摘要
针对存在纵向层间压差的致密气藏,建立了地质模型和物理模型,模拟致密气藏多层合采的衰竭开采过程,进行层间干扰、气层供气特征、产能变化规律等研究。模拟结果显示,渗透率差异不大的高、低压气层进行合采时,不同压力气层具有明显的层间干扰,高压气层天然气通过井筒向低压气层倒灌。高、低压气层的最终采收率不受初期配产和初始压差影响。生产初期,高压气层瞬时产气量较高,大于初期配产,低压气层瞬时产气量为负值,随后高压气层瞬时产气量减小,低压气层瞬时产气量增大,最后两者趋于一致。生产末期总产气量贡献率受初始压差和初期配产影响较小,高压气层贡献率大于低压气层。模拟证实,多层合采比单层开采具有更强的稳产能力,产量高,满足合采条件时尽可能进行合采。但开发中需将纵向层间初始压差控制在一定范围内,减小层间干扰。
For the tight gas reservoir with interlayer pressure differential vertically, we built a geological model and a physi- cal model to simulate the depletion process of tight gas reservoir, and probed into the interlayer interference, gas supply characteristics, and productivity variation. Simulation results revealed that interlayer interference was obvious in the gas layers of different pressure, and the natural gas flowed from high-pressure gas layers to low-pressure ones through well bore, when conducting commingling production in high and low pressure gas layers with low permeability contrast. The ulti- mate recovery of high and low pressure gas layers was not influenced by initial production allocation and initial pressure difference. At initial stage of production, instantaneous gas production was higher and bigger than initial production alloca- tion in high pressure layers, while that of low pressure layers was negative. After then, the instantaneous gas production of high pressure layers declined, and that of low pressure ones increased. Finally, both showed no difference. At the end of production, contribution rate of total gas production was less affected by initial pressure differential and initial production allocation, and the contribution rate of high pressure gas layers was higher than low pressure ones. Simulation proved that the productivity was more stable and higher by means of muhilayer production as compared with single-layer production. Therefore, muhilayer production should be more employed if feasible. Nevertheless, the vertical interlayer initial pressure differential had to be controlled within limits during development, so as to reduce interlayer interference.
出处
《非常规油气》
2016年第2期59-64,共6页
Unconventional Oil & Gas
基金
致密气藏渗流机理研究项目(2012-8070)资助
关键词
致密气藏
层间压差
配产
层间干扰
多层合采
tight gas reservoir
interlayer pressure differential
production allocation
interlayer interference
muhilayer production
