Selective matrix acidizing of horizontal wells Academic Article uri icon


  • The PI of a horizontal well in an anisotropic medium is calculated during a process of partial acidization, in which damage removal occurs over only a fraction of the well length. Two numerical simulators are used in this work: an acidizing simulator, which calculates the permeability distribution around the wellbore; and a reservoir simulator, which calculates the PI of the well. By applying mathematical transformations, it is possible to reduce the acidizing model from a 2D to a 1D problem. By comparing treatment results, it is possible to select the optimal volume of acid, injection rate, and fraction of the length to be acidized for each well. The same procedure also may be applied for vertical wells both with and without anisotropy. Simulation results indicate that the application of a partial acidizing strategy reduces the total amount of acid required for significant improvement in well productivity, substantially reducing the financial, operational, and environmental risks involved in the treatment of a horizontal well. In most cases, the optimal injection rate for sandstone acidizing is the maximum rate that does not fracture the formation. Copyright 1995 Society of Petroleum Engineers.

published proceedings

  • SPE Reprint Series

author list (cited authors)

  • Da Motta, E. P., Hill, A. D., & Sepehrnoori, K.

complete list of authors

  • Da Motta, EP||Hill, AD||Sepehrnoori, K

publication date

  • December 1998