Selectively activated friction reduction tool and method

A method of selectively generating a pressure pulse in a downhole string, comprising the steps of:

• a) providing one or more selectively activated friction reduction tools each comprising:
• a power assembly;
• a valve assembly operatively connected downstream of the power assembly, the valve assembly including a rotating valve segment and a stationary valve segment;
• and an activation assembly operatively connected downstream of the power assembly, wherein in a first position the activation assembly provides a bypass flow path around the valve assembly for at least a portion of the media flow, wherein the activation assembly is configured to transition from the first position to a second position in response to a variation in an operating condition of the media flow, wherein in the second position of the activation assembly the bypass flow path is substantially closed;
• wherein the power assembly is configured to rotate the rotating valve segment in relation to the stationary valve segment upon a media flow through the power assembly;
• wherein the valve assembly is configured to generate significant pressure pulses in a media flow column with the rotation of the rotating valve segment only when the activation assembly is in the second position;
• b) securing the one or more friction reduction tools with the activation assembly in the first position between segments of the downhole string;
• wherein the downhole string includes a drill string or a coiled tubing line;
• c) lowering the downhole string with the one or more friction reduction tools into a wellbore;
• d) pumping a media through the downhole string and the one or more friction reduction tools;
• wherein the media causes the power assembly of each friction reduction tool to rotate the rotating valve segment of the valve assembly;
• wherein at least a portion of the media flows through the bypass flow path around the valve assembly when the activation assembly is in the first position;
• wherein no significant pressure pulse is generated by the valve assembly with the activation assembly in the first position;
• e) selectively activating an activated friction reduction tool selected from the one or more friction reduction tools while positioned within the wellbore by varying the operating condition of the media to transition the activation assembly of the activated friction reduction tool from the first position to the second position in which the bypass flow path is substantially closed, wherein varying the operating condition of the media comprises increasing a flow rate of the media, or increasing a density of the media, or increasing a viscosity of the media, or a combination of increasing the flow rate of the media, increasing the density of the media, and increasing the viscosity of the media;
• and
• f) continuing to pump media through the downhole string and the one or more friction reduction tools with the activation assembly of the activated friction reduction tool in the second position;
• wherein the media continues to cause the power assembly to rotate the rotating valve segment of the valve assembly and substantially all of the media flows through the valve assembly with the activation assembly in the second position in the activated friction reduction tool;
• wherein
• the rotation of the rotating valve segment of the valve assembly in the activated friction reduction tool generates significant pressure pulses that are transmitted to the downhole string.