Acoustic telemetry along the drill string helps to know the physical and chemical characteristics of the formation and drilling fluid.A time-domain algorithm is developed for the propagation of one-dimensional axial s...Acoustic telemetry along the drill string helps to know the physical and chemical characteristics of the formation and drilling fluid.A time-domain algorithm is developed for the propagation of one-dimensional axial stress waves with the inner and outer viscous fluid.The algorithm simulates the passbands,stopbands and spikes due to the presence of the discontinuous boundaries of drill string.Then the effects of transmitted pulses and transceivers on acoustic transmission are analysed.The simulated results show that the raised cosine pulses and optimal placements of transceivers improve system performance.Moreover,dual PZT receivers can exclude signals propagating in a direction opposite to the transmitted signals. It is obvious that the uses of the available modeling and signal processing techniques can make the drill string as a waveguide for transmitting information at high data rates.展开更多
This paper describes the main principles of the non-contamination pumping pipe string, that is, use the perforated slip packer and the check valve to separate the cleanout liquid from the formation at certain location...This paper describes the main principles of the non-contamination pumping pipe string, that is, use the perforated slip packer and the check valve to separate the cleanout liquid from the formation at certain location at the lower part of the pump, so as to prevent the well cleanout liquid from killing the well and contaminating the oil reservoir.展开更多
文摘Acoustic telemetry along the drill string helps to know the physical and chemical characteristics of the formation and drilling fluid.A time-domain algorithm is developed for the propagation of one-dimensional axial stress waves with the inner and outer viscous fluid.The algorithm simulates the passbands,stopbands and spikes due to the presence of the discontinuous boundaries of drill string.Then the effects of transmitted pulses and transceivers on acoustic transmission are analysed.The simulated results show that the raised cosine pulses and optimal placements of transceivers improve system performance.Moreover,dual PZT receivers can exclude signals propagating in a direction opposite to the transmitted signals. It is obvious that the uses of the available modeling and signal processing techniques can make the drill string as a waveguide for transmitting information at high data rates.
文摘This paper describes the main principles of the non-contamination pumping pipe string, that is, use the perforated slip packer and the check valve to separate the cleanout liquid from the formation at certain location at the lower part of the pump, so as to prevent the well cleanout liquid from killing the well and contaminating the oil reservoir.
