In the present study,a large set of data related to well killing is considered.Through a complete exploration of the whole process leading to well-killing,various factors affecting such a process are screened and sort...In the present study,a large set of data related to well killing is considered.Through a complete exploration of the whole process leading to well-killing,various factors affecting such a process are screened and sorted,and a correlation model is built accordingly in order to introduce an auxiliary method for well-killing monitoring based on statistical information.The available data show obvious differences due to the diverse control parameters related to different well-killing methods.Nevertheless,it is shown that a precise three-fold relationship exists between the reservoir parameters,the elapsed time and the effectiveness of the considered well-killing strategy.The proposed monitoring auxiliary method is intended to support risk assessment and optimization in the context of typical well-killing applications.展开更多
The behavior of hydrogen （H） in metals has been a long- standing research topic in materials science. One of the most compelling subjects is the deleterious effects of H on the microstructural evolution of materials...The behavior of hydrogen （H） in metals has been a long- standing research topic in materials science. One of the most compelling subjects is the deleterious effects of H on the microstructural evolution of materials; these effects include H embrittlement, superabundant vacancy formation, and blistering. Vacancies have been demonstrated through both experiments and computational simulations to have strong H trapping effects [1], resulting in increased H retention [2], gas-filled bubble formation [3-5], and surface modification [6-9]. In addition, at high temperatures and high H pressures, superabundant vacancy formation induced by H is observed [ 10,11 ]. Unfortunately, even though substantial research has been conducted on the interplay between H and vacancies [12-14], the detailed processes by which H-vacancy com- plexes nucleate, grow, and agglomerate remain unclear. In these processes, the energetics and structures of H-vacancy clusters are undoubtedly important.展开更多
We have developed an object kinetic Monte Carlo(OKMC)code and simulated hydrogen-vacancy clustering behavior and dependence on temperature and hydrogen-vacancy ratio in tungsten.For each of the temperatures we simulat...We have developed an object kinetic Monte Carlo(OKMC)code and simulated hydrogen-vacancy clustering behavior and dependence on temperature and hydrogen-vacancy ratio in tungsten.For each of the temperatures we simulated from 300 K to1000 K,H_nV clusters with smaller n form before those with larger n.The elevating temperature leads to a decrease in hydrogen vacancies:H_(10)V and H_9V clusters dominate at 300 K and 600 K,whereas H_5V,H_6V,and H_7V clusters dominate when the temperature reaches 1000 K.Furthermore,only H_nV clusters with smaller n formed when a lower hydrogen-vacancy ratio was used due to insufficient availability of hydrogen atoms to occupy vacancies.The results suggest hydrogen emission occurs very rarely at lower temperatures,while higher temperatures facilitate the dissociation of hydrogen from H_nV clusters.展开更多
We investigate the interaction between <111> self-interstitial atoms(SIAs) and 1/2<111> self-interstitial dislocation loops in tungsten(W) via atomistic simulations. We explore the variation of the anisotr...We investigate the interaction between <111> self-interstitial atoms(SIAs) and 1/2<111> self-interstitial dislocation loops in tungsten(W) via atomistic simulations. We explore the variation of the anisotropic distribution of binding energies with the shapes and sizes of the 1/2[111] loop and the nonequivalent configurations of <111> SIAs. For an arbitrarily shaped loop, SIA can be more easily trapped in the concave region of the loop than the convex region, which forms a loop whose curvature is closer to that of a circular loop. The direction of SIAs can largely affect the interaction behaviors with the loop. The capture distance of an SIA by the edge of a circular-shaped 1/2[111] loop is clearly elongated along the direction of the SIA;however, it weakly depends on the size of the loop. Then, we analyze the slanted ring-like capture volume of <111> SIAs formed by the circular loop based on their generated anisotropic stress fields. Furthermore, the binding energies obtained from the elastic theory and atomistic simulations are compared. The results provide a reasonable interpretation of the growth mechanism of the loop and the anisotropic interaction that induces irregular-shaped capture volume, affording an insight into the numerical and Object Kinetic Monte Carlo simulations to evaluate the long-term and large-scale microstructural evolution and mechanical properties of W.展开更多
W is considered a potential candidate as a plasma facing ma- terial for future nuclear fusion devices because of its high melting point, low sputtering rate, and low H or He solubility [1-3]. In a fusion environment, ...W is considered a potential candidate as a plasma facing ma- terial for future nuclear fusion devices because of its high melting point, low sputtering rate, and low H or He solubility [1-3]. In a fusion environment, W will be in direct contact with heat flux, H/He particle fluxes, and the irradiation of high-energy neutrons, causing several defects to be generated, which decrease the service life of W materials. The grain boundary （GB）, which is an important type of defect, affects the various physical and mechanical properties of ma- terials. In the nuclear environment, the GB can act as a sink for the defects when the material is under irradiation.展开更多
基金supported by research on key equipment and supporting technology for Onshore Well Control Emergency,CNPC(2021ZZ03-2).
