Drainage gas recovery technology by tubing perforated gas-lift drainage

The Longgang reef gas reservoir is a high-temperature, ultra-deep, mid-high-sulfur containing gas pool. During production test, most of gas wells produced water. Because of water invasion, production of gas wells decreased, the liquid carrying capacity of the wellbore becomes poor, even leading to gas well shut-in due to severe accumulation of fluid, hence affecting the normal production of gas wells. The existing drainage gas recovery technology cannot satisfy the actual production. According to the characteristics of gas wells being ultra-deep, mid-high sulfur content, large liquid production, pipe string having packers on it and difficulty in defoaming, etc. The drainage gas recovery technology is presented by perforating tubing and by gas lift using compressor, and the operation procedures is established. This technology need not to modify the production string or to run in gas lifting tools, effectively addressing the problems of equipment anti-sulfur and high temperature-proof, so it is the preferred technology for drainage gas recovery for gas pools. This technology was first tested in Well Longgang 001-18, optimizing the parameters of gas injection pressure, production system, etc. The drainage gas recovery is successful in ultra-deep, high temperature and mid-high sulfur containing gas wells. The successful resumption of gas well production reduces the risk of water invasion in other producing wells within the system. This method can be a reference to drainage gas recovery technology for ultra-deep gas wells in similar gas pools.