An Analytical Derivation Method to Estimate Pore Volumes to Breakthrough in Carbonate Acidizing with Complex Acids

Abstract

Acidizing stimulation is a common and useful method within the oil well treatment to create wormholes channels in carbonate formations to increase the reservoir oil and gas production. Finding the amount of pore volumes to breakthrough number is a critical target in carbonate acidizing. Finding this number by experimental works needs a substantial amount of energy, price and time. For that reason, this study expected to determine an analytical technique to estimate the pore volumes to breakthrough number with high accuracy. This method is accomplished by exclusively applying formation and acid properties without using any experimental works. Pore volumes to breakthrough calculation are done through developing an analytical method based on the conservation of mass law in which the carbonate core is considered as a closed system and the overall mass in the system as a constant throughout the process of acid. Moreover, a constant number is added to the mathematical part of the model with the aim of removing the dimensionless Damköhler number which is supposed to be calculated experimentally. This method results are compared to four other experimental works, which led to calculating the average accuracy of this model that is shown to be 81.36%. This study puts forward an inclusive analytical method to estimate the number of pore volumes to breakthrough with an acceptable accuracy rate just through known core and acid and properties.