ABSTRACT
Despite its numerous benefits the search and production of crude oil
poses a lot of dangers to the environment. Among these include land,
water and air pollution. Prominent among the major sources of E&P
waste is drilling operations which form the second largest source of
waste after production activities. The major drilling wastes are drill
cuttings, drilling mud and obnoxious gas emissions. These wastes are
introduced into the environment through intentional as well as
accidental discharges and this expulsion into the environment has direct
and indirect effects on aquatic life, personnel working on the rig,
plants, flying birds, as well as the soil. This research work purposes
to identify the various forms of drilling waste, their effect on the
environment and to develop strategies in managing these waste
effectively. The ability to effectively identify, quantify, classify and
adopt strategies to eliminate or reduce the impact of drilling waste on
the environment defines an effective waste management practice. In all
situations source reduction of waste is the most favorable and
economically feasible drilling waste management option and should in all
cases be a priority over the other methods of waste management.
However, this task of adopting an effective waste management tactics is
not as simple as it looks. In its quest to developing effective
strategies for managing drilling waste, it is identified that the
quantity of waste generated plays an important role in drilling waste
management. It dictates the type of waste management method to adopt,
the design of waste boxes, waste disposal cost among others. A simple
user-friendly spreadsheet is therefore developed for waste volume
estimation. Again, a ten steps effective waste management procedure is
developed to serve as guidelines for drawing waste management plans.
Waste management plans should be updated regularly to capture changes in
regulations, new technologies and new operations. In conclusion it is
shown that the choice of the ideal drilling waste management is usually
dependent on the local regulations in place, technical efficiencies,
cost and the quantity of waste. The selection should always be therefore
subjected to effective environmental, economic and technical analysis.
As a result, a waste selection criterion has been developed which will
help eliminate some of the options that are not favorable.
CHAPTER ONE
FORMULATION OF PROBLEM
1.1 Problem Definition
Petroleum is among the world’s most important natural resources. It
is the most significant and highly traded primary commodity in the
international market (Illedare, et al., 1999) and has remained the
world’s primary source of energy for both industrial and domestic
applications since replacing coal early in this century. However, the
finding and production of petroleum involves the generation of drilling
waste which forms a major source of pollution in oil producing
environment. Almost every process in the finding and production of
petroleum generates wastes which impacts the environment negatively.
Until 1980’s, little or no thought was given to the generation and
disposal of cuttings and excess drilling fluids. Typically, these
materials were discharged overboard in offshore operations or buried
when drilling in land-based locations. The global environmental
awareness in the late 1980s to early 1990s made the oil and gas industry
and its regulators to understand and appreciate the potential
environmental impact of drilling waste (Geehan, et al, 2000).
In an effort to manage and reduce the impact of drilling waste on the
environment, a number of technologies and publications have been
written. Technologies such as directional drilling, slim-hole drilling,
coil-tubing drilling and pneumatic drilling are few of the drilling
practices that generates less amount of drilling waste. A number of
drilling waste management plans and programs have also been designed by
different companies and researchers. Drilling waste management refers to
ways by which drilling and associated wastes could be handled
effectively in order to minimize their effect on the environment. Wastes
that are usually associated with drilling operations are: - drill
cuttings, contaminated drilling fluids and additives, gaseous
contaminants from internal combustion engines, produced water as well as
heavy metals. The principal aim of waste management is to ensure that
waste does not contaminate the environment at such a rate or in such a
form or quantity as to overload natural assimilative processes.
Eliminating or minimizing waste generation is crucial, not only to
reduce environmental liabilities but also operational cost (Richards,
2007). The waste hierarchy is a common waste management technique that
has been reported in a number of literatures. This refers to the "3 Rs"
Reduce, Reuse and Recycle, which classify waste management strategies
according to their desirability in terms of waste minimization (Anon
[a], 2011). However, this technique is not extensive enough. Before the
waste hierarchy is effectively applied, it is desirable to identify,
classify and estimate the quantity or the volume of waste to be
generated. An effective waste management technique must incorporate all
these factors.
The volume of drilling waste generated when drilling a well is also
an important and costly factor, especially when the waste must be
transported, treated, or disposed off-site(Fleming, et al., 2010). It is
an important planning tool which is usually not mentioned in the
drilling waste management process. Drilling waste could be better
managed if the anticipated amount or volume is appropriately quantified.
Unfortunately, very few publications have reported on drilling waste
volume quantification and estimation methods. This study seeks to
identify the various types of drilling wastes that pollutes the
environment and how to minimize it. It presents an effective method to
quantify the volume of drilling waste generated for an efficient waste
management plan.
1.2 Literature Review
Environmental pollution and waste management is a broad and extensive
study area with lots of publications. There is a tremendous amount of
valuable information available on the environmental impact of petroleum
operations and on ways to minimize that impact: however, this
information are scattered among thousands of books, reports and papers
making it difficult for industrial personnel to obtain specific
information on controlling the environmental effects of particular
operations (Reis, 1996). Again, very little of these materials focuses
on waste volume quantification.