Introduction to AutographPC Sizing and Simulation Software

Baker Hughes Centrilift AutographPC ™ is an artificial lift and application simulation software. It’s a powerful tool to give a comprehensive and user-friendly system design. This software can be used to design production systems, including: electrical submersible pumping (ESP) systems; electrical submersible progressing cavity pumping (ESPCP™) systems; rod-driven progressing cavity pumping (RDPCP™) systems; horizontal surface pumping (HPump™) systems; and gas lift systems, etc.

Each system installation is unique and with this software, all the well information, including production characteristics, fluid properties and well conditions, can be entered during the initial design phase to produce the optimum solution for each sizing.

Once installed and launched, Design Modes Screen, shown in the following screenshot, appears. Design Modes screen has been added to AutographPC since July 12, 2017. This is the screen where the user can select a design mode and start a new sizing program.

 

 

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Back Pressure Regulators for Gassy Sucker Rod Lifted Wells

The problem of heading (flow off and pump) is often encountered in gassy wells. This heading effect which can blow the tubing dry occurs as follows:

  • Gas expansion in the tubing as oil from the reservoir travels towards the surface (due to gas pressure decrease).
  • Formation of a gas “plunger” that can push the liquid above it out of the tubing and into the flow line at high speed. As the gas forces the liquids out of the tubing, the pressure in the tubing decreases rapidly and the gas expands even more.
  • This heading behavior of reservoir fluids causes cycles of high production followed by low or no production.

When heading process starts, the expanding gas pushes the liquid into the flowlines and increases production for a short time. In the meantime, the liquid leaving the tubing is replaced by more and more free gas. Eventually, the tubing is blown dry and production stops until the tubing fills with liquid again.

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Pressure loss calculations through a conduit

Whenever a fluid flows through a conduit pressure loss occurs. Many methods are available to calculate frictional pressure losses. They range from simple empirical equations to rigorous mechanistic multiphase flow models.

Darcy-Weisbach flow equation:

The Darcy-Weisbach flow equation is theoretically sound equation derived from the Conservation of Mass and Conservation of Momentum laws. Named after Henry Darcy and Julius Weisbach, it relates the pressure loss due to friction along a given length of pipe to the average velocity of the fluid flow for an incompressible fluid.

The Darcy-Weisbach equation contains a dimensionless friction factor, known as the Darcy friction factor. This is also variously called the Darcy–Weisbach friction factor, friction factor, resistance coefficient, flow coefficient, or Moody friction factor.

In a cylindrical pipe of uniform hydraulic diameter d, flowing full, the pressure loss due to density and viscous effects dp/dL is proportional to length L and can be characterized by the Darcy–Weisbach equation:

Where:

  • dP/dL = Pressure Gradient (psi/ft)
  • f = friction factor
  • ρ = Fluid density (lb/ft3)
  • v = Fluid velocity (ft/s))
  • d = Hydraulic diameter (ft))

The equation can be written as shown below in both typical US oilfield units and SI units:

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Advantages & Disadvantages of Jet Pumps in Oil Well Applications

This article will present the typical ranges of jet pump operating parameters and discusses the advantages and disadvantages of jet pumps in oil wells applications.

Jet Pump Operating Envelope:

Advantages and disadvantages of jet pumps:

  • Advantages:

Jet pumps have several advantages such as:

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How Does Jet Pump Work?

The jet pump operates by pumping power fluid at high pressure and rate from surface to activate/drive a downhole pump. Looking at the downhole jet pump, there are three main components:

  • Nozzle,
  • Throat,
  • And Diffuser.

The nozzle and throat are the key components of a jet pump. The ratio of the areas of these two parts is known as the area ratio of the pump and it determines the performance characteristics of the pump. Pumps with the same area ratio have the same performance and efficiency curves

Jet Pumps operates on Venturi principle. Above the JP, before entering the nozzle, the power fluid has high pressure (designated as PN) and low flow velocity.

While the power fluid passes the nozzle, due to the decrease in flow area it is transformed from low velocity, high static pressure flow to a high velocity, low static pressure flow (PS). This creates a pressure drop below the nozzle which drives the reservoir fluids into the pump.

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