The weight loss of cement slurry is the main cause of early annular air channeling and accurate experimental evaluation of the law of loss change is the key to achieve compression stability and prevent this undesired ...The weight loss of cement slurry is the main cause of early annular air channeling and accurate experimental evaluation of the law of loss change is the key to achieve compression stability and prevent this undesired phenomenon.Typically,tests on the pressure loss of cement slurry are carried out for temperature smaller than 120°C,and this condition cannot simulate effectively the situation occurring in high temperature wells.For this reason,in this study a series of experimental tests have been conducted considering a larger range of temperatures,different retarders and fluid loss additives.The results show that with an increase in the temperature,the weight loss curve of cement slurry changes from a“two-stage”to a“three-stage”behavior,and the risk of channeling increases accordingly.On increasing the amount of retarder and fluid loss additive,the transition time of cement slurry displays a non-monotonic behavior(it decreases first and then increases).It is found that the optimized retarder and fluid loss additive dosage are 0.2%and 2.5%,respectively.展开更多
The special purpose Monte Carlo program McMesh was used to study neutron transport in coal slurries for on stream determination of the slurry parameters. McMesh uses the mesh weight window method as the major variance...The special purpose Monte Carlo program McMesh was used to study neutron transport in coal slurries for on stream determination of the slurry parameters. McMesh uses the mesh weight window method as the major variance reduction technique with other methods such as exponential transforms and correlated sampling included as options. There was good agreement between the calculated results from McMesh and from MCNP, a general Monte Carlo program, but McMesh was more efficient and more convenient.展开更多
基金The authors gratefully acknowledge the research project from“Research and test on optimization of calculation model for cementing engineering of high temperature and high pressure wells”(Grant No.CQCJ-2020-06).
文摘The weight loss of cement slurry is the main cause of early annular air channeling and accurate experimental evaluation of the law of loss change is the key to achieve compression stability and prevent this undesired phenomenon.Typically,tests on the pressure loss of cement slurry are carried out for temperature smaller than 120°C,and this condition cannot simulate effectively the situation occurring in high temperature wells.For this reason,in this study a series of experimental tests have been conducted considering a larger range of temperatures,different retarders and fluid loss additives.The results show that with an increase in the temperature,the weight loss curve of cement slurry changes from a“two-stage”to a“three-stage”behavior,and the risk of channeling increases accordingly.On increasing the amount of retarder and fluid loss additive,the transition time of cement slurry displays a non-monotonic behavior(it decreases first and then increases).It is found that the optimized retarder and fluid loss additive dosage are 0.2%and 2.5%,respectively.
文摘The special purpose Monte Carlo program McMesh was used to study neutron transport in coal slurries for on stream determination of the slurry parameters. McMesh uses the mesh weight window method as the major variance reduction technique with other methods such as exponential transforms and correlated sampling included as options. There was good agreement between the calculated results from McMesh and from MCNP, a general Monte Carlo program, but McMesh was more efficient and more convenient.
