Abstract：The paper studied the measurement method for directivity of phased-array acoustic transmitter in acoustic log by experimental modeling method.Three phased-array acoustic transmitter in different structure used for acoustic log and relevant mufti-channel signal source are made by ourselves in laboratory and using high-precision positioning system and data acquisition system to measure the vertical directivity of each phased-array acoustic transmitter in the water.The experimental results showed that along with increasing the delay-time of impulsive signal on adjacent array elements,the steered radiation angle of acoustic beam of phasedarray becomes larger and larger.The direction of acoustic beam and angular width of main lobe can be changed by properly amplitude-weighting,decreasing the frequency of impulsive signal and adjusting the interval of array elements.Comparing the experimental results of directivity with theoretical computation has good consistence.The adjustable and controllable characters of acoustic direction and angular width of radiation main lobe in acoustic transmitter are of great importance to new generation of acoustic log and cross-hole seismic exploration.
