System and method for direct drive pump

Abstract

A method and a system are provided for a direct drive pump for use in pumping fluids and/or quasi-fluids from one location to another. In the direct drive pump, bearings or bushings are optimally spaced, taking into account various operational considerations such as load, path, pressure, and tension. Further, bearings or bushings are coupled to the drive string, thus assisting in more efficient installation and de-installation. The bearings or bushings are not fixed to the production casing or drive tube. In embodiments, the drive tube can be vented, and the production fluid can be used as a lubricant for the system bearings.

What is claimed is: 
     
         1 . A direct drive pump system, comprising:
 a well casing, the well casing being a housing for the direct drive pump system;   a pump having a pump inlet situated at a lower end of the well casing;   a production tubing;   a drive string rod, the drive string rod being situated within the production tubing;   at least one of a stabilizer and a bearing, the at least one of a stabilizer and a bearing being disposed on the drive string rod and serving as support for the drive string rod to ensure stable rotation during operation of the pump;   wherein the pump situated downhole in the well casing drives the drive string rod to rotate to encourage well fluid pressurized from the pump to flow uphole towards the surface for production.   
     
     
         2 . The pump system of  claim 1 , wherein the at least one of a stabilizer and a bearing is closely spaced along the entire length of the drive string rod to ensure stable rotation during operation of the drive string rod. 
     
     
         3 . The pump system of  claim 2 , wherein the at least one of a stabilizer and a bearing is at least one of a bearing assembly, a bushing, a bearing mounted in a housing, a bearing mounted in a plastic housing, a ceramic-polymer alloy bearing, a ceramic bushing, a non-corrosive bearing, and a ceramic bearing. 
     
     
         4 . The pump system of  claim 2 , wherein the fluid flow passes around an outer surface of the production tubing. 
     
     
         5 . The pump system of  claim 2 , comprising:
 a drive tube, the drive tube being situated within the production tubing; and   at least one centralizer,   wherein the at least one centralizer is associated with the drive tube and supports the drive tube so that the drive tube remains fairly centered in the production tubing, and the drive string rod and its stabilizers are situated within the drive tube.   
     
     
         6 . The pump system of  claim 2 , wherein the fluid flow passes around an outer surface of the drive tube. 
     
     
         7 . The pump system of  claim 1 , further comprising a pressure regulator situated between a well pump and a production flow line,
 wherein the pressure regulator opens when the pressure differential between the drive tube and the production tubing exceeds a predetermined set value.   
     
     
         8 . The pump of  claim 1 , further comprising a motor to drive the pump in order to drive the drive string rod, wherein the motor is an electric motor which effectively drives the rod string at one of: a low RPM with speed increasing capability gearing, and about 3500 RPM pump operational speed. 
     
     
         9 . The pump of  claim 1 , wherein the pump provides a high volume artificial lift system of well fluid. 
     
     
         10 . A method for installing a direct drive pump in a well, comprising:
 coupling a bottom hole assembly to a first length of production tubing;   lowering the bottom hole assembly and the first length of production tubing into a well;   securing the production tubing in a wellhead;   coupling an additional length of production tubing to the first length of production tubing;   lowering the additional length of production tubing into the well;   lowering a first length of drive tube down inside the production tubing lengths;   securing the first length of drive tube to the wellhead;   coupling an additional length of drive tube to the first length of drive tube;   lowering the additional length of drive tube inside the production tubing lengths;   lowering a first length of at least one drive rod down inside the drive tube, the at least one drive rod having at least one stabilizer for supporting the drive rod in the respective length of drive tube;   coupling an additional length of at least one drive rod to the first length of at least one drive rod;   lowering the additional length of at least one drive rod down inside the drive tube; and   attaching a drive head to the production tubing, drive tube, and drive rods such that the lengths of drive rods can be turned by a motor to drive the pump in the bottom hole assembly.   
     
     
         11 . The method of  claim 10 , wherein more lengths of production tubing are attached in succession to the additional length of production tubing until a desired depth by the bottom hole assembly is reached in the well and the lengths of production tubing are secured to the wellhead,
 more lengths of drive tube are attached in succession to the additional length of drive tube until a desired depth is reached in the well and the lengths of the drive tube are secured to the wellhead, and   more lengths of at least one drive rod are attached in succession to the additional length of at least one drive rod until a desired depth is reached in the well, and the lengths of the at least one drive rod are supported by stabilizers in the drive tube.   
     
     
         12 . The method of  claim 11 , wherein the bottom hole assembly includes a multi-stage pump, a thrust bearing, a drive rod, and a drive tube receiver. 
     
     
         13 . The method of  claim 12 , wherein at least one of at least two lengths of the drive tube, at least two lengths of production tubing, and at least two lengths of drive rods are mated by a threaded connection. 
     
     
         14 . The method of  claim 13 , wherein each respective length is two 30 feet segments, the two segments being coupled together and lowered into the well as a single length. 
     
     
         15 . The method of  claim 14 , wherein the length of drive rod string includes a splined rod connector on one end and a stab-in receiver on the other end, so that when the splined rod connector of the first length of drive rod string meets the stab-in receiver of the additional length of drive rod string. 
     
     
         16 . The method of  claim 15 , wherein a surface flow line is attached to the wellhead. 
     
     
         17 . A method for installing a direct drive pump in a well, comprising:
 coupling a bottom hole assembly to a first length of production tubing;   lowering the bottom hole assembly and the first length of production tubing into a well;   securing the production tubing in a wellhead;   coupling an additional length of production tubing to the first length of production tubing;   lowering the additional length of production tubing into the well;   lowering a first length of at least one drive rod down inside the production tubing, the at least one drive rod having at least one stabilizer for supporting the drive rod in the respective length of production tubing;   coupling an additional length of at least one drive rod to the first length of at least one drive rod;   lowering the additional length of at least one drive rod down inside the production tubing; and   attaching a drive head to the production tubing and drive rods such that the lengths of drive rods can be turned by a motor to drive the pump in the bottom hole assembly.