Page 54 - Petroleum and Gas Field Processing

6. Plug and Abandonment. For abandoning depleted wells, cement is
used to squeeze and seal off all perforations and to set several
cement plugs in the well.

1.8.4 Producing the Well
Producing the well means bringing the fluids that flowed from the
formation into the borehole, from the bottom of the well to the surface.
Fluids need to be brought to the surface at the desired rate and with
sufficient pressure to flow through the surface-treating facilities. Some
reservoirs possess such a high pressure that it can produce the desired rates
at high bottom-hole pressures that could push the fluids to the surface at
the desired wellhead pressure. This mode of production is known as
natural flow. Reservoirs with high initial pressures and with strong
pressure support (i.e., from bottom water) can be produced under natural
flow for extended period of time.
When the reservoir pressure declines, pressure support may be
provided by injecting water or gas into the reservoir to maintain natural
flow at desired rates and surface pressures. In some cases, however,
pressure support may not be sufficient to maintain desired natural flow.
This usually occurs due to increased water production, which increases the
hydrostatic head and friction losses in the tubing. Therefore, the fluids
may reach the surface at lower than desired pressures, or may not even
reach the surface. In such cases, external means of lifting the fluids to the
surface will be needed. These means are known as the artificial lift
methods. Production engineers are responsible for selecting, designing,
installing, and operating artificial lifting facilities.

Artificial Lift Methods

The objective of artificial lift is to create low bottom-hole pressure to allow
high rates of production from the formation into the bottom of the well
and artificially lift the fluids to the surface with the desired surface
pressure. The main methods of artificial lift are as follows:
1. Sucker Rod Pumping (SRP): This is the oldest and most
common method of artificial lift used in the industry. The
method is, however, limited to vertical and straight wells with
relatively low productivity. The pumping facility consists mainly
of surface equipment that provide reciprocating up-and-down
movement to a rod string (the sucker rod) that is connected to

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