Downhole well conditioning tool

Abstract

A downhole well conditioning tool for self-stimulating a well is provided. The down hole tool is a multi-stage stacked self-exciting tool that can alter a relatively steady flow of incoming fluid into pulsating fluid streams of rapidly cycling high and low pressure without the use of moving internal parts. The downhole tool can include a first stage operative to receive a steady flow of pressurized fluid though an inlet and discharge a pulsating fluid flow and a second stage connected to the first stage and operative to receive the pulsating fluid flow from the first stage and increase the pulsations of the fluid flow before the pulsating fluid flow is discharged out of the second stage.

1 . A downhole tool comprising:
 a first stage operative to receive a steady flow of pressurized fluid though an inlet and discharge a pulsating fluid flow; and   a second stage connected to the first stage and operative to receive the pulsating fluid flow from the first stage and increase the pulsations of the fluid flow before the pulsating fluid flow is discharged out of the second stage.   
     
     
         2 . The downhole tool of  claim 1  wherein pulsating fluid flow discharged from the second stage is discharged at an angle to a centerline of the first second stage. 
     
     
         3 . The downhole tool of  claim 1  wherein the first stage comprises a sub having:
 a generally tubular body with a top end and a bottom end; 
 a fluid inlet at the top end; 
 a single fluid outlet at the bottom end; and 
 a plurality of passages fluidly connecting the inlet at the top end and the single outlet at the bottom end, the plurality of passages configured to induce pressure pulses in a steady stream of fluid entering the sub through the inlet at the top end and discharge the fluid as a single pulsating stream through the single fluid outlet. 
 
     
     
         4 . The downhole tool of  claim 3  wherein the top end has external threads and the bottom end has internal threads. 
     
     
         5 . The downhole tool of  claim 3 , wherein the sub further comprises:
 a first chamber immediately downstream from the fluid inlet;   two diffuser passages having openings in the first chamber, each diffuser angling outwards from a central axis of the sub as the two diffuser passages extend from the first chamber;   a transvers passage running between the two diffuser passages and opening into each of the two diffuser passages; and   a single central passage, both of the diffuser passages exiting into the single central passage, the single central passage connected to the single fluid outlet at the bottom end of the sub,   wherein the two diffuser passages change direction and angle in towards the central axis of the sub downstream from the transverse passage.   
     
     
         6 . The downhole tool of  claim 5  wherein the sub further comprises a wedge shaped splitter formed between the two diffuser passages. 
     
     
         7 . The downhole tool of  claim 6  wherein the wedge shaped splitter having has a flat front surface. 
     
     
         8 . The downhole tool of  claim 1  wherein the second stage comprises a nose having a top end and a bottom end. 
     
     
         9 . The downhole tool of  claim 8  wherein an inlet is provided in the top end of the nose to receive the pulsating fluid flow from the first stage and at least one port is provided in the bottom end of the nose. 
     
     
         10 . The downhole tool of  claim 8  wherein the bottom end of the nose has a semi-spherical shape. 
     
     
         11 . The downhole too of  claim 4  wherein a top end of the nose has external threads and the top end of the nose mates with the bottom end of the sub to form a pulsation chamber. 
     
     
         12 . The downhole tool of  claim 11  wherein the inlet in the top end of the nose is in fluid communication with the pulsation chamber. 
     
     
         13 . The downhole tool of  claim 11  wherein the nose further comprises:
 a central bore connected to the inlet in the top end of the nose; and 
 at least one outlet passage extending from the central bore to the at least one outlet port. 
 
     
     
         14 . The downhole tool of  claim 13  wherein the central bore of the nose extends along a central axis of the nose. 
     
     
         15 . The downhole tool of  claim 13  wherein the central bore of the nose is aligned with the central axis of the nose. 
     
     
         16 . The downhole tool of  claim 13  wherein the top end of the nose has a circular flat central portion surrounding the inlet. 
     
     
         17 . The downhole tool of  claim 16  wherein a tapered shoulder is provided extending downwards and outwards from the circular flat central portion on the top end of the nose to a flat shoulder surrounding the circular flat central portion and the tapered shoulder. 
     
     
         18 . The downhole tool of  claim 17  wherein the flat shoulder extends from a base of the tapered shoulder to an outer diameter of the nose. 
     
     
         19 . The downhole tool of  claim 13  wherein the at least one outlet passage extends downwards from where the at least one outlet passage connects with the central bore and at an angle to the central axis of the nose. 
     
     
         20 . The downhole tool of  claim 13  wherein the at least one outlet passage extends substantially radially outwards from where the at least one outlet passage connects with the central bore. 
     
     
         21 . The downhole tool of  claim 12  wherein the pulsation chamber is symmetrical around a central axis of the nose. 
     
     
         22 . The downhole tool of  claim 13  wherein the pulsation chamber has a larger diameter than the central bore. 
     
     
         23 . The downhole tool of  claim 11  wherein the central axis of the sub is aligned with the central axis of the nose. 
     
     
         24 . The downhole tool of  claim 18  wherein the external threads are provided on the outer diameter of the nose. 
     
     
         25 . A downhole tool comprising:
 a first stage comprising a sub having: a generally tubular body with a top end and a bottom end; a fluid inlet at the top end; a single fluid outlet at the bottom end; and a plurality of passages fluidly connecting the inlet at the top end and the single outlet at the bottom end, the plurality of passages configured to induce pressure pulses in a steady stream of fluid entering the sub through the inlet at the top end and discharge the fluid as a single pulsating stream through the single fluid outlet; and   a second stage connected to the first stage, the second stage comprising a nose having: a top end; a bottom end; an inlet provided in the top end of the nose to receive the pulsating fluid flow from the first stage; and at least one port is provided in the bottom end of the nose,   wherein the top end of the nose has external threads and the top end of the nose mates with the bottom end of the sub to form a pulsation chamber, and wherein the inlet in the top end of the nose is in fluid communication with the pulsation chamber, and wherein the at least one port of the nose is in fluid communication with the pulsation chamber.