The supercritical carbon dioxide （SC-CO2） jet can break rocks at higher penetration rates and lower threshold pressures than the water jet. The abrasive SC-CO2 jet, formed by adding solid particles into the SC-CO2 j...The supercritical carbon dioxide （SC-CO2） jet can break rocks at higher penetration rates and lower threshold pressures than the water jet. The abrasive SC-CO2 jet, formed by adding solid particles into the SC-CO2 jet, is expected to achieve higher operation efficiency in eroding hard rocks and cutting metals. With the computational fluid dynamics numerical simulation method, the characteristics of the flow field of the abrasive SC-CO2 jet are analyzed, as well as the main influencing factors. Results show that the two-phase axial velocities of the abrasive SC-CO2 jet is much higher than those of the abrasive water jet, when the pressure difference across the jet nozzle is held constant at 20 MPa, the optimal standoff distance for the largest particle impact velocity is approximately 5 times of the jet nozzle diameter; the fluid temperature and the volume concentration of the abrasive particles have modest influences on the two-phase velocities, the ambient pressure has a negligible influence when the pressure difference is held constant. Therefore the abrasive SC-CO2 jet is expected to assure more effective erosion and cutting performance. This work can provide guidance for subsequent lab experiments and promote practical applications.展开更多
As a new jet technology developed in recent years, the supercritical carbon dioxide（SC-CO2） jet technology enjoys many advantages when applied in oil and gas explorations. In order to study the properties and parame...As a new jet technology developed in recent years, the supercritical carbon dioxide（SC-CO2） jet technology enjoys many advantages when applied in oil and gas explorations. In order to study the properties and parametric influences of the SC-CO2 jet, the flow fields of the SC-CO2 jet are simulated using the computational fluid dynamics method. The flow field of the SC-CO2 is compared with that of the water jet. The influences of several parameters on the flow field of the SC-CO2 jet are studied. It is indicated that like the water jet, the velocity and the pressure of the SC-CO2 jet could be converted to each other, and the SC-CO2 jet can generate a significant impact pressure on the wall, the SC-CO2 jet has a stronger impact pressure and a higher velocity than those of the water jet under the same conditions, the maximum velocity and the impact pressure of the SC-CO2 jet increase with the increase of the nozzle pressure drop, under the stimulation condition of this study, the influence of the SC-CO2 temperature on the impact pressure can be neglected in engineering applications, while the maximum velocity of the SC-CO2 jet increases with the increase of the fluid temperature. This paper theoretically explores the properties of the SC-CO2 jet flow field, and the results might provide a theoretical basis for the application of the SC-CO2 jet in oil and gas well drillings and fracturing stimulations.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51304226)the National Key Basic Research Development Program of China(973 Program,Grant No.2014CB239203)
文摘The supercritical carbon dioxide （SC-CO2） jet can break rocks at higher penetration rates and lower threshold pressures than the water jet. The abrasive SC-CO2 jet, formed by adding solid particles into the SC-CO2 jet, is expected to achieve higher operation efficiency in eroding hard rocks and cutting metals. With the computational fluid dynamics numerical simulation method, the characteristics of the flow field of the abrasive SC-CO2 jet are analyzed, as well as the main influencing factors. Results show that the two-phase axial velocities of the abrasive SC-CO2 jet is much higher than those of the abrasive water jet, when the pressure difference across the jet nozzle is held constant at 20 MPa, the optimal standoff distance for the largest particle impact velocity is approximately 5 times of the jet nozzle diameter; the fluid temperature and the volume concentration of the abrasive particles have modest influences on the two-phase velocities, the ambient pressure has a negligible influence when the pressure difference is held constant. Therefore the abrasive SC-CO2 jet is expected to assure more effective erosion and cutting performance. This work can provide guidance for subsequent lab experiments and promote practical applications.
基金Project supported by the National Key Basic Research Development Program of China(973 Program,Grant No.2014CB239203)the National Natural Science Foundation of China(Grant No.51304226)
文摘As a new jet technology developed in recent years, the supercritical carbon dioxide（SC-CO2） jet technology enjoys many advantages when applied in oil and gas explorations. In order to study the properties and parametric influences of the SC-CO2 jet, the flow fields of the SC-CO2 jet are simulated using the computational fluid dynamics method. The flow field of the SC-CO2 is compared with that of the water jet. The influences of several parameters on the flow field of the SC-CO2 jet are studied. It is indicated that like the water jet, the velocity and the pressure of the SC-CO2 jet could be converted to each other, and the SC-CO2 jet can generate a significant impact pressure on the wall, the SC-CO2 jet has a stronger impact pressure and a higher velocity than those of the water jet under the same conditions, the maximum velocity and the impact pressure of the SC-CO2 jet increase with the increase of the nozzle pressure drop, under the stimulation condition of this study, the influence of the SC-CO2 temperature on the impact pressure can be neglected in engineering applications, while the maximum velocity of the SC-CO2 jet increases with the increase of the fluid temperature. This paper theoretically explores the properties of the SC-CO2 jet flow field, and the results might provide a theoretical basis for the application of the SC-CO2 jet in oil and gas well drillings and fracturing stimulations.
