The Effect of Various Additives on Matrix Acidizing Effectiveness in Carbonate Reservoirs

Abstract

Matrix acidizing of carbonate reservoirs presents a challenge in the middle east as the horizontal legs become longer some now as long as 30,000 ft with some reservoirs at temperatures above 300 F. In this work we have investigated the diffusivity of acids and alternative acids with various additives vs temperature using a rotating disc apparatus. The pore volume to breakthrough (PVBT) was then measures on various carbonate cores such as Indiana Lime and cores form various Middle East formations. To show the impact of acid and additive selection we have built a horizontal wellbore simulator to predict the impact of lithology, acid type and various additives upon diffusivity and productivity.