Oil and gas seeps have been known since earliest recorded history. Sticky black asphalt was used by the Babylonians as a roofing material, the ancient Egyptians used it to preserve their dead, and Noah supposedly caulked his Ark with it. In Azerbaijan gas seeps have burned for centuries, and therefore it is perhaps surprising that the world's first major underground oilfield was discovered in Pennsylvania, USA only as recently as 1859. That discovery launched an era in which the world became increasingly reliant on cheap energy provided by oil and gas, a reliance assured by the invention of the internal combustion engine in the late 19th century. Only now, as the issues of long-term sustainability and climate change become more apparent, are we beginning to think about unshackling ourselves from that dependency.

This unit begins by examining the geological characteristics of petroleum and the key ingredients necessary to form oil and gas accumulations. Then there is a brief description of industrial operations during the life cycle of an oilfield, starting with subsurface analysis and exploration drilling. The unit also highlights the role of safety and environmental management as an integral part of the petroleum business and concludes with a short review of global resources and non-conventional petroleum.

You will find definitions of terms highlighted in bold in the glossary towards the end of this unit (use the 'Jump to' facility on the navigation bar above).

Learning Outcomes

When you have completed this unit, you should be able to explain in your own words, and use correctly, all the bold terms printed in the text. You should also be able, among other things, to do the following:

  • Interpret graphs and evaluate tables of data relating to different aspects of petroleum.
  • Given basic geological information for a petroleum play, recognise the main ‘ingredients’ (petroleum charge, reservoirs, seals and traps) that contribute to its potential.
  • Understand the roles played by different means of exploration in contributing to defining a petroleum play, and its evaluation.
  • Describe the various options for petroleum production in different settings.
  • Discuss the various hazards to operators and the environment that are presented by exploiting petroleum reserves.
  • Understand the criteria used in assessing petroleum reserves globally and in the UK.
  • Discuss the conditions under which unconventional petroleum resources form, and the requirements for their future exploitation.