STUDY ON TRANSMISSION CHARACTERISTICS OF MUD PULSE WAVES USED FOR TRANSMITTING INFORMATION FROM DOWNHOLE TO SURFACE IN DRILLING ENGINEERING

摘要

In oil and gas drilling engineering, the drilling tool is driven into the earth from a drilling rig to create a wellbore through which hydrocarbons are passed. During the drilling process, it is desirable to collect downhole information about the drilling operation as well as the underground formations. Sensors are provided mainly in various portions of the downhole systems to obtain data about the trajectory, the earth formations, the operating conditions, and so on. The data is collected and analyzed so that decisions may be made concerning the drilling operation and the earth formations. So a key element of the steering process is the real-time measurement and transmission of the near-bit information from the bottom of the well to surface. The most commercial systems in drilling engineering for transmitting data to surface is to produce mud pressure pulses within the portion of the drilling mud enclosed in the hollow drillstring. In this technique, telemetry signals are encoded as mud wave pulses that propagate through the inside of drillstring and are subsequently received and converted back to electric signals for data recovery at the surface receiver. Based on the theoretical analysis, this paper will highlight the improvement of technical development.