In drilling operation, a large saving in time and money would be achieved by reducing the drilling time, since some of the costs are time-dependent. Drilling time could be minimized by raising the penetration rate. In...In drilling operation, a large saving in time and money would be achieved by reducing the drilling time, since some of the costs are time-dependent. Drilling time could be minimized by raising the penetration rate. In the comparative optimization method, by using the records of the first drilled wells and comparing the criteria like penetration rate, cost per foot and specific energy, the drilling parameters of the next wells being drilled can be optimized in each depth interval. In the mathematical optimization technique, some numerical equations to model the penetration rate, bit wear rate and hydraulics would be used to minimize the drilling cost and time as much as possible and improve the results of the primary comparative optimization. In this research, as a case study the Iranian Khangiran gas field has been evaluated to optimize the drilling costs. A combination of the mentioned optimization techniques resulted in an optimal well which reduced the drilling time and cost considerably in comparison with the wells already drilled.展开更多
In this work we have investigated electron and hole transport through zig zag carbon nanotubes by solving Boltzmann Transport Equation(BTE).We find that the mobility of electrons is rather greater than holes.Carbo nan...In this work we have investigated electron and hole transport through zig zag carbon nanotubes by solving Boltzmann Transport Equation(BTE).We find that the mobility of electrons is rather greater than holes.Carbo nanotubes with longer diameter can carry higher current.Normally,transport of electrons(or holes) is dominated by scattering events,which relax the carrier momentum in an effort to bring the conducting material to equilibrium.展开更多
文摘In drilling operation, a large saving in time and money would be achieved by reducing the drilling time, since some of the costs are time-dependent. Drilling time could be minimized by raising the penetration rate. In the comparative optimization method, by using the records of the first drilled wells and comparing the criteria like penetration rate, cost per foot and specific energy, the drilling parameters of the next wells being drilled can be optimized in each depth interval. In the mathematical optimization technique, some numerical equations to model the penetration rate, bit wear rate and hydraulics would be used to minimize the drilling cost and time as much as possible and improve the results of the primary comparative optimization. In this research, as a case study the Iranian Khangiran gas field has been evaluated to optimize the drilling costs. A combination of the mentioned optimization techniques resulted in an optimal well which reduced the drilling time and cost considerably in comparison with the wells already drilled.
文摘In this work we have investigated electron and hole transport through zig zag carbon nanotubes by solving Boltzmann Transport Equation(BTE).We find that the mobility of electrons is rather greater than holes.Carbo nanotubes with longer diameter can carry higher current.Normally,transport of electrons(or holes) is dominated by scattering events,which relax the carrier momentum in an effort to bring the conducting material to equilibrium.
