Experimental Investigation for the Effect of the Core Length on the Optimum Acid Flux in Carbonate Acidizing

Abstract

Matrix acidizing is commonly used to stimulate wells in carbonate reservoirs. Large amounts of lab tests indicate an optimum acid interstitial velocity (Vi-opt, injection rate over flow area and porosity) exists, which results in the minimum volume of acid required for wormhole propagation and best stimulation results. Previous tests showed that the Vi-opt increased with increasing core length, but it is not clear if the Vi-opt can be independent of the core length when the core length reaches a certain value. In this work, a series of core flood experiments with different core lengths was carried out to determine the Vi-opt. Results showed that the Vi-opt became a constant when the core length reached a certain length. The finding of this study can guide lab researchers to use proper core lengths when determining the Vi-opt.