Mud-pulse telemetry system including pulser for transmitting information along drill string

The invention discloses a rotary pulser and method. The rotary pulser includes a housing, a stator supported by the housing, a rotor adjacent to the downhole end of the stator, and a motor assembly coupled to the rotor. A controller may receive a signal that includes drilling information. In response to receiving the signal, the controller causes the motor assembly to rotate the rotor in a first rotational direction through a rotation cycle. The rotation cycle a) rotates the rotor from a first position, where the rotor does not obstruct the at least one passage, into a second position, where the rotor obstructs the at least one passage, and b) rotates the rotor from the second position to a third position in the first rotational direction. Rotation of the rotor generates a pressure pulse in the drilling fluid. 本发明公开了种旋转式脉冲发生器和方法，旋转式脉冲发生器包括壳体、由壳体支承的定子、与定子的井下端相邻的转子以及联接至转子的马达组件。控制器可以接收包括钻井信息的信号。控制器响应于接收到信号而致使马达组件使转子沿第旋转方向旋转经过旋转周期。旋转周期a)使转子从第位置旋转到第二位置，在第位置中，转子不阻挡至少个通道，在第二位置中，转子阻挡所述至少个通道，以及b)使转子沿第旋转方向从第二位置旋转到第三位置。