Downhole vibratory apparatus

1. A vibratory downhole rotary apparatus having a fluid passage flow area, the apparatus comprising:

a cylindrical hollow body having a first end and a second end;

a stator disposed within the cylindrical hollow body;

a rotor rotatably disposed within the stator;

a rotatable fluid passage body attached to the rotor and disposed within the cylindrical hollow body, the rotatable fluid passage body having a fluid passage opening therein;

a fluid flow restrictor positioned adjacent to the rotatable fluid passage body and disposed within the cylindrical hollow body, the fluid flow restrictor causing alternating increasing and decreasing flow resistance to fluid flowing through the apparatus; and

wherein the fluid passage flow area of the apparatus is constant.

2. The apparatus of claim 1 wherein the fluid passage opening is cylindrically shaped and has a diameter that decreases in the direction from the first end towards the second end of the cylindrical hollow body.

3. The apparatus of claim 1 wherein the fluid flow restrictor comprises:

a vortex chamber;

a plurality of fluid inlet ports in fluid communication with the vortex chamber; and

an outlet disposed in the vortex chamber to permit fluid to exit the vortex chamber and ultimately exit the second end of the cylindrical hollow body.

4. The apparatus of claim 3 wherein the fluid flow restrictor includes:

a first inlet port in fluid communication with the vortex chamber, the first inlet port positioned such that during rotation of the rotatable fluid passage body, the fluid passage opening is temporarily aligned with the first inlet port which allows fluid to enter the vortex chamber and create a clockwise vortex therein and increase the backpressure across the apparatus; and

a second inlet port in fluid communication with the vortex chamber, the first inlet port positioned such that during rotation of the rotatable fluid passage body, the fluid passage opening is temporarily aligned with the second inlet port which allows fluid to enter the vortex chamber and create a counter-clockwise vortex therein and increase the backpressure across the apparatus.

5. The apparatus of claim 4 wherein the first inlet port and the second inlet port are positioned relative to the vortex chamber such that fluid is directed substantially tangentially into the vortex chamber.

6. The apparatus of claim 4 wherein the second inlet port is positioned relative to the vortex chamber such that fluid is directed towards a center portion of the vortex chamber.

7. The apparatus of claim 1 wherein the stator is constructed of elastomeric materials or substantially metallic materials.

8. The apparatus of claim 1 wherein the fluid flow restrictor is disposed within a lower thrust bearing that is disposed within the second end of the cylindrical hollow body and adjacent to the rotatable fluid passage body, the lower thrust bearing sustaining rotational and sliding contact with the rotatable fluid passage body when the rotatable fluid passage body rotates.