Abstract:

High-water-production gas wells experience significant wellbore pressure loss. During production, pressure decline can cause the liquid droplets in the wellbore to fall back and accumulate, forming slug flow. This leads to increased wellbore pressure drop, elevated bottomhole flowing pressure, and reduced production differential pressure and gas production, ultimately resulting in water flooding and production stoppage. Conventional processes such as foam drainage and plunger lift fail to meet the long-term stable drainage requirements of high-water-production gas wells. To this end, an adaptive intelligent drainage and production process for high-water-production gas wells was designed and developed. Guided by the gas-liquid two-phase flow pattern diagram, the downhole gas-liquid separator and distributor were used to reasonably distribute the gas and liquid produced in the formation in the wellbore, maintaining the wellbore gas and liquid flow velocity within the range of annular mist flow. This prevented liquid fallback and slug flow formation, thereby ensuring stable annular-mist flow drainage in the wellbore. An anti-freezing and blocking system and a gas-liquid management platform were designed to ensure the efficient operation of the process. Additionally, an intelligent control system was established to monitor the production status of gas wells in real time and dynamically optimize the gas-liquid production ratio. Well Q1 in Dongsheng gasfield was selected as the experimental well for process application evaluation. The results showed that after the implementation of this process, the average daily gas production was 6 456 m³, an increase of 15.9% compared to that before implementation, and the daily liquid production was 2.64 m³. The production uptime rate increased from 95.3% to 100%, and the pressure monitoring indicated no liquid accumulation in the wellbore. After continuous operation for six months, the process effectively replaced the foam drainage process and gas lift auxiliary drainage measures. Compared with the period before the experiment, the amount of foam drainage agent and gas lift frequency were reduced, resulting in a cost saving of 507 200 yuan. These findings demonstrate the effectiveness and economic efficiency of the proposed technology. This study solves the problems of short liquid accumulation cycle and difficulty in maintaining stable production in high-water-production gas wells. It holds significant implications for reservoir production capacity enhancement, intelligent control of gas wells, and long-term efficient drainage and gas production throughout the entire life cycle.

Key words: high-water-production gas well, drainage and gas recovery technology, adaptive drainage and production, intelligent drainage and production, Dongsheng gasfield