Back-Pressure Valve installed in tubing hangers

A back-pressure valve is a type of check valve, typically installed in the tubing hanger, to isolate the production tubing. The back-pressure valve is designed to hold pressure from below yet enable fluids to be pumped from above, as may be required for well-control purposes. Thus, it reduces downtime and operating cost by allowing for repairs without killing the well.

BPV is commonly used during the nipple down and up of the drilling BOP stack, nipple up or down of Christmass trees, test the Christmas tree (2-way check valve), and during the replacement of the master valve.

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Beam Pump Artificial Lift Optimization

This article gives you some good practices and rules of thumb for optimizing beam pump applications. The following topics have been presented:

  • Artificial Lift Optimization – What does it mean?
  • Required information
  • Typical design situations
  • Optimization considerations
  • Simulate / Measure initial conditions
  • Pump condition, structure loading, and gearbox Loading
  • Miscellaneous notes
  • Design Guidelines: Pump Efficiency, Structure Loading, Gearbox Loading
  • Case 1: Increase Capacity
  • Case 2: Size unit for well w/no unit
  • Dialing in your design
  • Unit Sizing “Rules of Thumb”
  • Sucker Rod Design
  • Rod Guides: Snap Ons, Molded Guides

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Why Do We Counterbalance Sucker Rod Pumping Units?

A good understanding of counterbalance is vital to the successful operation of surface sucker rod pumping units.  Poor counterbalance practices can cause early failure of the gear reducer gearing and will result in excessive energy cost.

Non-counterbalanced lever system:

The up-stroke:

The figure above represents a simple non-counterbalanced lever system. On the up-stroke, by pulling down on the end of a beam, a man is lifting a bucket full of water having a combined weight of 150 lbs.

Note that the upstroke effort of the man is a substantial 150 lbs.

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The difference between Conventional & Mark II Pumping Units

This article helps understand the difference between Conventional & Mark II pumping units in term of production performance. SROD, the predictive program from General Electric (GE), has been used in order to compare the Reducer Torque Performance,  the Stroke Length, and the Polished Rod Velocity, of a conventional unit and a Mark II unit. In order to do that, production data from the well MF-1 are used.

MF-1 is an oil well activated using a sucker rod pump. The target rate is 500 BPD, the pump is set at 6000 ft, the plunger diameter is 1.5 inch, the rod string is 86, the stroke length is 144 inch and the pumping speed is 13 spm.

Reducer Torque:

  • Reducer Torque vs. Crank Angle:

SROD, the predictive program from GE, has been used in order to compare the reducer torque performance of a conventional unit and a Mark II unit. The plots “Torque (in in-lbs) versus the crank angle” are depicted in the following graph.

Note that the MKII does a better job approaching the uniform torque goal than the conventional unit and therefore has lower peak torque.

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API Subsurface Pump Designation

The pump designation is part of API Spec 11AX and describes the main specifications of an API subsurface pump. It is a nomenclature to classify API sucker rod pumps and tubing pumps according to their main characteristics. It is comprised of seven parts, separated by dashes.
Example: 20-125-RHBC-10-4-2-2

Each part, in order, describes the following specifications:

  • Nominal tubing size (inch – given as a key representing the actual size)
  • Basic bore size (inch)
  • Type of pumptype of barrellocation and type of seating assembly (letter code)
  • Barrel length (ft)
  • Plunger length (ft)
  • Length of upper extension, used with heavy-wall barrel (inch)
  • Length of lower extension, used with heavy-wall barrel (inch)

 

Example: A 1 1⁄4 in. (31.8 mm) bore rod type pump with a 10 ft (3.048 m) heavy wall barrel and 2 ft (0.610 m) upper extension, 2ft (0.610 m) lower extension, a 4 ft (1.219 m) plunger, and a bottom cup type seating assembly for operation in 2 3⁄8 in. (60.3 mm) tubing, would be designated as follows:

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