A Review of Organic Acids Roles in Acidizing Operations for Carbonate and Sandstone Formations

Abstract

Hydrochloric acid (HCl) is the acid of choice for acidizing operations in most carbonate formations and is the base acid commonly paired with others such as hydrofluoric (HF) in most sandstone applications. However, high dissolving power, high corrosion rate, lack of penetration, and sludging tendency coupled with high temperature can make HCl a poor choice. Alternatively, weaker and less corrosive chemicals such as organic acids can be used instead of HCl to avoid these issues. The objective of this paper is to provide an intensive review on recent advancements, technology, and problems associated with organic acids. The paper focuses on formic, acetic, citric, and lactic acids. This review includes various laboratory evaluation tests and field cases which outline the usage of organic acids for formation damage removal and dissolution. Rotating disk apparatus results were reviewed to determine the kinetics for acid dissolution of different minerals. Additional results were collected from solubility, corrosion, core-flooding, Inductively Coupled Plasma (ICP), X-Ray Diffraction (XRD), and Scanning Electron Microscope Diffraction (SEM) tests. Due to their retardation performance, organic acids have been used along with mineral acids or as a stand-alone solution for high-temperature applications. However, the main drawback of these acids is the solubility of reaction product salts. In terms of conducting dominant wormhole tests and low corrosion rating, organic acids with low concentrations show good results. Organic acids have also been utilized in other applications. For instance, formic acid is used as an intensifier to reduce the corrosion rate due to HCl in high-temperature operations. Acetic and lactic acids can be used to dissolve drilling mud filter cakes. Citric acid is commonly used as an iron sequestering agent. This paper shows organic acid advances, limitations, and applications in oil and gas operations, specifically, in acidizing jobs. The paper differentiates and closes the gap between various organic acid applications along with providing researchers an intensive guide for present and future research.

Study on Stable Loose Sandstone Reservoir and Corresponding Acidizing Technology

“…The experiment of acid dissolution for 2 h was carried out at 45 °C (the formation temperature is 45 °C), and the plugging solution system with large-scale dissolution and a small amount of molten rock was preferred. The slow acid solution system used is the following: 10% solid acid (polycarboxylic acid) [23], 10% HEDP (organic phosphoric acid) [24], and saturated EDTA (amino polycarboxylic acid) [25]. The results show that the solid acid and HEDP can differentially dissolve scale samples and rocks, and the dissolution rates are 97% and ~45%, respectively.…”

“…The results showed that both solid acid and HEDP were retarded acids, relatively weak in acidity. The chelation of the two can dissolve more scale and less sand [23]. It has a better plugging removal effect and less formation destructiveness.…”

Acidificação de matriz em reservatórios de petróleo utilizando ácidos orgânicos: uma revisão

“…Além disso, normalmente não reagem em sua total capacidade ácida devido à liberação de CO2 proveniente da dissolução de carbonatos (CHATELAIN et al, 1976;ALHAMAD et al, 2020); o grau de geração de íons de hidrogênio diminui com o aumento da temperatura e; alto custo se comparado com o HCl (CHANG et al, 2008).…”

Supervised Machine Learning and Multiple Regression Approach to Predict Successfulness of Matrix Acidizing in Hydraulic Fractured Sandstone Formation

“…(Kalfayan, 2008). Other alternative chemical recommendations are a chelating agent, organic acid, and organic acid-HF mixtures (Alhamad et al, 2020), (Shafiq, 2018), (Al-Harbi, 2012), (Mahmoud et al, 2011).…”