Page 41 - Petroleum and Gas Field Processing

aspects of the field are tied together and considered as one production
system. The main objective of that system is to obtain maximum recovery
in the most economical and safe manner.
In the following subsections, the functions are operations related to
subsurface production engineering are briefly described.

1.8.1 Well Completion Design

The well completion is the subsurface mechanical configuration of the well
which provides the passage for the produced fluids from the face of the
formation to the wellhead at the surface. The well completion design is
needed by the drilling engineers to properly design, plan, and execute the
drilling of the well that is compatible with the well completion.
Types of Well Completion

There are three major types of well completion:
1. Open Hole Completions: For this type of completion, the well is
drilled down to a depth that is just above the target petroleum
formation. The production casing is then lowered into the well and
cemented. The target formation is then drilled and is left uncased
(open). Depending on the production rate and the properties of the
produced fluids, the well may be produced through the production
casing or through production tubing placed above the producing
formation with a packer that provides a seal between the tubing
and casing. One of the functions of the packer is to protect the
casing from the produced fluids. Figure 11 illustrates this type of
well completion.
2. Cased Hole (Perforated) Completions: For this type of completion,
the well is drilled all the way through the producing zone and the
production casing is lowered and cemented. The casing is then
perforated across the producing zone to establish communication
between the formation and the well, as illustrated in Figure 12.
Again, depending on the producing conditions, production could
be either through the casing or through a tubing.
3. Liner Completion: As illustrated in Figure 13, the production casing
is set and cemented above the petroleum formation similar to an
open hole completion. A liner (basically a smaller diameter casing)
is then set and cemented across the producing formation. The linear
is then perforated to establish communication between the well and
the formation. In some cases, an already perforated (or slotted)
liner may be set across the formation without cementing.

Copyright 2003 by Marcel Dekker, Inc. All Rights Reserved.