Petroleum Engineering – Production
Abdorrahman Mehri Ghahfarrokhi; Hassan Shokrollahzadeh Behbahani; Ezzatollah Kazemzadeh; Gholam Abbas Safian
Abstract
Nowadays, use of visco-elastic surfactants as the main component of gel diverters is becoming more and more common among well completion engineers, as well as stimulation service companies. Gel diverter, as other kinds of diverters, is used in multi-layered carbonated reservoirs to diver acid into less ...
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Nowadays, use of visco-elastic surfactants as the main component of gel diverters is becoming more and more common among well completion engineers, as well as stimulation service companies. Gel diverter, as other kinds of diverters, is used in multi-layered carbonated reservoirs to diver acid into less permeable sublayer. As use of these materials becomes more common, modeling and simulating the gel-acid injection process becomes more required. In this study, a mathematical model is generated to simulate gel-acid injection process, and experimental data is compared with data predicted by the model. The purpose of this study is to investigate the field possibility of injection gel-acid and to generate a model for simulating this process, in order to smart permeability enhancement in Ahwaz oilfield, one of Iranian Southwest oilfields. The solutions predicted by model are in an acceptable correlation with experimental data. The generated model can be used for other multi-layered carbonated oilfields.
Petroleum Engineering – Production
Abdorrahman Mehri Ghahfarrokhi; Ezzatollah Kazemzadeh; Hassan Shokrollahzadeh Behbahani; Gholam Abbas Safian
Abstract
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. ...
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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.