Abstract: Stress sensitivity is one of the factors influencing fracture net deliverability of multistage fractured horizontal well for tight sandstone gas reservoirs. Based on seepage characteristic of tight sandstone gas reservoir, seepage law after fracturing work and steady seepage theory, flowing resistance method was used to derive fracture net deliverability correlation considering stress sensitivity of multistage fractured horizontal well for tight sandstone gas reservoirs, and then the correlation was used to analyze fracture parameters and stress sensitivity level on gas production rate. The results indicate that with increasing fracture flow conductivity and fracture net permeability, gas production is gradually increased, but the increase is slowed down. The unimpeded flow increases gradually with the increase of fracture half length, and increases rapidly with the increase of fracture conductivity. Therefore, in order to improve gas reservoir productivity, it is more significant to improve fracture halflength than fracture flow conductivity. The greater the stress sensitivity coefficient is, the greater the permeability decreases with the production, and the more the productivity of the gas well decreases.

Key words: Tight sandstone gas reservoirs, Stress sensitivity, Fractures horizontal well, Fracture net, Productivity

摘要： 应力敏感是影响致密砂岩气藏多级压裂水平井缝网产能的重要因素之一。针对致密砂岩气藏渗流特征,根据气井压裂后气体渗流规律的变化,基于稳定渗流理论,利用渗流阻力法建立了考虑应力敏感的致密砂岩气藏多级压裂水平井缝网产能公式,并利用该公式分析了裂缝参数及应力敏感对气井产量的影响。研究表明,随着裂缝导流能力或缝网渗透率的增大,产气量逐渐增加,但是增加幅度减缓;气井无阻流量随着裂缝半长的增大逐渐增加,同时随裂缝导流能力增大先快速提高后趋于平缓,因此,致密砂岩气藏中增加裂缝半长比增加裂缝导流能力更为重要;应力敏感系数越大,随着生产进行,渗透率降低幅度越大,气井产能降低越多。

关键词: 致密砂岩气藏, 应力敏感, 压裂水平井, 缝网, 产能