TY - JOUR ID - 85258 TI - An Experimental Study of Acid Diversion by Using Gelled Acid Systems Based on Viscoelastic Surfactants: A Case Study on One of Iran Southwest Oilfields JO - Iranian Journal of Oil and Gas Science and Technology JA - IJOGST LA - en SN - 2345-2412 AU - Mehri Ghahfarrokhi, Abdorrahman AU - Kazemzadeh, Ezzatollah AU - Shokrollahzadeh Behbahani, Hassan AU - Safian, Gholam Abbas AD - Technical Expert, Iranian Offshore Oil Company, Tehran, Iran AD - Assistant Professor, Research Institute of Petroleum Industries (RIPI), Tehran, Iran AD - Assistant Professor, Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran AD - Senior Technical Expert, National Iranian South Oil Company, Ahwaz, Iran Y1 - 2019 PY - 2019 VL - 8 IS - 1 SP - 32 EP - 46 KW - Carbonate Acidizing KW - Multi-layered Reservoirs KW - Diverters KW - Gels KW - Viscoelastic Surfactants DO - 10.22050/ijogst.2018.139168.1464 N2 - In matrix acidizing operations, the main goal is increasing permeability. For production engineers, it is desirable that acid could be injected into whole [M.N.1] [amehri.gh2] pay zone. Sometimes, this pay zone has a long height and various sub-layers which have different permeability values. To prevent acid from going completely into the most permeable sub-layer, one of the useful techniques is using diverters, and one of the major groups of diverters is gel diverters. Diverter viscosity changes by temperature and pH, and an increase in viscosity leads to a decrease in its permeability; thus, acid can permeate further through less permeable sub-layers. In this study, two kinds of different viscoelastic surfactants (VES) provided by two different companies were used to produce gel to divert acid into a core plug sample having lower permeability in a dual parallel acid injection set-up. The core plug samples were taken from the pay zone of Ahwaz oilfield, one of Iran southwest oilfields. Before performing the injection test, some viscosity measurement tests were carried out. Unfortunately, one of these two VES’s did not have an acceptable quality and failed to pass the injection tests. However, the other one passed all the tests successfully and diverted the injection fluid. The water permeability values of the low-perm and high-perm core plug samples were 0.91 md and 6.4 md respectively, whereas, after injection, they rose to 1.5 and 18.5 md respectively. UR - https://ijogst.put.ac.ir/article_85258.html L1 - https://ijogst.put.ac.ir/article_85258_65b707d5221b820c15c21f4aff7b3ab8.pdf ER -