Papers by Keyword: H₂S/CO₂

Abstract: The four-point bending method and weight loss method were used to study respectively the stress corrosion cracking behavior and weightlessness corrosion situation of the baosteel BG80S steel in the simulated field environments. The experimental results shown that BG80S won't occur to stress corrosion cracking when the maximum loading stress is 85% Rt0.5 ; the corrosion rates increase with the rising of temperature which is from 40°C to 80°C under the dynamic and static conditions of the simulated environments; the dynamic corrosion rates are between 1.5558 and 1.7523mm/a and the corrosion rates are 0.4827～1.4078mm/a under the static conditions, both of which belong to a serious corrosion category; the form of corrosion is uniform corrosion under the dynamic conditions; because the corrosion products exist micro defects under the static conditions of 80°C, the experimental samples have had the localized corrosion.

Abstract: The anti-corrosion performance of Tiangang TP95S casing steel was studied by high temperature autoclaves simulating the high-temperature and high-pressure H₂S/CO₂ environment. The experimental results show that the corrosion rates increase with the rising of temperature which is from 40°C to 80°C under the dynamic and static conditions of the simulated environments; the dynamic corrosion rates are between 1.7294 and 1.8601mm/a and the corrosion rates are 0.4264～1.2715mm/a under the static conditions, both of which belong to a serious corrosion category; the dynamic corrosion samples have had the localized corrosion at 40°C, but the local corrosion of the static corrosion specimens appeared at 80°C; the corrosion product of TP95S steel takes FeS as the core in the case of static corrosion at 40°C.

Abstract: Usually, marine carbonate gas reservoirs contain formation water with high content of CO₂&H₂S, It is difficult to satisfy the requirement of cementing quality in the gas reseroirs exploration due to the corrosion effect of formation water on cement. In this thesis, corroding tests of cement in formation water, which derived from a development well in northeast Sichuan province, were based on the simulation environment condition of 90°C under 0.1 MPa, 5 MPa and 10Mpa. Performances of cement including mineral composition, microstructure and permeability before and after corrosion were measured by TG-DTA, SEM, XRD and gas permeability and porosity of dense rock core tester. The results show that main corrosion products of cement being corroded in formation water with high content of CO₂&H₂S are ettringite, CaCO₃ and CaSO₄, both strength reduction and gradual rising of permeability can occur as testing pressure increasing. Accordingly, the corrosion mechanism and the damage process of cement under formation water with high content of CO₂&H₂S are expounded in the end.

Abstract: The corrosion behavior of Fe₃Al was studied by high temperature autoclaves in H₂S/CO₂ environment. By Stereo Microscope, we found that the corrosion film of Fe₃Al is thin and crack at 60°C, 4.0 Mpa,after 72h in autoclaves; Phase analysis by XRD showed that the main composition of corroded products is FeS; its corrosion are Ⅲ corrosion resistant type and corrosion rating of 4, mainly pitting, and average corrosion rate of 0.2106 mm/a.

Abstract: Today’s global exploration of oil and gas leads to a range of highly corrosive environment that, in turn, require corrosion resistant high nickel content alloys for Oil Country Tubular Goods. Aimed at the problem of oil tube corrosion in environment with high content of H2S and CO2, the corrosion behavior of two nickel based alloys in 15%NaCl solution containing H2S/CO2 in high temperature and high pressure environments were researched. The pitting corrosion behavior of Ni-based alloys were investigated in FeCl3 solution by polarization curve and immersion test. The scanning electron microscopy(SEM), energy disperse spectroscopy(EDS) were applied to analyse the microstructure and corrosion performance of the samples. The results showed that the pitting-resistant of G3 was superior to Incoloy825.With the experimental temperature increasing, the corrosion rates increased and some slight corrosion pits appeared on the surface of Incoloy 825, Its maximum corrosion rate was 0.018mm/a. XRD showed that the corrosion films formed on nickel base alloys were consist of NiS, FeS and the oxides of Ni and Cr. The polarization curves showed that there were different corrosion behavior of two alloys, the anodic curve of G3 has an obvious passivation region, and there has higher pitting potential .