Page 25 - Compression Machinery for Oil and Gas

Equipment Overview Chapter 2 15

broadest area of the range. Detailed information on each compressor type and
driver options can also be found in ***Chapters 3–7.

Types of Applications

There are a wide variety of different compression applications, typically
divided into three main categories: Upstream, Midstream, and Downstream.
Note that this section is just a brief summary of what types of equipment would
commonly be used in each application. Refer to Chapters 8–10 for more detail.

Upstream
1. Gas gathering application can typically utilize screw, rotary vane, recipro-
cating, and centrifugal compressors to collect gas at producing wellheads
and move the gas to a central location for processing and/or transport
through a series of various pipelines.
2. Export compression increases the pressure of processed gas to be suitable
for exporting from a processing facility to a pipeline for use by downstream
consumers. Typical compressors used are centrifugal and reciprocating.
3. Gas lift is a process where high-pressure gas is reinjected into the well riser
to mix with the fluid, thus helping with lifting oil from a well by making the
weight of the fluid column lighter in weight. This helps to maintain or
enhance production from a well. Both centrifugal and reciprocating can
be utilized in this process.
4. Gas reinjection can utilize centrifugal and reciprocating compressors to
maintain or enhance production in an oil reservoir that contains both oil
and gas. In this process the gas is injected into the reservoir to maintain pres-
sure and thus oil production rate.
5. Vapor recovery units—in vapor recovery, gas that separates from oil in a
storage system (tank or vessel) is recovered by removing the gas that col-
lects on the top of a vessel thus reducing the pressure within a storage tank
and capturing the gas for use elsewhere. Reciprocating, rotary screw, rotary
vane, or centrifugal compressors are typically employed as the compression
equipment for this application process.
6. Subsea compression equipment located in a subsea environment is used to
maintain reservoir production by reinjection into a well formation. Centrif-
ugal compressors with direct coupled high-speed motors are typically used
for this application.
7. Enhanced oil recovery (EOR) can include gas injection, water flood, and
chemical or steam injection. EOR is used to maintain reservoir pressure
by injection of gas either recycled from the reservoir itself or from an alter-
nate source using a different fluid like carbon dioxide (CO 2 ), nitrogen, or
other gas streams can be injected. Typical compression equipment used
can be reciprocating and centrifugal compression.