Reciprocating downhole pump

Abstract

A reciprocating pump for use in a wellbore is disclosed. The pump includes a fluid directing apparatus for directing fluid in and out of the pump, the fluid directing apparatus having an inlet disposed in a sidewall of the fluid directing apparatus and an outlet. The pump also includes a piston disposed in a fluid housing and a piston driving apparatus for reciprocating the piston in the fluid housing to cause fluid to be pulled in and out of the fluid directing tool. A method of using the reciprocating pump is also disclosed. The pump is placed in to the wellbore in an area where fluid is desired to be pumped out of the wellbore. Once positioned in the wellbore, the pump is operated to remove fluid from the wellbore.

What is claimed is: 
     
         1 . A reciprocating downhole pump for use in a wellbore, the pump comprising:
 a fluid directing apparatus for directing fluid in and out of the pump, the fluid directing apparatus having an inlet disposed in a sidewall of the fluid directing apparatus and an outlet;   a piston disposed in a fluid housing; and   a piston driving apparatus for reciprocating the piston in the fluid housing to cause fluid to be pulled in and out of the fluid directing tool.   
     
     
         2 . The pump of  claim 1  wherein the piston driving apparatus is a continuous self reversing screw disposed in a housing that can be designed to provide a specific length of travel and reciprocation rate of the piston, the screw having a downward directing channel and an upward directing channel disposed thereon. 
     
     
         3 . The pump of  claim 2  wherein the piston driving apparatus is operated by a hydraulic drive disposed downhole or at a surface of the wellbore, the hydraulic drive can be an electric motor, a hydraulic motor or a triplex pump. 
     
     
         4 . The pump of  claim 1  wherein the piston is driven by a hydraulic piston driving apparatus. 
     
     
         5 . The pump of  claim 4  wherein the hydraulic piston driving apparatus comprises:
 a hydraulic piston apparatus disposed in a primary housing and connected to the piston via a rod, the hydraulic piston apparatus having a piston head and a rod element extending therefrom; and 
 a hydraulic fluid driving apparatus for forcing fluid in two directions through the hydraulic piston driving apparatus to force the hydraulic piston apparatus in the uphole and downhole directions. 
 
     
     
         6 . The pump of  claim 5  further comprising:
 a first separation element that separates the fluid housing from the primary housing of the hydraulic piston driving apparatus, the first separation element having a passageway disposed therein to permit the rod to slide therein; and 
 a second separation element that separates the primary fluid housing from a secondary fluid housing of the hydraulic piston driving apparatus, the second separation element having a first passageway disposed therein to permit the rod element of the hydraulic piston apparatus to slide therein. 
 
     
     
         7 . The pump of  claim 6  wherein the second separation element further includes a second passageway disposed therein to permit hydraulic fluid to be pumped therethrough. 
     
     
         8 . The pump of  claim 7  wherein the hydraulic piston driving apparatus further includes a conduit disposed in the secondary fluid housing to direct hydraulic fluid from the hydraulic fluid directing apparatus into the second passageway disposed in the second separation element to permit hydraulic fluid to flow into the primary fluid housing between the piston head and the second separation element. 
     
     
         9 . The pump of  claim 8  wherein the piston head has a passageway disposed therein in fluid communication with another passageway disposed in the rod element of the piston head to permit fluid to flow from the secondary fluid housing to the primary fluid housing between the piston head and the first separation element. 
     
     
         10 . The pump of  claim 2  wherein the pump further comprises:
 a sleeve slidably disposed within the housing and around the screw, the sleeve has at least one radially directed opening disposed in a lower end of the sleeve; and 
 a blade supported by the sleeve to engage the upward directing channel and the downward directing channel. 
 
     
     
         11 . The pump of  claim 10  wherein the pump further comprises a dog that is attached to the blade and is rotatably disposed within the radially directed opening in the sleeve. 
     
     
         12 . The pump of  claim 3  further comprising an electric drive having variable frequencies to vary the speed at which the hydraulic drives operate the piston driving apparatus. 
     
     
         13 . A method, the method comprising:
 placing a pump into a wellbore in an area where fluid is desired to be pumped out of the wellbore, the pump comprising:
 a fluid directing apparatus for directing fluid in and out of the pump, the fluid directing apparatus having an inlet disposed in a sidewall of the fluid directing apparatus and an outlet; 
 a piston disposed in a fluid housing; and 
 a piston driving apparatus for reciprocating the piston in the fluid housing to cause fluid to be pulled in and out of the fluid directing tool; and 
   operating the pump to remove fluid from the wellbore.   
     
     
         14 . The method of  claim 13  wherein the piston driving apparatus is a self reversing continuous screw that can be designed to provide a specific length of travel and reciprocation rate of the piston, the screw having a downward directing channel and an upward directing channel disposed thereon. 
     
     
         15 . The method of  claim 14  wherein the piston driving apparatus is operated by a hydraulic drive disposed downhole or at a surface of the wellbore, the hydraulic drive can be an electric motor, a hydraulic motor or a triplex pump. 
     
     
         16 . The method of  claim 13  wherein the piston is driven by a hydraulic piston driving apparatus. 
     
     
         17 . The method of  claim 16  wherein the hydraulic piston driving apparatus comprises:
 a hydraulic piston apparatus disposed in a primary housing and connected to the piston via a rod, the hydraulic piston apparatus having a piston head and a rod element extending therefrom; and 
 a hydraulic fluid driving apparatus for forcing fluid in two directions through the hydraulic piston driving apparatus to force the hydraulic piston apparatus in the uphole and downhole directions. 
 
     
     
         18 . The method of  claim 17  further comprising:
 a first separation element that separates the fluid housing from the primary housing of the hydraulic piston driving apparatus, the first separation element having a passageway disposed therein to permit the rod to slide therein; and 
 a second separation element that separates the primary fluid housing from a secondary fluid housing of the hydraulic piston driving apparatus, the second separation element having a first passageway disposed therein to permit the rod element of the hydraulic piston apparatus to slide therein. 
 
     
     
         19 . The method of  claim 18  wherein the second separation element further includes a second passageway disposed therein to permit hydraulic fluid to be pumped therethrough. 
     
     
         20 . The method of  claim 19  wherein the hydraulic piston driving apparatus further includes a conduit disposed in the secondary fluid housing to direct hydraulic fluid from the hydraulic fluid directing apparatus into the second passageway disposed in the second separation element to permit hydraulic fluid to flow into the primary fluid housing between the piston head and the second separation element. 
     
     
         21 . The method of  claim 20  wherein the piston head has a passageway disposed therein in fluid communication with another passageway disposed in the rod element of the piston head to permit fluid to flow from the secondary fluid housing to the primary fluid housing between the piston head and the first separation element. 
     
     
         22 . The method of  claim 14  wherein the pump further comprises:
 a sleeve slidably disposed within the housing and around the screw, the sleeve has at least one radially directed opening disposed in a lower end of the sleeve; and 
 a blade supported by the sleeve to engage the upward directing channel and the downward directing channel. 
 
     
     
         23 . The method of  claim 22  wherein the pump further comprises a dog that is attached to the blade and is rotatably disposed within the radially directed opening in the sleeve. 
     
     
         24 . The method of  claim 15  further comprising an electric drive having variable frequencies to vary the speed at which the hydraulic drives operate the piston driving apparatus.