Alteration of landscape through the destruction of vegetation is thought to cause climate change, so the production of oil and the emissions from its eventual combustion are both concerns. The search for oil has literally covered the globe. Geologists and wildcatters have pursued the hunt for oil and natural gas on land and sea in all climates. There is an adage: "oil is where you find it," and the search for oil includes tropical rain forests and arctic tundra. These and other locations create significant challenges to production, while maintaining the ecosystem. To begin the search for petroleum, geologic basins are identified. These are large regions where layers of rock were formed through compaction of sediment and chemical action over millions of years. These regions were subsiding and were seas or swamps, so that sediment (material for rock formation) and organic matter (material for petroleum formation) could be deposited.
These geologic basins exist throughout the world on continents and continental margins. The Gulf of Mexico is a geologic basin that is active today because it is a depression that is collecting sediment from drainage off a significant part of North America. It is also receiving deposits of marine organic matter. The Illinois Basin, on the other hand, has thousands of feet of sediment and organic matter, but has not been an active basin for millions of years. In most regions, the surface conditions are not like the conditions that existed at the time the organic material and sediment were deposited.
When a discovery is made, if economic, it is developed. Development requires building roads, drilling wells, and installing separation equipment, storage facilities, and possibly pipelines. In delicate ecosystems, the development and production can potentially harm that system, changing
the landscape, and contributing to climate change. Helicopters are often used to minimize clearing of vegetation and minimizing footprints. Also, drilling technology has improved so that it is now possible to drill a number of wells from one location through a technique known as directional or horizontal drilling.
Other operations also can impact the air and the land. Petroleum may need to be artificially lifted from deep in the Earth. The lifting of petroleum can require enormous amounts of energy. Electricity is used to pump petroleum, and that electricity may come from the electric grid or from generators fueled by diesel or natural gas on location. Over time, the fluid pumped out of the ground will contain an increasing percentage of water and a decreasing percentage of oil. This fluid is separated in the field so that only the oil is transported. The produced water must be properly treated and disposed. Over time, vegetation may be stressed by contaminants related to oil production. Highly mineralized water and sulfur are two potential contaminants that can damage or destroy local vegetation, contributing to a change in the local climate, and possibly the global climate. If not properly cased, well bores can be an unwanted conduit for moving fluid from one rock layer to another, and, thus, saline water can contaminate fresh water. If after abandonment, the integrity of plugging operations is flawed, then near surface aquifers can become contaminated and be a potential threat to vegetation.
Oil is transported for refining by truck, pipeline, and tanker. Tankers can be of enormous size, holding over 2 million barrels of oil. As a comparison, an onshore discovery of one million barrels would be considered respectable today in the United States onshore setting. Albeit small, it might require 20 years to deplete. Although the threat of a supertanker breakup is very low, if such an event were to occur, it would be a concern in the climate change debate. The ocean's plankton create oxygen and its destruction through toxicity or smothering from the oil will kill the plankton. Although a supertanker spill would be a huge scale environmental catastrophe, many can argue that the ocean's massive volumes and surface area reduce such an event to a minor, temporary problem. The oil industry has worked to reduce and eliminate all traces of crude oil in the sea from offshore production facilities. This oil is in trace amounts in the water that is released.
Refineries crack the hydrocarbons into products for marketing. Again, energy is consumed in the process and flares may be needed to burn gases in quantities too small to capture. It is the refined products, primarily gasoline and diesel fuel, that are of concern in the global warming and greenhouse gas debate.
Was this article helpful?