The general principle of seismic reflection is
to send elastic waves
(using an energy source such as dynamite explosion or Vibroseis) into the Earth, where each layer within the Earth reflects a portion of the wave’s energy back and allows the rest to refract through.
What is seismic reflector?
A seismic reflector is
a boundary between beds with different properties
. There may be a change of lithology or fluid fill from bed 1 to bed 2.
What is the use of seismic reflection?
The seismic reflection method has been used
to map the thickness of sediments in many parts of the oceans
. Besides thickness, seismic reflection data can often reveal sediment type and the processes of sedimentation.
What is seismic used for?
Seismic surveys use reflected sound waves to produce a “CAT scan” of the Earth’s subsurface. Seismic surveys can help locate ground water, are used to investigate locations for landfills, and characterize how an area will shake during an earthquake, but they are primarily used for
oil and gas exploration
.
Who invented seismic reflection?
The first reflection patent, US Patent no. 1,843,725, was filed on 1 May 1929 by
John Clarence Karcher
… almost 6 months after the discovery well was completed.
What is the difference between seismic reflection and refraction?
In seismic reflection method the waves travel downward initially and are reflected at some point back to the surface, the overall path being essentially vertical. … Whereas, in seismic refraction method, principal portion of the wave-path is along the interface between the two layers and hence
approximately horizontal
.
What is reflection configuration?
Reflection configuration patterns can be divided into three groups:
Parallel
—including subparallel and divergent. Discontinuous. Prograding—caused by lateral accretion of strata.
How do you read seismic data?
The
seismogram
is “read” like a book, from left to right and top to bottom (this is the direction that time increases). As with a book, the right end of any horizontal line “connects” with the left end of the line below it. Each line represents 15 minutes of data; four lines per hour.
Who uses seismic data?
Seismic data are used by
reservoir management teams
to plan and monitor the development and production of a field. Seismic data have the potential to provide the bridge between well logs and core analysis on the one hand, and tracer and well-test analysis on the other.
What is seismic spread?
1. n. [Geophysics]
The geometrical pattern of groups of geophones relative to the seismic source
. The output from a single shot is recorded simultaneously by the spread during seismic acquisition. Common spread geometries include in-line offset, L-spread, split-spread and T-spread.
What is seismic energy?
Seismic waves are
waves of energy that travel through Earth’s layers
, and are a result of earthquakes, volcanic eruptions, magma movement, large landslides and large man-made explosions that give out low-frequency acoustic energy.
What seismic means?
1 :
of, subject to, or caused by an earthquake
also : of or relating to an earth vibration caused by something else (such as an explosion or the impact of a meteorite) 2 : of or relating to a vibration on a celestial body (such as the moon) comparable to a seismic event on earth.
How does 3D seismic work?
3D seismic programs are generally a uniform and
evenly spaced grid of lines
. Receiver lines containing the recording devices (geophones) usually, but not always, run in a direction perpendicular or diagonal to the source lines. The resultant product can be thought of as a cube of common depth point stacked reflections.
What is seismic technology?
Seismic is a
technology that bounces sound waves off rock formations deep below the surface of the earth
to provide explorers with a picture of the subsurface, often revealing locations where oil and gas may be trapped.
Why does refraction occur?
Refraction is an effect that occurs when a light wave, incident at an angle away from the normal,
passes a boundary from one medium into another in which there is a change in velocity of the light
. Light is refracted when it crosses the interface from air into glass in which it moves more slowly.
What causes seismic refraction?
Refraction is (1) the deflection, or bending, of the ray path of a seismic wave caused by
its passage from one material to another having different elastic properties
.
