Petrol, Oil and GasOne calls the purposeful search for oil and natural gas deposits geophysical prospection. Under physical prospection understands one application physical setting on the investigation of the upper part of the earth's crust. Safe seeking out in the underground of hidden structures, in which oil and (or) natural gas can have collected, became in the last decades the most important condition of a successful search for hydrocarbons (comprehensive term for oil and natural gas). In the early period of the oil production one was dependent on signs at the earth's surface, which suggested occurrences of oil. Thus oil constantly withdraws in small quantities from shallowly lying stores. The search for deeply lying oil fields took place in former times via a detailed analysis of geological conditions of a region. In the consequence at selected places sample drillings were then down-brought, of which approx. 10 became 15% found. At the beginning of the investigation finding sediment basins stands. That is done frequently via gravimetric or geomagnetic measurements. In the next step the reflection seismology is used.
At the earth's surface acoustic waves are produced, which are reflected at the different Bodenschichten. Depending upon employment ashore or in the water different procedures are used. Sources of seismic waves ashore are explosives, drop weights or seismic vibrators. At the earth's surface laid out geophones serve as sensors for the recording of the waves. In the marine seismology the seismic waves with Airguns are produced. The recording of the waves takes place with Hydrophonen, which either at the bottom of the sea laid out or behind a ship at the sea surface in drag are pulled. By the running times and characteristics of the reflected signals layer profiles can be calculated. In the early phase of the prospection 2D-measurings are accomplished, in whose result one receives layer profiles along crossing Messlinien. Thus economically larger areas can be explored. Based on the seismic data now also first investigation drillings are transacted. In the next step in selected areas seismically 3D-measurings are accomplished. Here the points are laid out in such a way for producing and measuring seismic waves that one receives a three-dimensional picture of the rock formations. In combination with borehole-geophysical measuring data now a quantitative model of the oil or natural gas reserves as well as a plan for further drillings and for promotion can be provided.