![Page 1: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/1.jpg)
GEOPHYSICAL METHODS OF HYDROCARBON EXPLORATIONM.T.H
![Page 2: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/2.jpg)
What is Geophysical Exploration?
• The application of the principles of physics to the study of the subsurface, in search of hydrocarbon
• Geophysical investigations of the interior of the earth involves taking measurements at or near earth’s surface that are influenced by the internal distribution of physical properties.
• The objective of any exploration venture is to find new volumes of hydrocarbons at a low cost and in a short period of time.
![Page 3: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/3.jpg)
Introduction
• The usual sequence of activities once an area has been selected for exploration starts with the definition of a basin.
• Petroleum exploration and production are concerned with the geological interpretation of geophysical data, especially in offshore areas.
• There are three main geophysical methods used in petroleum exploration: Magnetic, gravity and seismic.
• The first two of these methods are used only in the predrilling phase. Seismic surveying is used in both exploration and development phases.
![Page 4: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/4.jpg)
![Page 5: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/5.jpg)
Gravity Surveying
![Page 6: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/6.jpg)
![Page 7: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/7.jpg)
![Page 8: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/8.jpg)
![Page 9: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/9.jpg)
Interpretation of gravity maps presents many problems, the simplest of which are caused by different subsurface bodies producing the same anomaly on the surface.
Example: distinguishing between a small sphere of large density and a large sphere of low density at similar depths is impossible.
In some circumstances gravity maps may indicate drillable prospect by locating salt domes and reefs (because of their low density.
![Page 10: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/10.jpg)
![Page 11: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/11.jpg)
![Page 12: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/12.jpg)
Magnetics
![Page 13: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/13.jpg)
![Page 14: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/14.jpg)
![Page 15: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/15.jpg)
![Page 16: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/16.jpg)
![Page 17: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/17.jpg)
Seismic Geophysical Survey
• The seismic methods are the most widely used of all geophysical methods used in petroleum exploration.
• Seismic methods measure seismic velocity of rock layers to detect both lateral and depth variations and the objective is to determine the lithology and geometry of the layers.
• A seismic wave can be thought of as shock wave (elastic wave) or vibration traveling through the ground.
• The rate of travel, or velocity, of the wave is related to the density of the rock.
• There are two types of elastic waves produced: 1) P-waves, which are primary or “compressional” waves, and 2) S-waves, or shear waves
![Page 18: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/18.jpg)
Sou
nd a
s a
Tool
HydrophoneStreamers
Airgun
Sound Wave
![Page 19: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/19.jpg)
Activity
V=D/Twhere:V = velocityD = distanceT = time
Distance
Time = 0.7 secondsVelocity = 1.4 km/second
![Page 20: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/20.jpg)
Procedure
• The procedure used is to lay out a survey line with geophones set at equal spacings along the line.
• A shock wave is produced at one of the stations by dropping a heavy weight or detonating an explosion at a “shot point”.
• The shot point is the point on the surface directly above the zone of interest.
• Ground motions caused by the explosion or impact are transmitted in the form of P-waves and S-waves.
• A “seismic timer” is used to measure the travel time of the wave from the instant it is generated until the time the wave reflection is detected back at the surface.
• Times are measured for each of the successive stations along the line. Either semi-graphical or computer methods are used to determine the velocities.
![Page 21: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/21.jpg)
![Page 22: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/22.jpg)
![Page 23: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/23.jpg)
![Page 24: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/24.jpg)
![Page 25: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/25.jpg)
![Page 26: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/26.jpg)
![Page 27: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/27.jpg)
![Page 28: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/28.jpg)
![Page 29: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/29.jpg)
![Page 30: Geophysical Methods of Hydrocarbon Exploration](https://reader034.vdocuments.us/reader034/viewer/2022050705/54c57b4f4a7959302b8b47d3/html5/thumbnails/30.jpg)
Questions?