Depth conversion is an important step of the
seismic reflection method, which converts the acoustic wave travel time to actual depth, based on the acoustic velocity of subsurface medium (sediments, rocks, water).
Depth conversion integrates several sources of information about the subsurface velocity to derive a
three-dimensional
In geometry, a three-dimensional space (3D space, 3-space or, rarely, tri-dimensional space) is a mathematical space in which three values (''coordinates'') are required to determine the position (geometry), position of a point (geometry), poi ...
velocity model:
* "Well tops", i.e., depth of geological layers encountered in
oil and
gas well
A well is an excavation or structure created on the earth by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...
s
*
Velocity
Velocity is a measurement of speed in a certain direction of motion. It is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of physical objects. Velocity is a vector (geometry), vector Physical q ...
measurements made in oil and gas wells
* Empirical knowledge about the velocities of the rocks in the area investigated
*
Root Mean Square
In mathematics, the root mean square (abbrev. RMS, or rms) of a set of values is the square root of the set's mean square.
Given a set x_i, its RMS is denoted as either x_\mathrm or \mathrm_x. The RMS is also known as the quadratic mean (denote ...
(RMS)
stacking velocities which are derived from the processing of the seismic reflection data
The conversion permits the production of depth and thickness maps that depict subsurface layers that are based on reflection data. These maps are crucial in
hydrocarbon exploration
Hydrocarbon exploration (or oil and gas exploration) is the search by petroleum geologists and geophysicists for hydrocarbon deposits, particularly petroleum and natural gas, in the Earth's crust using petroleum geology.
Exploration methods
...
because they permit the volumetric evaluation of gas or oil in place. In the example subsurface map presented below, depth increases from red to blue. The highest zone in red is an oilfield at approximately 3000 m below sea level.
See also
*
Petrel (reservoir software) – Commercial software from Schlumberger
*
Petroleum geology
Petroleum geology is the study of the origins, occurrence, movement, accumulation, and exploration of hydrocarbon fuels. It refers to the specific set of geological disciplines that are applied to the search for hydrocarbons ( oil exploration).
...
*
Seismic Unix – open source seismic software
External links
* Depth conversio
definitionin the ''Oilfield Glossary''
Seismology measurement
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