文摘In the present study,a large set of data related to well killing is considered.Through a complete exploration of the whole process leading to well-killing,various factors affecting such a process are screened and sorted,and a correlation model is built accordingly in order to introduce an auxiliary method for well-killing monitoring based on statistical information.The available data show obvious differences due to the diverse control parameters related to different well-killing methods.Nevertheless,it is shown that a precise three-fold relationship exists between the reservoir parameters,the elapsed time and the effectiveness of the considered well-killing strategy.The proposed monitoring auxiliary method is intended to support risk assessment and optimization in the context of typical well-killing applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.51720105006,and 11675009)the Science Challenge Project(Grant No.JCKY2016212A502)
文摘The behavior of hydrogen （H） in metals has been a long- standing research topic in materials science. One of the most compelling subjects is the deleterious effects of H on the microstructural evolution of materials; these effects include H embrittlement, superabundant vacancy formation, and blistering. Vacancies have been demonstrated through both experiments and computational simulations to have strong H trapping effects [1], resulting in increased H retention [2], gas-filled bubble formation [3-5], and surface modification [6-9]. In addition, at high temperatures and high H pressures, superabundant vacancy formation induced by H is observed [ 10,11 ]. Unfortunately, even though substantial research has been conducted on the interplay between H and vacancies [12-14], the detailed processes by which H-vacancy com- plexes nucleate, grow, and agglomerate remain unclear. In these processes, the energetics and structures of H-vacancy clusters are undoubtedly important.
基金supported by the National Natural Science Foundation of China(Grant Nos.11675009,and 51720105006)the Science Challenge Project(Grant No.JCKY 2016212A502)
文摘We have developed an object kinetic Monte Carlo(OKMC)code and simulated hydrogen-vacancy clustering behavior and dependence on temperature and hydrogen-vacancy ratio in tungsten.For each of the temperatures we simulated from 300 K to1000 K,H_nV clusters with smaller n form before those with larger n.The elevating temperature leads to a decrease in hydrogen vacancies:H_(10)V and H_9V clusters dominate at 300 K and 600 K,whereas H_5V,H_6V,and H_7V clusters dominate when the temperature reaches 1000 K.Furthermore,only H_nV clusters with smaller n formed when a lower hydrogen-vacancy ratio was used due to insufficient availability of hydrogen atoms to occupy vacancies.The results suggest hydrogen emission occurs very rarely at lower temperatures,while higher temperatures facilitate the dissociation of hydrogen from H_nV clusters.
基金supported by the National Natural Science Foundation of China(Grant Nos.51871007,11675230,and 12075021)the National MCF Energy R&D Program of China(Grant No.2018YFE0308103)。
文摘We investigate the interaction between <111> self-interstitial atoms(SIAs) and 1/2<111> self-interstitial dislocation loops in tungsten(W) via atomistic simulations. We explore the variation of the anisotropic distribution of binding energies with the shapes and sizes of the 1/2[111] loop and the nonequivalent configurations of <111> SIAs. For an arbitrarily shaped loop, SIA can be more easily trapped in the concave region of the loop than the convex region, which forms a loop whose curvature is closer to that of a circular loop. The direction of SIAs can largely affect the interaction behaviors with the loop. The capture distance of an SIA by the edge of a circular-shaped 1/2[111] loop is clearly elongated along the direction of the SIA;however, it weakly depends on the size of the loop. Then, we analyze the slanted ring-like capture volume of <111> SIAs formed by the circular loop based on their generated anisotropic stress fields. Furthermore, the binding energies obtained from the elastic theory and atomistic simulations are compared. The results provide a reasonable interpretation of the growth mechanism of the loop and the anisotropic interaction that induces irregular-shaped capture volume, affording an insight into the numerical and Object Kinetic Monte Carlo simulations to evaluate the long-term and large-scale microstructural evolution and mechanical properties of W.
基金supported by the National Magnetic Confinement Fusion Program(Grant No.2013GB109002)the National Natural Science Foundation of China(Grant Nos.51171008,and 51325103)
文摘W is considered a potential candidate as a plasma facing ma- terial for future nuclear fusion devices because of its high melting point, low sputtering rate, and low H or He solubility [1-3]. In a fusion environment, W will be in direct contact with heat flux, H/He particle fluxes, and the irradiation of high-energy neutrons, causing several defects to be generated, which decrease the service life of W materials. The grain boundary （GB）, which is an important type of defect, affects the various physical and mechanical properties of ma- terials. In the nuclear environment, the GB can act as a sink for the defects when the material is under irradiation.
