Page 267 - Petroleum and Gas Field Processing

needs. This requires superimposing the fractionation facilities to the gas
field processing scheme.
Most important in the design of a system for gas field processing, the
following parameters should be evaluated and considered in the study:
1. Estimated gas reserve (both associated and free)
2. The gas flow rate and composition of the feed gas
3. Market demand, both local and export, for the products
4. Geographic location and methods of shipping of finished
products
5. Environmental factors
6. Risks involved in implementing the project and its economics

Of these factors, the gas/oil reserve might be the paramount factor. Several
schemes can be recommended for field processing and separation of
natural gas, but the specific solution is found to be a function of the
composition of the gas stream, the location of this source, and the markets
available for the products obtained.

10.2 BACKGROUND
10.2.1 What Is Natural Gas?
Natural gas is the gas obtained from natural underground reservoirs either
as free gas or gas associated with crude oil. It generally contains large
amounts of methane (CH 4 ) along with decreasing amounts of other
hydrocarbons. Impurities such as H 2 S, N 2 , and CO 2 are often found with
the gas. It also generally comes saturated with water vapor. Other
information on natural gas and its usage under different commercial
products are found in Table 1 in the Introduction.

10.2.2 Why Field Processing?
The principal market for natural gas is achieved via transmission lines,
which distribute it to different consuming centers, such as industrial,
commercial, and domestic.
Field processing operations are thus enforced to treat the natural gas
in order to meet the requirements and specifications set by the gas
transmission companies. The main objective is to simply obtain the natural
gas as a main product free from impurities. In addition, it should be
recognized that field processing units are economically justified by the

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