Downhole pulsation system and method

A downhole pulsation system for utilization with a drill string, said system comprising:

• a valve assembly comprising:
• a valve sub housing attachable to the drill string, the valve sub housing including a sub bore axially extending along a longitudinal axis therethrough and configured to allow fluid to pass therethrough;
• a lobed insert fittable to said valve sub housing and locatable inside said sub bore, said lobed insert including an insert bore axially extending along a longitudinal axis therethrough and configured to allow fluid to pass therethrough, and at least one lobe feature extending into said insert bore;
• and
• a mandrel cap including a cap bore axially extending along a longitudinal axis therethrough and configured to allow fluid to pass therethrough, and at least one port defined through said mandrel cap in communication with said cap bore, said mandrel cap having a portion thereof rotatably receivable in said insert bore of said lobed insert so that said port is alignable with said lobe feature;
• a mandrel connectable to said mandrel cap, said mandrel including a mandrel bore axially extending along a longitudinal axis therethrough and configured to allow fluid to pass therethrough from said cap bore, and at least one mandrel port defined through said mandrel in communication with said mandrel bore and configured to allow fluid to pass from said mandrel bore to an annulus defined exterior of at least a portion of said mandrel defining said mandrel port;
• at least one drive linkage connectable to said mandrel;
• a rotor connectable to said drive linkage, said rotor having at least one rotor lobe;
• and
• a stator including a stator bore axially extending along a longitudinal axis therethrough and configured to allow fluid to pass therethrough, and at least one stator lobe, said stator bore being configured receive said rotor;
• wherein said mandrel cap being rotated by said rotor to intermittently allow fluid or portion of the fluid to pass from said insert bore through said port.

A method of creating drill string pulsation utilizing a downhole pulsation system, said method comprising the steps of:

• a) receiving a working fluid to a sub bore axially defined along a longitudinal axis of a valve sub housing from an axial bore of a drill string coupled to said valve sub housing;
• b) receiving the working fluid to a cap bore defined along a longitudinal axis of a mandrel cap that is rotatably received in an insert bore of a lobed insert located in said sub bore of said valve sub housing;
• c) flowing the working fluid through said cap bore and to a mandrel bore axially defined along a longitudinal axis of a mandrel coupled to said mandrel cap;
• d) flowing the working fluid from said mandrel bore through at least one mandrel port that is in communication with the mandrel bore and an annulus defined exterior of at least a portion of said mandrel defining said mandrel port;
• e) rotating a rotor within a stator bore of a stator utilizing the flowing of the working fluid through said stator bore, said rotor being connected to said mandrel;
• and
• f) rotating said mandrel cap by rotation of said rotor so that a mandrel port is intermittently obstructed by a lobe feature of said lobed insert.