The Downhole Transmission Characteristics of Vibration Waves — An Experimental Study in the Daqing Oil Field

Abstract The downhole communication is the key technology of reservoir exploitation and downhole remote control. The vibration wave communication method provides a new way for the downhole data transmission. Using this method, control commands can be modulated and transmitted through the tubing or casing by the vibration wave. To analyzing the downhole transmission characteristics of vibration waves, a field test was implemented in the Daqing oil field. The vibration signal generator, located on the wellhead, can convert the electricity into the vibration wave by using the magnetostrictive material. The vibration wave signal is transmitted through the casing. To receive and test the signal, a signal detection device is developed. The signal detection device can be fixed on the casing firmly at any depth by a motor-activated-ram mechanism. A cable is plugged into the signal detection device, with which the detected vibration wave signals and the decoded signals can be transferred to the computer on the ground. By analyzing the received signals, the following conclusions are drawn: (1) At the depth of 900 meters, the vibration wave signal can be received and decoded correctly, which verifies the feasibility of the vibration wave downhole communication method. (2) Detection failure of vibration waves of certain frequencies occurs at specific depths. This phenomenon proves the characteristic of alternating passband and stopband in vibration wave transmission, which also validates the reliability of the multi-fundamental-frequency transmission strategy. (3) The attenuation characteristic of the vibration wave is obtained. With its low cost, convenient operation and high reliability, the vibration wave downhole communication technology can be widely used in hydraulic fracturing, water flooding and zonal production.