Depth conversion is an important step of the

seismic reflection Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismi ...

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 Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position of an element (i.e., point). This is the informal ...

velocity model: * "Well tops", i.e., depth of geological layers encountered in

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...

and

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

well A well is an excavation or structure created in the ground 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 the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a ...

measurements made in oil and gas wells * Empirical knowledge about the velocities of the rocks in the area investigated *

Root Mean Square In mathematics and its applications, the root mean square of a set of numbers x_i (abbreviated as RMS, or rms and denoted in formulas as either x_\mathrm or \mathrm_x) is defined as the square root of the mean square (the arithmetic mean of the ...

(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 deposits of hydrocarbons, particularly petroleum and natural gas, in the Earth using petroleum geology. Exploration methods Vis ...

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.

External links

* Depth conversio
definition
in the ''Oilfield Glossary'' Seismology measurement {{Geology-stub

See also

External links