Projects / Programmes source: ARIS

Green Corrosion Inhibitor Formulation Design for Well Acidizing Procedures in Drilling Applications

Research activity

Code Science Field Subfield
1.04.00  Natural sciences and mathematics  Chemistry   

Code Science Field
P400  Natural sciences and mathematics  Physical chemistry 

Code Science Field
1.04  Natural Sciences  Chemical sciences 
steel, corrosion, corrosion inhibition, acid, well, exploration of natural resources, oil, gas
Evaluation (rules)
source: COBISS
Researchers (1)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  28477  PhD Matjaž Finšgar  Chemistry  Head  2014 - 2016  385 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0794  University of Maribor, Faculty of Chemistry and Chemical Engineering  Maribor  5089638012  12,736 
The main idea of the proposed postdoctoral project is the development of environmentally acceptable corrosion inhibitor formulations (CIFs) to protect steel materials against acid corrosion in oil and gas wells during the acidizing procedure and to explore their mechanisms. These CIFs are to be developed for drilling applications in the North Sea, where the environmental legislation is one of the strictest (which is why term green CIF is used). CIFs will be developed to inhibit steel corrosion in methanesulphonic acid (MSA) and HCl solutions. The majority of well acidizing procedures carried out in the oil and gas industry utilize HCl due to the low cost and we cannot expect that use of this acid will be eliminated in the near future. Therefore, we can only provide better HCl technologies than currently available. On the other hand, no information on using MSA solution in drilling applications has been published in the literature. The emphasis of this project will be on studying the corrosion of the 4 steel materials most frequently used for well construction, in acid solutions at elevated temperatures. Why do we want to investigate and understand the limitations of MSA, in addition to the better-known HCl, in drilling applications? It is believed that MSA will enhance the operational safety of the personnel involved in the acidizing procedure. For example, one advantage of MSA over HCl is that it has very low vapour pressure and a high boiling point, thus it is odour-free and evolves no dangerous volatiles. From the environmental perspective, MSA is usually described as a “green acid” [Gernon et al., Green Chem., 1 (1999) 127]. A very important step in the oil and gas industry is the well acidizing procedure, which is a rock reservoir (the origin of the natural resource) stimulation technique used to improve productivity. During the acidizing procedure, steel pipelines are in contact with an acid solution, which can lead to severe corrosion. The corrosion of pipelines in the oil and gas industry represents a large part of the total cost and source of potential danger to the personnel involved. Thus, the selection of an inhibited acid solution (against corrosion) is crucial. A corrosion inhibitor is a chemical compound (frequently organic) that is added to the corrosive medium. The corrosion inhibitor adsorbs on the metal surface, which is in contact with the corrosive medium, and by means of a certain mechanism decreases the metal’s corrosion rate. Organic compounds, by themselves, when used as corrosion inhibitors in drilling applications, are usually not effective enough for corrosion control and a proper mixture containing additional intensifiers, surfactants, solvents, and co-solvents is needed. This mixture is called a corrosion inhibitor formulation – CIF. Most of the CIFs developed for conventional acids no longer meet the Oslo Paris Commission (OSPARCOM, Fourth North Sea Minister’s Conference – Esbjerg, Norway, 8-9 June 1995) requirements, because their ingredients may be harmful if discharged into the environment. OSPRAMCOM has the ultimate goal of replacing all environmentally hazardous chemical discharges by 2020. This represents a significant problem for the existing CIFs mainly used for HCl and will force the industry to replace or reformulate them. The goal of many research studies is to present reliable corrosion data to drilling companies in order to test CIF acceptability under large-scale operation in real field trials. It has to be emphasized that drilling companies are very interested in using safer and more environmentally acceptable alternatives than those currently employed, especially to meet the OSPARCOM requirements. Drilling companies commonly request solutions for operations at 150 degrees Celsius, with corrosion rates slower than 0.243 kg/(m2 test period) (0.05 lb/(ft2 test period)), and the pitting index should not be higher than 3.
Significance for science
