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1

Potential Environmental Impact from Mishandled Waxy Crude Oils

JR Becker, BJ Unichem Chemical Services

ABSTRACT
Pipeline failures can occur in for a variety of reasons, including, but not limited to, corrosion, scale, and wax obstruction.
Because failures are extremely costly and potentially disastrous to the environment, producers, transporters, and refiners often expend
considerable amounts of capital toward their prevention. In addition to construction costs incurred by building high quality transport
facilities, enormous financial resources are spent regularly on chemical treatments. Generally speaking producers, transporters, and
refiners are little concerned with the preceeding or subsequent costs of the oil handling process. Consequently, each does only that
which is absolutely required to move the product along its way to the consumer, nothing more. Although pipeline failures are rare,
they do occur, and the appropriate chemical treatment can assure safer pipeline operation. If the producer would effectively treat the
oil prior to transferring it to the transporter and refiner, he would reap considerable economic benefit. The following paper discusses
paraffin wax obstruction and presents field and laboratory data supporting the above conclusion.

INTRODUCTION
Adam Smith wrote,Every individual endeavors to employ his capital so that its produce may be of greatest value. He
generally neither intends to promote the public interest, nor knows how much he is promoting it. He intends only his own security
only his own gain. And he is in this led by an INVISIBLE HAND to promote an end which was no part of his intention. By pursuing
his own interest he frequently promotes that of society more effectually than when he really intends to promote it.(1). This statement
could be used to characterize most industry throughout all of history, and is particularly applicable to the oil industry throughout most
of its existence.

In the early days of oil production the principle product was kerosene, which was used for heating and illumination. The by-
products of production were thought to be of little use, and as a result, large pools of heavy crude oil began to accumulate around
refinery locations. Fortunately, prior to Edwin Laurentine Drakes 1859 discovery of oil near Titusville, Pennsylvania, a professor of
chemistry at Yale University, Benjamin H. Silliman, Jr., had conducted a scientific study of crude oil. This study, which was
commissioned by Pennsylvania Rock Oil Company, owned by George H. Bissell and Jonathan G. Eveleth, resulted in the realization
that the crude oil was more valuable than previously thought. Silliman reported, your company has in its possession a raw material
from which, by a simple and not expensive process, t they may manufacture very valuable products(2). Despite the results of this
study, more than seven decades passed before serious efforts took place to maximize the potential of this amazingly rich resource.
Throughout the period 1855-1930, little attention was paid to the immense environmental impact of crude oil production,
transportation, and refining. Fields were developed, overproduced, and abandoned, pipelines used and discarded, and refineries were
operated and abandoned once the local oil played out. Periods of boom and bust were the norm and still society benefited in the short
term. Since 1855 more than 100 useful raw materials, used to produce literally millions of products common to everyday life in
modern society, have been extracted from crude oil. Despite the motivation of security and gain, oil companies have enriched the lives
of all of us in some way or another.

The best figures available (3) indicate that around 500,000 to 550,000 miles of pipeline are operated by more than 264 liquids
and natural gas companies required to report to the U.S. Federal Energy Regulatory Commission (FERC). U.S. oil consumption has
grown from 16,950,000 barrels a day to over 19,000,000 barrels a day over the period 1994 to the present. These are extremely
impressive statistics, but the relatively infrequent occurrence of pipeline failure is even more impressive. When a failure does occur,
the costs incurred are enormous both in terms of monetary fines and ecological damage. In the following sections of this paper we
will examine some of the reasons for crude oil transport failures, and discuss some of the remedies that may be applied.

BACKGROUND

Crude oils are enormously complex conglomerates of vast numbers of chemical components. These components range from
simple hydrocarbons to complex heteroatomic organometallic compounds. This complexity is reflected by the ubiquitous array of
products that are derived from the refining of crude oil i.e., plastics, paint, tires, fibers, ink, detergents, gasoline, hand cream, shampoo,
floor coverings, motor oil, etc.

When crude oil is removed from oil-containing formations, it is very often accompanied by water that has been emulsified by
natural surfactants contained by the oil. This water also contains a rich assortment of anions and cations that combine under the
changing conditions of the reservoir to produce scale (e.g., calcium carbonate, calcium sulfate, and barium sulfate). Water also
combines with acids, bases, sulfur, fatty acids, and soluble salts to produce extremely corrosive environments. In addition to these
inorganic materials, the hydrocarbon phases contain asphaltene and waxy components that are sparingly soluble under conditions of
changing temperature and pressure. This dynamic environment leads to a large variety of potential problems that include corrosion,
inorganic scale formation, asphaltene precipitation, and wax deposition. Corrosion and scale rank very high as causes of pipeline
failures. In fact, they are only second in ranking to mechanical failures. Interestingly, because corrosion and inorganic scale
formation rank so high in causes of failures, they are generally anticipated and treated for prior to the introduction oil to the pipeline
system. These measures are undertaken to avoid the potential damage that can result from the presence of these materials, but often
unexpected benefits are derived (e.g., increased production and lower operating costs). Although organic deposits (e.g., wax and
asphaltene) are seldom as destructive as either corrosion or scale, they are less frequently treated for and are often handed off to the
next link in the crude oils chain of possession. It is these organic obstructions and particularly wax obstructions that will be the focus
of this paper.

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DISCUSSION

Problem paraffin waxes found in crude oil systems consist mainly of linear saturated carbon chain molecules (e.g., C
n
H
2n+2
).
These molecules tend to form highly ordered multi-molecular aggregates held together through forces of induction (London forces of
attraction). The formation of these multi-molecular aggregates is favored by temperature declines where threshold energies of
molecular collisions are of sufficient but not excessive force for inter-molecular combination. Therefore, highly ordered crystal
structures begin to form as the temperature of the crude oil mixture declines. Waxes accumulate as obstructions to the normal flow of
crude oil systems. The aggregates thus formed interact mechanically, and accumulate in constricted flow regions, pipe surfaces, and
quiescent storage areas. These accumulations can act as collection sites for inorganic scale and water, thereby providing an excellent
environment for combined corrosion and continued inorganic obstruction. Once it has been determined that paraffin wax
accumulation has restricted the normal production, transport, and/or storage of crude oil, measures should be quickly undertaken to
remedy the problem.

Production companies utilize surprisingly little paraffin wax control chemical even though its use has been proven to
increase the production life of many systems. When the stakes are high, as in offshore production, the incorporation of paraffin
treatments into field operations is not even questioned. However, in smaller producing wells where chemical expenditures are
carefully controlled, paraffin chemicals are seldom used. Most production companies would rather spend money on remediation
methods rather than on prevention.

Several remediation methods are available, among which include, hot oiling, hot watering, combination hot water and
surfactants, solvent, solvent-surfactant treatments, bacterial treatments, and crystal modifiers. Each method possesses strengths and
weaknesses. Hot oiling and