Petroleum Science >2008,??Issue 3:??266-270 DOI: https://doi.org/10.1007/s12182-009-0042-8
Numerical modeling of DPSK pressure signals and their transmission characteristics in mud channels Open?Access
文章信息
作者：Shen Yue,Su Yinao,Li Gensheng,Li Lin and Tian Shouceng
作者單位：
College of Physics Science and Technology, China University of Petroleum, Dongying, Shandong 257061, China;CNPC Drilling Research Institute, Beijing 100083, China;State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;CNPC Drilling Research Institute, Beijing 100083, China;State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China
投稿時間：2008-09-22
引用方式：Shen, Y., Su, Y., Li, G. et al. Pet. Sci. (2009) 6: 266. https://doi.org/10.1007/s12182-009-0042-8
文章摘要
A numerical model and transmission characteristic analysis of DPSK (differential phase shift keying) pressure signals in mud channels is introduced. With the control logic analysis of the rotary valve mud telemetry, a logical control signal is built from a Gate function sequence according to the binary symbols of transmitted data and a phase-shift function is obtained by integrating the logical control signal. A mathematical model of the DPSK pressure signal is built based on principles of communications by modulating carrier phase with the phase-shift function and a numerical simulation of the pressure wave is implemented with the mathematical model by MATLAB programming. Considering drillpipe pressure and drilling fluid temperature profile along drillpipes, the drillpipe of a vertical well is divided into a number of sections. With water-based drilling fluids, the impacts of travel distance, carrier frequency, drillpipe size, and drilling fluids on the signal transmission were studied by signal transmission characteristic analysis for all the sections. Numerical calculation results indicate that the influences of the viscosity of drilling fluids and volume fraction of gas in drilling fluids on the DPSK signal transmission are more notable than the others and the signal will distort in waveform with differential attenuations of the signalfrequent component.
關鍵詞
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Measurement while drilling (MWD), modulation, binary symbol, mathematical model, numerical simulation, differential phase shift keying (DPSK), signal transmission characteristics