Patent Application
20090194295
1. Technical Field
The present invention relates in general to gas separators for electrical submersible pumps and, in particular, to an improved system, method, and apparatus for integrating a gas separator into an electrical submersible pump assembly.
2. Description of the Related Art
A gas separator is used for separating the mixture of gas and liquid at the intake of a pump at the bottom of a well. Currently, gas separators are constructed in a separate housing that bolts to the bottom of the pump. The gas separator also acts as a fluid intake for the pump after the gas has been separated from the liquid stream.
For example, as shown in
Embodiments of a system, method, and apparatus for combining a centrifugal gas separator with a pump in an electrical submersible pump (ESP) assembly are disclosed. The invention uses an integral discharge connector to complete the assembly between the gas separator and pump. The base of the pump and discharge head of the gas separator are replaced with a connector that threads into the housing of the pump on one end and into the housing of the gas separator on the other end. The connector contains discharge ports for the discharge of the separated gas. The standard pump shaft is coupled to the standard gas separator shaft using a conventional coupling. The connector contains a bearing for shaft stabilization.
In one type of alternate embodiment, a single, longer pump shaft extends from the pump and is used by both the pump and the gas separator. This design eliminates the need for a stub shaft in the gas separator, and eliminates the shaft coupling.
In another alternate embodiment the gas separator is integrated into the pump housing. A conventional pump for an ESP assembly is converted to have an integral gas separator that requires little modification to the original pump. The pump is retrofitted to allow room for the gas separator internal parts. The pump is modified by removing the intale of the pump, and removing a sufficient number of pump stages to accommodate the gas separator components. A diverter tube is located in the pump housing and holes are drilled in the pump housing for retention pins to prevent rotation of the diverter tube. The pump housing also is modified to include gas exit ports. All of the gas separator components are located in the modified pump housing, and the original pump intake is attached at its original location. This design integrates the gas separator into the housing of the pump, eliminates all connections therebetween, and allows use of a single housing and shaft.
Advantages of this invention over current technology include the elimination of bolted connections, shorter installation lengths, reduced weight, fewer necessary components, and a reduction in overall product cost.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings.
So that the manner in which the features and advantages of the present invention are attained and can be understood in more detail, a more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings. However, the drawings illustrate only some embodiments of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
Referring to
As shown in
The pump 33 has a pump shaft 53, the centrifugal gas separator 37 has a gas separator shaft 55, and the pump shaft 53 is secured to the gas separator shaft 55 with a coupling 57. The coupling 57 may be located within the discharge connector 49 downstream from the diverter 47. The discharge connector 49 may contain a bearing 59 for stabilization of the pump shaft 53, the coupling 57 and the gas separator shaft 55.
In the embodiment shown, a downstream end 61 of the gas separator shaft 55 is located in the discharge connector 49. The diverter 47 has an inner diameter gas passage 63 in communication with the discharge ports 51 in the discharge connector 49. In addition, an outer diameter liquid passage 65 is located between an outer portion of the diverter 47 and an inner portion of the discharge connector 49. The diverter 47 may be located completely within an axial length of the discharge connector 49.
Another type of ESP assembly 71 is shown in the embodiment of
The centrifugal or rotary gas separator 37 provides active separation of the gas from the liquid. The fluid intake 41 is at the bottom of the separator 37. In one configuration, fluid is pushed up by the auger 43, separated by the rotor 45 and moved toward the pump 33. The separator 37 spins the heavier fluid to the outer diameter region 65 of the separator housing 39. The lighter fluid (e.g., gas) is conveyed through the inner diameter region 63 near the shaft 55, 75. The lighter fluid is then diverted by the diverter 47 out of the discharge ports 51 in the connector 49 that are located upstream from the first pump stage 36.
Referring now to
Thus, the centrifugal gas separator is located completely inside an axial length of the pump housing 83. The components of the separator may include an auger 95 and rotor 97 which are attached or otherwise coupled to the pump shaft 89 for rotation therewith. The pump intake 101 is located adjacent the upstream end 87 of the pump housing 83 upstream from the auger 95 and the rotor 97.
A diverter 99 is located between the rotor 97 and the pump stages 89. The diverter 99 is attached to the discharge ports 93 for discharging gas separated by the centrifugal gas separator through the wall of the pump housing 83. The diverter 99 has an inner diameter gas passage 103 in communication with the discharge ports 93. An outer diameter liquid passage 105 is located between an outer portion of the diverter 99 and an inner portion of the pump housing 83.
The diverter 99 may be mounted to the pump housing 83 (e.g., via pins inserted through holes formed in the pump housing 83) to prevent rotation of the diverter 99 relative to the pump housing 83. The pump shaft 89 extends out of the pump housing 83 beyond the upstream end 87 of the pump housing 83.
One embodiment of the invention also comprises a method of integrating a centrifugal gas separator and a pump. The method may comprise providing an electrical submersible pump (ESP) assembly having a pump with a pump housing, a pump shaft, a plurality of pump stages, and a pump intake; removing the pump intake from the pump housing; removing at least one of the pump stages from the pump housing to accommodate components of a centrifugal gas separator; installing the centrifugal gas separator in the pump housing; forming gas discharge ports in a wall of the pump housing in communication with a gas discharge from the centrifugal gas separator; and reinstalling the pump intake on the pump housing such that the centrifugal gas separator is located completely inside an axial length of the pump housing.
The pump intake may be defined at an original location for the pump intake on the pump housing, and then later securing the pump intake in the original location. The separator components may comprise a diverter, a rotor and an auger on the pump shaft, and then coupling the gas discharge ports in the wall of the pump housing with an inner diameter gas passage in the diverter.
In other embodiments, the diverter may be mounted to the pump housing to prevent rotation of the diverter relative to the pump housing, and the pump shaft may extend out of the pump housing beyond the upstream end of the pump housing. The diverter may be provided with an inner diameter gas passage in communication with the discharge ports, and an outer diameter liquid passage located between an outer portion of the diverter and an inner portion of the pump housing.
While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.
