1. UNIVERSITY OF AZAD JAMMU AND KASHMIR MUZAFFARABAD PRESENTED
TO: Respected Sir Fahad Sab PRESENTED BY: Azhar Mahmood Roll No:
225 Date : 15/01/2015
2. PRESNETATION # 01 TOPIC Applications of the following
Gravity survey Magnetic survey Electrical resistivity survey
Seismic survey
3. 01: GRAVITY SURVEY METHOD
4. Definition: It is a method of measuring the force of gravity
in drill holes by means of gravimeters in order to determine the
mean density values of rocks at differen t depths in their natural
bed.
5. Application of Gravity Method Survey:
6. Hydrocarbon exploration Regional geological studies
Isostatic compensation determination Exploration for mass
estimation of mineral deposits Detection of subsurface cavities
Location of buried rock valley Determination of glacier thickness
Shape of earth(geodesy) Monitoring volcanoes
7. Hydrocarbon exploration This is also called oil and gas
exploration is the search by geophysicist for hydrocarbon deposits
beneath the Earth's surface such as oil and natural gas . Oil and
gas exploration are grouped under the science of petroleum
geology.
8. Engineering application Gravity surveys can be carried out
to locate iron rich accumulations within furnace, cinder piles
.
9. Accumulations Of Hydrocarbons Gravity Surveys are used
either alone or in conjunction with magnetic surveys, to determine
the location and size of the major source structures which contain
accumulations of hydrocarbons.
10. Hydrogeology Determination of the major structures that
control the location of aquifers. Additionally, Magneto telluric
and Magnetics surveys may also be used for the same purpose
11. The gravity method is a nondestructive geophysical
technique that measures differences in the earths studies including
locating voids and karst features, buried stream valleys, water
table levels and the determination of soil layer thickness.
12. karst features
13. Gravity data in engineering and environmental applications
should be collected in a grid or along a profile with stations
spacing 5 meters or less. In addition, gravity station elevations
must be determined to within 0.2m Using the highly precise
locations and elevations plus all other quantifiable disturbing
effects, the data are processed to remove all these predictable
effects.
14. 02: Magnetic survey method
15. Magnetic survey Magnetic survey is one of a number of
methods used in archaeological geophysics Magnetic surveys record
variation in the Earth's magnetic field. In archaeology , magnetic
surveys are used to detect and map archaeological artifacts and
features. Magnetic surveys are used in both terrestrial and marine
archaeology.
16. Basic Concepts The Earth possesses a magnetic field caused
primarily by sources in the core. The form of the field is roughly
the same as would be caused by a dipole or bar magnet located near
the Earth's center and aligned sub parallel to the geographic
axis
17. Magnetic survey of an archaeological site
18. APPLICATION OF MAGNETIC METHOD SURVEY
19. Locating buried Pipes, cables, tank and drums Fault studies
Ore exploration identification of metalliferous deposits, for
example massive sulphides Geothermal exploration Mapping buried
utilities
20. Exploration of fossil fuels (oil and gas) Exploration of
ore deposit Regional and global tectonics Large scale of geological
structures ,volcanology Engineering construction site investigation
Burried foundation ,fine pits for archeology Mineral
exploration
21. Locating buried Pipes, cables, tank and drums Magnetic
geophysical surveys measure small, localized variations in the
Earth's magnetic field. The magnetic properties of naturally
occurring materials such as magnetic ore bodies and basic igneous
rocks. Magnetometer surveys find underground storage tanks, drums,
piles and reinforced concrete foundations by detecting the magnetic
anomalies they produce.
22. Exploration Mineral Magnetic survey, one of the tools used
by exploration mineral-bearing ore bodies or even oil-bearing
sedimentary structures and locate on map the remains of buried
structures.
23. Marine Magnetic Methods Magnetic methods, as employed in
marine applications, differ little in theory from surface magnetic
surveys. The instrument measures the earths total magnetic field at
each measurement location. However, practical applications of field
techniques, field equipment, and geographic control can vary
greatly between surface and marine surveys.
24. Magnetics surveys measure the magnitude and orientation of
the Earths magnetic field. Magnetic field at Earths surface depends
on field generated in Earths core, magnetic mineral content of
surface materials, and remnant magnetization of surface rocks.
25. 03: Electrical Resistance Survey Method
26. Definition: Electrical resistance survey also called earth
resistance or resistivity survey is one of a number of methods used
in archaeological geophysics. In this type of survey electrical
resistance meters are used to detect and map subsurface
archaeological features and patterning.
27. Electrical resistance survey of an archaeological site
using a twin probe system. (Wenner electrode array.)
29. The presence of certain metallic ore The temperature of sub
surface Geothermal energy The presence of archeological feature
Graves Fire pits Pot holes .
30. Amount of ground water present I. Amount of dissolved salt
II.Presence of contaminants III.% porosity and permeability
31. Specific Applications Determine electrical characteristics
of surrounding area. Determine depth of water table Detect
contaminant plumes Determine extent of saltwater intrusion Detect
fracture zones and faults Detect areas of potentially unstable
ground, e.g. mine shafts, sinkholes, voids
32. Assist in dam stability analysis Determine overburden depth
Locate buried mafic dikes Provide data for corrosion control design
Determine lithology/structure.
33. Electrical resistivity method is also useful for
simultaneously detecting lateral and vertical changes in subsurface
electrical properties
34. 04 :Seismic Surveys Methods
35. Definition Seismic survey, method of investigating
subterranean structure, particularly as related to exploration for
petroleum, natural gas, and mineral deposits. A seismic survey is a
technique similar to an ultrasound that is used to develop images
of the rock layers below ground.
36. Seismic Surveys Methods
37. Applications Seismic Surveys Methods
38. Seismic surveys are used to locate and estimate the size of
offshore oil and gas reserves. To carry out such surveys, ships tow
multiple air gun arrays that emit thousands of high-decibel
explosive impulses to map the seafloor. The auditory assault from
seismic surveys has been found to damage or kill fish eggs and
larvae and to impair the hearing and health of fish and marine
mammals.
39. Hydrocarbon exploration It is used by the hydrocarbon
industry to provide a high resolution map of acoustic impedance
contrasts at depths of up to 10 km within the subsurface. This can
be combined with seismic attribute analysis and other exploration
geophysics tools and used to help geologists build a geological
model of the area of interest.
40. Land survey Land seismic surveys tend to be large entities,
requiring hundreds of tons of equipment and employing anywhere from
a few hundred to a few thousand people, deployed over vast areas
for many months.
41. Marine survey Traditional marine seismic surveys are
conducted using specially-equipped vessels that tow one or more
cables containing a series of hydrophones at constant
intervals
42. Seismic surveying is also play vital part of exploring for
oil and gas. That makes it critical to producing the energy we need
to power our homes and businesses.