天然裂缝对气井产能影响研究

摘要

Based on time invariant seepage theory, adopting equivalent filtrational resistance method, a theoretical model of time in⁃variant seepage was established for fractured gas reservoir. Considering natural fracture, gas well production increased range expres⁃sion was derived, and the effects of natural fracture percolation parameters were analyzed. The results show that the more the frac⁃ture close to wellbore, the greater the fracture length will have and the more the gas well productivity will increase. Both fracture ap⁃erture and fracture permeability are existed in right scope, namely the exists optimum fracture conductivity. Only when fracture con⁃ductivity is low, can fracture density have effects on gas well productivity. The results theoretically prove that for fractured low per⁃meability gas reservoir, the gas well productivity can increase dramatically in well spacing of natural fracture development zone.%基于稳态渗流理论，采用等值渗流阻力法，建立了裂缝性气藏稳态渗流理论模型，推导了考虑天然裂缝时气井产量提高幅度的表达式，分析了天然裂缝渗流参数对气井产能的影响。研究结果表明：裂缝越靠近井筒，裂缝长度越大，气井产能提高越明显；裂缝开度和裂缝渗透率均存在合适的范围，即存在最佳裂缝导流能力；裂缝密度对气井产能的影响仅在裂缝导流能力较小的情况下才会表现出来。从理论上证明了对于裂缝性低渗透气藏，选择在天然裂缝发育区布井能够较大幅度提高气井产能。