Ex.2 Put down the words in bold from the text in your notebook and try to explain their meanings to your fellow-students keeping the text covered.

Text 6

Geological Surveys

oil seep - выход нефти, просачивание нефти

exploration well – разведочно-эксплутационная скважина

geological surveys-геологические изыскания

outcropping - выход пласта на поверхность

rock cuttings – частицы разбуренной горной породы

irrigation ditches –оросительные каналы

water well- водная скважина

fluid content- фазовый состав

In the early days of the industry, the only way of locating underground oil and natural gas deposits was to search for surface evidence of these underground formations such as oil seeps, natural gas seeps, pockmarks (underwater craters caused by escaping gas). However, because such a low proportion of petroleum and natural gas deposits actually seep to the surface, this made for a very inefficient and difficult exploration process. As the demand for fossil fuel energy has increased dramatically over the past years, so has the necessity for more accurate methods of locating these deposits.

The exploration typically begins with geologists examining the surface structure of the earth, and determining areas where it is geologically likely that oil or gas deposits might exist. It was discovered in the mid 1800's that anticlinal slopes had a particularly increased chance of containing oil or gas deposits.

By surveying and mapping the surface and sub-surface characteristics of a certain area, the geologist can extrapolate which areas are most likely to contain an oil or natural gas reservoir. The geologist has many tools at his disposal to do so, from the outcroppings of rocks on the surface or in valleys and gorges, to the geologic information attained from the rock cuttings and samples obtained from the digging of irrigation ditches, water wells, and other oil and gas wells. This information is all combined to allow the geologist to make inferences as to the fluid content, porosity, permeability, age, and formation sequence of the rocks underneath the surface of a particular area.

Once the geologist has determined an area where it is geologically possible for a natural gas or oil formation to exist, further tests can be performed to gain more detailed data about the potential reservoir area. These tests allow for the more accurate mapping of underground formations, most notably those formations that are commonly associated with natural gas and oil reservoirs. These tests are commonly performed by a geophysicist, one who uses technology to find and map underground rock formations.

Ex.1 Answer the questions:

1. What kinds of surface evidence of hydrocarbon underground formations do you know?

2. How does exploration usually start?

3. What geological areas have most chances of containing oil or gas deposits?

4. What inferences can geologist make after geological surveys?

5. What is the difference between the work of a geologist and a geophysicist?