凝析致密气藏泄气半径和产能计算研究

发布时间：2018-06-28 20:38

本文选题：致密气藏 + 压敏效应　；参考：《中国石油大学(华东)》2015年硕士论文

【摘要】：致密气藏的产能预测对气藏开发方案设计和气田合理配产都具有十分重要的意义。物模实验表明,致密低渗透气藏存在压敏效应和启动压力梯度等渗流特征,达西定律不再适用,同时,致密凝析气藏还存在着凝析现象。本文主要研究工作包括以下几个方面,首先,利用物模实验推出压敏效应和启动压力梯度的经验公式,并利用边界压力梯度极限法推导了考虑启动压力梯度和压敏效应的气井泄气半径计算公式。其次,利用保角变换的方法,推导了考虑压敏效应和启动压力梯度的气藏压裂直井和压裂水平井稳态产能解析计算公式,为了便于比较压裂效果也推导了未压裂时的产能方程。然后,尝试用一种较为简便的方法进行凝析气藏产能的计算。最后,进行敏感性分析。通过分析,可以看出压敏效应和启动压力的存在会降低气井产量,但是压敏效应对产能的影响更敏感,在高生产压差时尤为明显;对于压裂水平井,水平段长度越长、压裂缝条数越多、裂缝越长,产量越高,但随着这些因素的增加,产量的增幅越来越小,两端密集中间稀疏的裂缝位置分布,有利于产量的提高;地露压差越小,凝析油析出的越迅速,阻碍气的渗流,减低气井产能。
[Abstract]:The productivity prediction of tight gas reservoir is of great significance to the design of gas reservoir development plan and the reasonable distribution of gas field. Physical model experiments show that there are percolation characteristics such as pressure-sensitive effect and starting pressure gradient in dense and low permeability gas reservoirs, Darcy's law is no longer applicable, and condensate phenomenon exists in dense condensate gas reservoirs. The main work of this paper includes the following aspects: firstly, the empirical formulas of pressure sensitivity effect and starting pressure gradient are derived by physical model experiment. The calculation formula of gas well leakage radius considering starting pressure gradient and pressure-sensitive effect is derived by using the boundary pressure gradient limit method. Secondly, using the conformal transformation method, the analytical formulas for calculating the steady-state productivity of gas reservoir fracturing straight wells and fracturing horizontal wells considering the pressure sensitivity effect and the starting pressure gradient are derived. In order to compare the fracturing effect, the productivity equations without fracturing are derived. Then, a simple method is used to calculate the productivity of condensate gas reservoir. Finally, sensitivity analysis is carried out. Through analysis, we can see that the existence of pressure-sensitive effect and start-up pressure will reduce the gas well output, but the pressure-sensitive effect is more sensitive to the productivity, especially when the production pressure difference is high, and the longer the horizontal section length is, the longer the horizontal section length is. With the increase of these factors, the increase of yield becomes smaller and smaller, and the distribution of the cracks between the two ends is dense and sparse, which is beneficial to the increase of yield, and the difference of ground pressure is smaller. The faster the condensate is released, the more obstructed the gas percolation and the lower the gas well productivity.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE328;TE372

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