New Insights into Wormhole Propagation in Carbonate Rocks Using Regular, Gelled and In-Situ Gelled Acids (2010)

New Insights into Wormhole Propagation in Carbonate Rocks Using Regular, Gelled and In-situ Gelled Acids A. M. Gomaa; A. M. Gomaa Texas A&M University Search for other works by this author on: This Site Google Scholar H. A. Nasr-El-Din H. A. Nasr-El-Din Texas A&M University Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Production and Operations Conference and Exhibition, Tunis, Tunisia, June 2010. Paper Number: SPE-133303-MS https://doi.org/10.2118/133303-MS Published: June 08 2010 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Gomaa, A. M., and H. A. Nasr-El-Din. "New Insights into Wormhole Propagation in Carbonate Rocks Using Regular, Gelled and In-situ Gelled Acids." Paper presented at the SPE Production and Operations Conference and Exhibition, Tunis, Tunisia, June 2010. doi: https://doi.org/10.2118/133303-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE International Production and Operations Conference and Exhibition Search Advanced Search Abstract It is well known that the efficiency of regular acid treatments goes through a maximum at an optimum acid injection rate where it gives the maximum wormhole propagation rate (ratio between wormhole length to pore volume of acid required to breakthrough). This rate is a strong function of the acid-rock reaction: diffusion of the acid to the rock, surface reaction, and mass-transport of the reaction products. Adding a polymer and other additives to the acid may affect the wormhole propagation rate. However, literature survey didn't highlighted in details how the wormhole propagation rate will change when polymer and crosslinker will be existing with the regular acid. Therefore, the objective of this study is to determine the wormhole propagation rate of gelled and in-situ gelled acids as a function of the injection rate. The effects of temperature, lithology, and initial permeability on the wormhole propagation rate were considered in this work.A coreflood study was conducted using calcite cores at temperature range 100 to 250 °F. Injection rate was varied from 1 to 20 cm3/min using 5 wt% HCl regular, polymer gelled, and in-situ gelled acids. Calcium, cross-linker, and acid concentrations were measured for the core effluent samples.The wormhole propagation rate of gelled acid required was higher than regular acid where gelled acid required less acid volume to breakthrough. However, the wormhole propagation rate of in-situ gelled acid required was lower than regular acid where in-situ gelled acid required a higher pore volume to breakthrough. Three regions were obtained for the wormhole propagation rate of in-situ gelled acid as a function of the injection rate: Region I, where acid injection rate is low, and in-situ gelled acid wasn't able to breakthrough from the cores at injection rate less than 5 cm3/min. Region II, where the acid volume required to breakthrough decreased as injection rate increased in the range between 5 and 10 cm3/min. Region III, where the acid volume injected increased with the injection rate at injection rate higher than 10 cm3/min. The optimum injection rate wasn't affected by temperature, or initial core permeability. The volume required to breakthrough decreased as the temperature was increased, and as the initial core permeability increased. Keywords: acid, initial core permeability, upstream oil & gas, acid injection rate, carbonate reservoir, injection rate, regular acid, drilling fluid chemistry, in-situ gelled acid, complex reservoir Subjects: Drilling Fluids and Materials, Reservoir Fluid Dynamics, Unconventional and Complex Reservoirs, Drilling fluid selection and formulation (chemistry, properties), Acidizing, Flow in porous media, Carbonate reservoirs, Well Operations, Optimization and Stimulation Copyright 2010, Society of Petroleum Engineers You can access this article if you purchase or spend a download.