Estimation Of Drilling Wastes – An Environmental Concern While Drilling Oil And Gas Wells

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.