Effect Of Wellbore Temperature Distribution On Brine Crystallization In Salt Cavern Storage Wellbore

The problem of brine crystallization in salt cavern storage displacement string extends the construction period and increases the project cost.Aiming at this problem,based on the thermodynamics principle,the crystal growth theory,by adopting the experimental study and numerical simulation method,I carried out the crystallization experiments of different temperature and wall surface properties,explored the influence of temperature and the wall surface properties on the crystallization regularity,and analysed the wellbore temperature field under the condition of the reverse circulation in the single well of the salt cavern storage,explored the influence of the injection fluid rate,injection fluid temperature,center pipe properties on wellbore temperature distribution,and then get the crystallization rule in the salt cavern storage displacement string.The main conclusions are:(1)the effect of supersaturation on the crystallization of brine in wellbore is the most significant,and the temperature can affect the oversaturation state of saturated solution.(2)the smoothness of the wall surface of the string is not easy to allow the crystal to grow on the wall.(3)compared with the natural cooling of brine,the contact between brine and the tube wall of lower temperature makes the crystal more easily generated and adsorbed on the wall surface.(4)Using thermal insulation pipe,increasing injection fluid temperature,and increasing injection fluid rate can reduce the cooling range to a certain extent,and reduce the temperature difference between the brine and the central pipe in the wellbore,but the effect of using the thermal insulation pipe(such as the glass tube,insulated tubing,etc.)is better.The research results are expected to provide references for the selection of the related preventive measures for the brine crystallization in displacement string.