Failure analysis of local settlement induced Q345R bottom plate cracking of crude oil storage tank
Zhang Shuxin,
Kang Chun,
Zhang Penggang,
Luo Jinheng,
Shao Yingjie,
Wu Gang,
Deng Banghui
Affiliations
Zhang Shuxin
Tubular Goods Research Institute, China National Petroleum Corporation & State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an, Shaanxi 710065, China; School of Civil Aviation, Northwestern Polytechnical University, Xi'an 710072, China; Corresponding author.
Kang Chun
Tarim Oilfield Company, PetroChina Company Limited, Korla 841000, China
Zhang Penggang
Tarim Oilfield Company, PetroChina Company Limited, Korla 841000, China
Luo Jinheng
Tubular Goods Research Institute, China National Petroleum Corporation & State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an, Shaanxi 710065, China
Shao Yingjie
Xi’an Petroleum University, Xi’an, Shaanxi 710065, China
Wu Gang
Tubular Goods Research Institute, China National Petroleum Corporation & State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an, Shaanxi 710065, China
Deng Banghui
Tarim Oilfield Company, PetroChina Company Limited, Korla 841000, China
A 5000m3 single deck floating roof crude oil storage tank was found to have a cracked Q345R bottom plate during an open tank inspection. To analyze the cause of the failure, a series of experiments were carried out. The results showed that the chemical composition of the failed crude oil storage tank bottom plate material Q345R had a slight excess of S, V, and Ti which causes the material to form a bainite structure, resulting in a hard and brittle material with poor toughness. Q345R is susceptive to H2S stress corrosion cracking according to SCC test. Based on the working condition investigation, the cracked plate was subjected to the local settlement and H2S contained corrosive medium. With the stress concentration induced by local settlement, the bottom plate cracked. In order to avoid such incidents, Q345R material should be avoided in H2S containing environment, and online monitoring should be carried out regularly to assess the overall condition of the tanks.
