Research on Construction and Operation Parameters of an Underground Oil Storage in Depleted Salt Caverns in the East of China

2021 ◽  
Author(s):  
Fu Jin ◽  
Wang Xi ◽  
Ding Mingming ◽  
Yang Guobin ◽  
Zhang Shunyuan ◽  
...  

Abstract The crude oil price has been keeping at a low level in recent years, which made China's government put more efforts in the development of underground oil storages in depleted salt caverns. Under the initiative of "the Belt and Road", a more concrete concept which is "the Silk Road Economic Belt and the 21st-Century Maritime Silk Road" successfully connects Jiangsu Province in the east of China. Consisting of 20 depleted caverns, Huai'an project that is still under planning is one of the most successful examples that turn depleted salt caverns into underground crude oil storages in China. Each cavern takes up 24×104m3, while the project totally takes up 480×104m3. TDMA algorithm was adopted to solve the heat exchange model of oil, brine and surrounding rocks, revealing the relationship between temperature and cavern pressure. Salt rock safety factor, salt cavern shrinkage ratio, axial stress and ground subsidence were taken into consideration to establish a 3-dimension salt rock creep model for 19 depleted salt caverns, so that the caverns’ shapes were optimized. Hydrodynamics models were used to determine the oil's flow rate into and out of a 1000m deep cavern whose thermal field was simulated by software to reveal the temperature limit of oil and brine. Due to geothermal gradient and continuous heat transmission, the average temperature of oil and brine goes up from 35°C to 44.3°C within 7 years, while the inner pressure goes up from 12.96MPa to 21.93MPa in a depleted salt cavern. Salt creep ratio decreases as oil is stored in underground caverns for a longer period. Salt is hardly penetrated by oil, while the temperature change has a strong influence on caverns’ internal pressure. The thermal expansion factor and compressibility coefficient of crude oil and brine are both crucial to the temperature's effect on internal pressure. Caverns that have larger segments in their upper-middle or middle parts are more stable and resistant to salt creep than those that have larger segments in their lower parts. When oil is injected or pumped out, it is necessary to make the internal pressure lower than the static pressure of surrounding rocks. Hence, the most appropriate flow rate of crude oil is 4.5m/s. Crude oil that is stored in deep salt caverns may be heated up to 60°C due to the geothermal gradient, but the flammable gas in oil is rapidly gasified or even explodes when it is pumped out to the surface. To avoid accidents and air pollution, oil is cooled down before being delivered via pipelines. Oil tanks used to be applied by scale in China, however they are too obvious on the ground to comply with national strategic energy safety. Compared with oil tanks of similar volumes, the Huai'an underground oil storages may save the overall cost by 35.3%. It is the first time that the salt rock creep model is established in depleted salt caverns, while the conclusion overthrew the common preference of regular cylindrical caverns.

2013 ◽  
Vol 353-356 ◽  
pp. 1345-1352
Author(s):  
Ming Zhang ◽  
Qiang Yang

Salt cavern storage is usually in bedded salt rock formation except salt dome, in particular in China. The rocks composing a bedded salt rock formation, e.g., mudstone, rock salt, interlayer, etc., often present viscoelastic-plastic behaviors, which is an important influencing factor of the long-term stability of salt caverns in it. Modelling the rheological behavior with the Druck-Prager creep model, an example of stability analysis of four salt caverns at Jintan Salt Mine of China with the finite element method is elaborated in this paper. The results show that besides the inevitable loss of effective storage room with time due to creep deformation, which decreases evidently with internal pressure but decreases slowly at a certain pressure value, the variation of operating internal pressure in each cavern can cause the change of volumes of other nearby caverns and then affect the stability of all the caverns. The internal pressure difference should be as small as possible during the operation of salt caverns.


2013 ◽  
Vol 577-578 ◽  
pp. 561-564
Author(s):  
Ji Wei Ma ◽  
Zhi Yin Wang ◽  
Jin Peng Wu

According to salt rock creep test data and strain variation regulation of a salt mine, salt rock creep parameters are obtained based on Burgers creep model fitting. Statistical study of the probability distribution of the salt rock Burgers model creep parameters is carried out by K-S, A-D and C-M test method, from which probability model for each creep parameters is obtained. To achieve the purpose of determining the optimal probability model for each creep parameters, considering the acceptable level of various test method to different hypothesis probability model, the author put forward the comprehensive optimal acceptance criteria on the basis of limited comparison method, the correctness of which is proved by test result.


Author(s):  
Jack Broyles ◽  
Paul Dusseault ◽  
Frank Vanden Elsen

In response to industry demand, Hardisty Caverns Limited Partnership (HCLP) has developed cost effective underground storage facilities with a capacity to store 480,000 m3 (3 million barrels) of crude oil. This project is unique through the integration of existing underground salt caverns into a significant North American crude oil transportation hub. Annually, 64 million cubic meters (400 million barrels) of oil move through this hub. This project utilizes existing caverns developed in the late 1960’s. Significant work was required to upgrade the cavern facilities and to construct new surface facilities to integrate the caverns into the crude oil transportation hub. Remote operation of the facility is performed from a control centre in Edmonton. In this paper, the key features of the design and construction of the Hardisty Cavern Storage Project will be presented. Of particular interest are the unique challenges presented due to hydraulic considerations related to cavern operation with multiple product characteristics and to provide crude oil movements exchanges between the cavern storage facilities and both low flow rate feeder pipelines and high flow rate transportation pipelines.


Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4325
Author(s):  
Zhihua Wang ◽  
Yunfei Xu ◽  
Yi Zhao ◽  
Zhimin Li ◽  
Yang Liu ◽  
...  

Wax deposition during crude oil transmission can cause a series of negative effects and lead to problems associated with pipeline safety. A considerable number of previous works have investigated the wax deposition mechanism, inhibition technology, and remediation methods. However, studies on the shearing mechanism of wax deposition have focused largely on the characterization of this phenomena. The role of the shearing mechanism on wax deposition has not been completely clarified. This mechanism can be divided into the shearing dispersion effect caused by radial migration of wax particles and the shearing stripping effect caused by hydrodynamic scouring. From the perspective of energy analysis, a novel wax deposition model was proposed that considered the flow parameters of waxy crude oil in pipelines instead of its rheological parameters. Considering the two effects of shearing dispersion and shearing stripping coexist, with either one of them being the dominant mechanism, a shearing dispersion flux model and a shearing stripping model were established. Furthermore, a quantitative method to distinguish between the roles of shearing dispersion and shearing stripping in wax deposition was developed. The results indicated that the shearing mechanism can contribute an average of approximately 10% and a maximum of nearly 30% to the wax deposition process. With an increase in the oil flow rate, the effect of the shearing mechanism on wax deposition is enhanced, and its contribution was demonstrated to be negative; shear stripping was observed to be the dominant mechanism. A critical flow rate was observed when the dominant effect changes. When the oil flow rate is lower than the critical flow rate, the shearing dispersion effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. When the oil flow rate is higher than the critical flow rate, the shearing stripping effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. This understanding can be used to design operational parameters of the actual crude oil pipelines and address the potential flow assurance problems. The results of this study are of great significance for understanding the wax deposition theory of crude oil and accelerating the development of petroleum industry pipelines.


1967 ◽  
Vol 3 (8) ◽  
pp. 579-582
Author(s):  
N. M. Kaskevich
Keyword(s):  

Author(s):  
Yuanyuan Chen ◽  
Jing Gong ◽  
Xiaoping Li ◽  
Nan Zhang ◽  
Shaojun He ◽  
...  

Pipeline commissioning, which is a key link from engineering construction to production operation, is aim to fill an empty pipe by injecting water or oil to push air out of it. For a large-slope crude oil pipeline with great elevation differences, air is fairly easy to entrap at downward inclined parts. The entrapped air, which is also called air pocket, will cause considerable damage on pumps and pipes. The presence of it may also bring difficulties in tracking the location of the liquid head or the interface between oil and water. It is the accumulated air that needed to be exhausted in time during commissioning. This paper focuses on the simulation of liquid-gas replacement in commissioning process that only liquid flow rate exists while gas stays stagnant in the pipe and is demanded to be replaced by liquid. Few previous researches have been found yet in this area. Consequently, the flow in a V-section pipeline consisted of a downhill segment and a subsequent uphill one is used here for studying both the formation and exhaustion behaviors of the intake air. The existing two-fluid model and simplified non-pressure wave model for gas-liquid stratified flow are applied to performance the gas formation and accumulation. The exhausting process is deemed to be a period in which the elongated bubble (Taylor bubble) is fragmented into dispersed small bubbles. A mathematical model to account for gas entrainment into liquid slug is proposed, implemented and incorporated in a computational procedure. By taking into account the comprehensive effects of liquid flow rate, fluid properties, surface tension, and inclination angle, the characteristics of the air section such as the length, pressure and mass can be calculated accurately. The model was found to show satisfactory predictions when tested in a pipeline. The simulation studies can provide theoretical support and guidance for field engineering application, which are meanwhile capable of helping detect changes in parameters of gas section. Thus corresponding control measures can be adopted timely and appropriately in commissioning process.


2018 ◽  
Vol 160 ◽  
pp. 519-530 ◽  
Author(s):  
Qing Yuan ◽  
Changchun Wu ◽  
Bo Yu ◽  
Dongxu Han ◽  
Xinyu Zhang ◽  
...  

Author(s):  
V Brotóns ◽  
S Ivorra ◽  
R Tomás ◽  
J Martínez-Martínez ◽  
D Benavente
Keyword(s):  

2022 ◽  
Vol 2022 ◽  
pp. 1-7
Author(s):  
Erjian Wei ◽  
Bin Hu ◽  
Jing Li ◽  
Kai Cui ◽  
Zhen Zhang ◽  
...  

A rock creep constitutive model is the core content of rock rheological mechanics theory and is of great significance for studying the long-term stability of engineering. Most of the creep models constructed in previous studies have complex types and many parameters. Based on fractional calculus theory, this paper explores the creep curve characteristics of the creep elements with the fractional order change, constructs a nonlinear viscoelastic-plastic creep model of rock based on fractional calculus, and deduces the creep constitutive equation. By using a user-defined function fitting tool of the Origin software and the Levenberg–Marquardt optimization algorithm, the creep test data are fitted and compared. The fitting curve is in good agreement with the experimental data, which shows the rationality and applicability of the proposed nonlinear viscoelastic-plastic creep model. Through sensitivity analysis of the fractional order β2 and viscoelastic coefficient ξ2, the influence of these creep parameters on rock creep is clarified. The research results show that the nonlinear viscoelastic-plastic creep model of rock based on fractional calculus constructed in this paper can well describe the creep characteristics of rock, and this model has certain theoretical significance and engineering application value for long-term engineering stability research.


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