This invention relates generally to oilfield equipment, and more particularly, but not by way of limitation, to an improved base system for supporting a beam pumping unit.
Hydrocarbons are often produced from well bores by reciprocating downhole pumps that are driven from the surface by pumping units. A pumping unit is connected to its downhole pump by a rod string. Although several types of pumping units for reciprocating rod strings are known in the art, walking beam style pumps enjoy predominant use due to their simplicity and low maintenance requirements.
In most walking beam pumping units, the walking beam is pivotally supported atop a Samson post through a saddle bearing assembly. Typically, the Samson post includes a front leg and a rear leg that are secured to one another by a connection bracket below the saddle bearing assembly. The distal end of the front leg is secured to a base assembly of the pumping unit, often with a bolted connection. The distal end of the rear leg can be secured to the pedestal or to the base assembly of the pumping unit with large bolts. The Samson post carries a significant amount of weight and is exposed to lateral forces during the operation of the pumping unit. The base assembly also carries the weight of the sub base (or pedestal) and the gearbox, crank arms and other components supported by the pedestal.
In the past, the base assembly has been shipped to the well site and placed onto a concrete pad. The base assembly typically includes a series of interconnected steel beams that are anchored to the concrete pad with bolts. The Samson post and pedestal are the connected to the top of the base assembly. Although widely adopted, the use of an independent base assembly presents added shipping and installation costs. There is, therefore, a need for an improved support system for a walking beam pumping unit. It is to these and other deficiencies in the prior art that embodiments of the present invention are directed.
In one aspect, a beam pumping unit includes an integrated base assembly that has a unitary pedestal, a Samson post supported by the integrated base assembly, and a gear box supported by the integrated base assembly. The beam pumping unit optionally includes a front connection plate and a pedestal connection plate.
In another aspect, the invention includes a modular foundation system for a beam pumping unit. The modular foundation system includes a pad, a plurality of embedded anchors within the pad and a modular sub base connected to the pad through the embedded anchors.
In yet another aspect, the invention provides a beam pumping unit that has an integrated base assembly a Samson post supported by the integrated base assembly, and a gear box supported by the integrated base assembly. In this embodiment, the integrated base assembly includes both a unitary pedestal and a unitary front riser
The weight and forces generated by the beam pumping unit 100 are supported by an integrated base assembly 114. The integrated base assembly 114 incorporates the base, the reducer sub base (pedestal) and the concrete pad of a traditional pumping unit into a single, unitary component (designated collectively as integrated base assembly 114). In exemplary embodiments, the integrated base assembly 114 is formed as a precast concrete body that is designed and configured to distribute and transfer the weight and dynamic loading forces produced by the beam pumping unit 100. The integrated base assembly 114 may be constructed using post-tensioning, pre-tensioning, simple rebar reinforcement or a combination of these concrete casting and reinforcing methods. In each case, the integrated base assembly 114 includes a series of interconnected or separated structural reinforcements that allow the pad to accommodate and withstand the cyclic tensile load forces that are produced by the beam pumping unit 100 during operation.
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Each crank arm 110 is pivotally connected to a pitman arm 124 by a crank pin bearing assembly 126. The two pitman arms 124 are connected to an equalizer bar 128, and the equalizer bar 128 is pivotally connected to the rear end of the walking beam 120 by an equalizer bearing assembly 130. A horse head 132 with an arcuate forward face 134 is mounted to the forward end of the walking beam 120. The face 134 of the horse head 132 interfaces with a flexible wire rope bridle 136. At its lower end, the bridle 136 terminates with a carrier bar 138, upon which a polished rod 140 is suspended.
The polished rod 140 extends through a packing gland or stuffing box 142 on a wellhead 144. A rod string 146 of sucker rods hangs from the polished rod 140 within a tubing string 148 located within the well casing 150. The rod string is connected to the plunger of a subsurface pump (not illustrated). In a reciprocating cycle of the beam pumping unit 100, well fluids are lifted within the tubing string 148 during the rod string 146 upstroke.
The Samson post 118 includes a front leg 152, a rear leg 154 and a connection bracket 156. In some embodiments, the connection bracket 156 is rigidly affixed to an upper end 158 of the front leg 152. The connection bracket 156 can be secured to the front leg 152 with a welded or bolted connection. A lower end 160 of the front leg 152 is rigidly secured with a bolted connection to the integrated base assembly 114 with a front connection plate 162. In this way, the front leg 152 and connection bracket 156 are held in a fixed geometric relationship with the integrated base assembly 114. The rear leg 154 includes a proximal end that is retained by the connection bracket 156. The rear leg 154 includes a distal end that terminates in a rear foot 164. The rear foot 164 is attached to the distal end of the rear leg 154 at a fixed angle with a welded or bolted connection.
The rear foot 164 and gearbox 106 are secured to the pedestal 116 with a pedestal connection plate 166. The integrated base assembly 114 optionally includes a rear connection plate 168. The rear connection plate 168 can be used to support the prime mover 102 and other drive elements between the prime mover 102 and the gearbox 106.
The front connection plate 162, the pedestal connection plate 166 and the rear connection plate 168 are each constructed as rigid, durable, high-strength metal frames that are partially embedded within the integrated base assembly 114 as it is formed. In this way, the front connection plate 162, the pedestal connection plate 166 and the rear connection plate 168 are produced as integral parts of the integrated base assembly 114. The embedded portions of the front connection plate 162, the pedestal connection plate 166 and the rear connection plate 168 are optimally connected to the internal structural reinforcements within the integrated base assembly 114.
During manufacture, the structural reinforcements are assembled and placed into a concrete form (not shown). The front connection plate 162, the pedestal connection plate 166 and the rear connection plate 168 are then connected to the structural reinforcements such that the exposed portions of the front connection plate 162, the pedestal connection plate 166 and the rear connection plate 168 extend above or beyond the concrete form. Next, an appropriate, high-strength concrete mixture is poured into the form to cover the embedded portions of the front connection plate 162, the pedestal connection plate 166 and the rear connection plate 168. Depending on the type of structural reinforcements used and whether the integrated base assembly 114 is pre-tensioned or post-tensioned, additional steps may be required to complete the production of the integrated base assembly 114. When fully and properly tensioned, the integrated base assembly 114 can be shipped to the well site and placed on a leveled landing surface. The Samson post 118, gearbox 106 and other components of the pumping jack 100 can then be secured to the exposed portions of the integrated base assembly 114.
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Thus, the various embodiments of the integrated base assembly 114 disclosed herein present an efficient, cost-effective solution for supporting the beam pumping unit 100. It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and functions of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. It will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other systems without departing from the scope and spirit of the present invention.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/547,572 entitled “Integrated Base Assembly for Pump Jack,” filed Aug. 18, 2017, the entire disclosure of which is herein incorporated by reference.
Number | Date | Country | |
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62547572 | Aug 2017 | US |