large-scale volume fracturing and reservoir reconstruction, post-fracturing rapid flowback for filtration control, and multi-source energy coupling assisted drainage and pressure release. In addition, the supporting engineering organization strategies have been proposed, including advanced artificial lifting operation, staged surface engineering construction, and multi-process coordinated execution, forming a lifecycle high-efficiency development mode for clustered vertical–deviated wells. This technology system has been applied to Yichuan well area, obtaining significant achievements, with the average single-well gas rate increased from 0.8×10⁴ m³/d to 1.8×10⁴ m³/d, EUR reaching up to 2000×10⁴ m³, significantly improved reservoir pressure release efficiency, and constantly enhanced steady production capacity. The study results provide systematic technical support for the high-efficiency development of deep rock gas in Yichuan well area and offer a reference path and practical basis for large-scale application of the technology system in similar blocks.

Key words: deep coal-rock gas, clustered vertical–deviated well, controlling factors for high-yield production, cultivation pathway for highyield
wells, technology system for high-efficiency development, engineering organization strategy