| 摘要 |
A Nitrogen Assisted Depletion Drive (NADD) for enhancing natural gas recovery from a partially depleted natural gas containing formation (20,30) in which natural gas is trapped in pore water below a Free Water Level (25, FWL, IGWC), comprises injecting non-corrosive Nitrogen (N2) containing drive gas via at least one injection well (22, 31A-D) into the pore water below the Free Water Level (FWL or IGWC) in the formation (20,30), thereby releasing the trapped natural gas from the pore water and lifting the released natural gas to above the Free Water Level (25, FWL, IGWC) and enhancing natural gas production whilst inhibiting subsidence of the overburden. |