Some data in the literature on environmentally friendly corrosion inhibitors for HCl exist, however it mainly concerns research carried out at room temperature. On one hand, the literature on corrosion inhibition processes in acidic conditions at elevated temperatures is scarce, especially regarding corrosion inhibitor formulation design found to be effective in preventing oilfield pipeline corrosion. Even rarer in the literature (if existing at all) is information on corrosion inhibitor formulations effective at elevated temperatures. Hitherto, no research work on the use of MSA and its corrosion inhibitors or formulations in drilling applications has been published. Therefore, this is the first attempt at using MSA in this field as found in this project. Moreover, in this project it was proposed that uninhibited MSA could be utilized in acidizing procedures in petroleum wells constructed of 22Cr steel. MSA was suggested as a substitute for conventional acids such as HCl which require the use of corrosion inhibitors. Furthermore, for the first time a systematic electrochemical study was presented regarding the corrosion inhibitor formulation design with the addition of certain key components in the final formulation, and their effect on the corrosion of steel. This first attempt of using MSA in oilfield applications, including the proposed inhibitors action mechanisms, as well as their inhibition efficiency were published in scientific journals and presented at international conferences. In this project a combined electrochemical and surface analytical approach was utilized which provided the qualitative and quantitative information necessary for a detailed understanding of corrosion inhibition mechanisms at elevated temperatures. In such study, especially important was the use of AFM technique, which clearly showed the differences in nanoscale and these phenomena were successfully implemented into real field corrosion trials, which are significantly more robust. Fundamental research directed at an improved understanding of corrosion processes is important for general scientific progress in the corrosion inhibition field. The importance of this research is even more pronounced because only environmentally friendly chemicals for corrosion inhibitor formulation design were used. This project results were presented in 14 scientific articles. Among them is the most important work [FINŠGAR, Matjaž, JACKSON, Jennifer, Application of corrosion inhibitors for steels in acidic media for the oil and gas industry: a review, Corrosion science, 2014, vol. 86, pp. 17-41], which is since 2014 the most downloaded and the most cited article in the scientific journal Corrosion Science. As reported by scopus.com it reached until now 97 citations and according to mendeley.com it has more than 45 000 views. This research was also presented in 3 invited lectures among which one was a plenary lecture.
Significance for the country
The successful use of MSA in drilling applications within this postdoctoral project is novel and its successful implementation contributes to the reputation of the Faculty of Chemistry and Chemical Engineering of the University of Maribor. In addition the contribution is extended to other research institutions and individuals that the postdoctoral candidate has already and will co-operate with in the future, i.e. the personnel employed at the Faculties of Chemistry and Chemical Technology of the Universities of Maribor and Ljubljana, the Faculty of Mechanical Engineering (Maribor), Jožef Stefan Institute, the Slovenian National Building and Civil Engineering Institute, the National Institute of Chemistry, and BASF SE (Ludwigshafen, Germany). Moreover, this also contributes to the broader recognition of Slovenia in the scientific community, which is shown by new plenary lecture invitations at the conference and broader visibility of our scientific work. This fundamental research will enable new cooperation with other research institutions as well as with Slovenian and foreign industry. The developed technology is useful also for other industrial fields in Slovenia and in the world, where steel and also other materials e.g. aluminium- and copper-based) need to be protected against corrosion (by using corrosion inhibitors (especially where non-toxic green inhibitors are needed), to protect the equipment and the personnel involved preventing this way possible injuries. Within this project, a successful cooperation with the largest chemical company in the world – BASF SE, on this topic, and also in other fields was carried out. Based on that, I was entrusted with 2 new international industrial projects. A combined scientific-industrial cooperation contributes to knowledge exchange, which was transferred to younger generations of students and other scientists.
Most important scientific results Annual report 2014, 2015, final report
Most important socioeconomically and culturally relevant results Annual report 2014, 2015, final report
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