Improving the Efficiency of Matrix Acidizing With a Succinoglycan Viscosifier

TLDR

Matrix acidizing efficiency is increasingly critical as more long horizontal wells are drilled, yet selective placement is difficult and hardware solutions are costly, making succinoglycan biopolymer gelled acids a promising alternative. The study proposes using viscosified acids as a potential solution to improve matrix acidizing. The authors characterized the temperature‑ and time‑dependent rheology of succinoglycan in HCl, fitted the data to a model, and used it in an optimization example. Placement of gelled acids over the treatment interval greatly improves acidizing uniformity.

Abstract

Summary The efficiency of matrix acidizing treatments is becoming more critical, especially as more wells are drilled with long, horizontal sections. Without some sort of selective placement or diversion technique, zones near the point of acid injection or with high injectivity will be preferentially treated. Yet hardware solutions are often prohibitively expensive, and many available diversion techniques are not readily applied in openhole horizontal sections. In this context, viscosified acids offer a potential solution. An investigation into the placement of gelled acids over a treatment interval has shown that they can greatly improve the uniformity of acidizing. Other studies have revealed that a succinoglycan biopolymer in hydrochloric acid (HCl) exhibits nearly ideal gelled-acid properties over a certain temperature range. To design a gelled HCl treatment, the temperature- and time-dependent rheology of succinoglycan in HCl has been determined. The experimental data have been fit to a model that is used here in an example optimization procedure.