关键词: 水平气井, 均匀酸化, 表皮因子, 均匀, 残酸返排

Abstract:

Horizontal well staged acidizing with packer has been an important stimulation treatment to achieve uniform acidizing
in anisotropic reservoir，so the study of skin factor after staged acidizing is of great importance. Based on the elliptic
damage zone near the horizontal gas well，the authors take by into consideration the uniform treatment by acids and influence
of residual acid back flow on gas flow in the reservoir，and dividing the flow problem of composition area in elliptic damage
zone into three flow problems in homogeneous region，taking advantage of resistance superposition theory，we eventually get a
new method to calculate the skin factor of horizontal gas well after staged acidizing. The case study shows the local skin factor
of horizontal gas well after staged acidizing becomes smaller from the heel to toe-end along the direction of wellbore；it also
decreases with the increase of acidifying radius and permeability of acidizing zone，but increases with the increase of maximum
immersion radius. The study in this paper will offer an new approach to the calculation of the skin factor of horizontal gas well
after acidizing.

Key words: horizontal gas-well, staged acidizing, skin factor, uniform, residual acid back flow