Oil and Gas Exploration Surface Geology

In Oil and Gas Exploration Surface Geology lesson, we discuss how Exploration is begun by gaining an understanding the surface geology.

Understanding Surface Geology

Finding highly productive “sweet spots” in frontier areas depends on the proven principle that the surface geology can give important clues to the subsurface.

Shooting seismic is costly. So operators reserve seismography for areas that already show geological promise.

A stepwise approach has proven to be successful in delineating potential drill sites in new locations.

The starting point is a thorough examination of the structure and geology of the basin, plays and the prospect area.

Next, regional reconnaissance using Landsat images or other airborne radar data is used to identify surface geological indicators than can indicate subsurface faults and structures.

Finally, the potential play areas are high-graded using data from a high-resolution aeromagnetic survey to identify targets and prospects.

Learn More About Oil and Gas Exploration Surface Geology with Oil 101

CLICK HERE TO LEARN MORE ABOUT OUR ONLINE OIL AND GAS TRAINING CERTIFICATE.

Landsat Imaging

Satellite images have been taken of the earth since 1972 by the USGS (US Geological Service). Real time data is available on their website.

Today, explorationists make use of detailed Landsat data as a very cost-effective starting point for examination of frontier basins, to determine accessibility and high level surface geological details.

In April 2008, Landsat data became available to the public for free.

Landsat scenes can be requested and downloaded from

Glovis or
Earth Explorer .

Aeromagnetic Surveys

An aeromagnetic survey is a fast and cheap type of geophysical survey carried out using a magnetometer aboard or towed by a helicopter or an aircraft. Use of aircraft allows large areas of the Earth’s surface to be covered quickly for regional reconnaissance. Aeromagnetic surveys can also be conducted in shallow coastal waters.

The aircraft typically flies in a grid like pattern with height and line spacing determining the resolution of the data. As you can imagine, the resolution in turn determines the cost of the survey per unit area.

As the aircraft flies, the magnetometer records tiny variations in the intensity of the earth’s magnetic field. Different rock types differ in their content of magnetic minerals. For example, the most common sedimentary rocks are sandstone and limestone, and they have low density and are not very magnetic.

The aeromagnetic survey data, once processed, allows a three dimensional visualization of the subsurface geological structure of the Earth’s upper crust. Salt domes, folds and faults can also be identified.