Corrosion-resistant systems of formate packer fluid for G3/N80/TP110SS pipes at high temperature, high pressure and high H ₂ S/CO ₂ ratios

Abstract

A series of corrosion problems caused by high-temperature, high-pressure and high-acid gas environments has been an issue in oil and gas production for a long time. During the development of a high-acid gas field, the petroleum pipe is subjected to many aspects of corrosion, and the corrosion mechanism is complicated by the condition of the coexistence of H2S/CO2. Based on the study of the corrosion problem associated with the formate packer fluid in Southwest China, three kinds of steels were studied for corrosion prevention in the alloy G3/N80 steel/TP110SS steel. The study shows that the corrosion rate of the formate packer fluid is low, but corrosion is severe in environments characterized by high temperatures, high pressures and high-acid gas contents. Based on the consideration of cost and the difficulty of realization, an anti-corrosion system was constructed based on the existing packer fluid, mainly through the introduction of a variety of anti-corrosion additives. Through the selection of various additives and corrosion experiments, a corrosion protection system of formate packer fluid was developed. Corrosion tests show that the corrosion rate of the system must be less than 0.076 mm yr−1 to achieve the purpose of corrosion protection. The formate packer fluid with corrosion protection can meet the needs of the current application.

A comparative study of brine solutions as completion fluids for oil and gas fields

“…Corrosion tests are essential to evaluate the potential impact of completion fluids on well construction materials, such as L80 steel. The primary quality of a completion fluid is its non-corrosive nature, as brines, commonly used as base fluids, can induce corrosion, posing risks to wellbore pipes and equipment 24 , 29 – 32 . The corrosion testing procedures delineated in this section are conducted in strict adherence to the comprehensive guidelines specified in API RP13 standards.…”

“…In laboratory settings, formate fluids exhibited minimal corrosion. However, under conditions of high temperature and pressure, in the presence of CO 2 and H 2 S gases, the corrosion caused by formate fluids significantly increased; so they designed a corrosion system with anti corrosion additives that overcomes this problem; but they didn’t investigate the effect this system has on formation damage and ignored other types of fluids 24 . In 2020, Tariq et al, introduced a completion fluid additive known as polyoxyethylene quaternary ammonium gemini surfactant, which effectively prevents clay swelling.…”

Carbon steel corrosion controlled by vegetable polyol phosphate, in medium containing chloride and glyoxal: influence of phosphate content and CO2

“…The nature of the corrosion caused by CO 2 varies according to specific environmental conditions, with temperature and pressure of CO 2 standing out in this corrosion process [7]. With regard to deep waters, like, for instance, the pre-salt oil exploration in Brazil [8], in addition to the high concentrations of the gases CO 2 and H 2 S [9], the presence of chloride in both water injection and packer fluid constitute a more critical situation to corrosion [10,11]. Hydrogen sulfide has been mitigated by chemical agents, which convert it into inert or less toxic products.…”