Oil fields search is aimed to discover hydrocarbon accumulations which are perspective with a view to industrial operation and economic efficiency. To do this, exploration activities and operations are performed, including several steps.
At the beginning of oil and gas field search geological data regarding the area potentially rich with raw materials are collected. Searching party employees have unique task: detect where hydrocarbon reserves are hidden in the earth mass, at which depth, in which rocks by content? In a mainland or in a sea offshore.
How are oil fields searched
It is incorrect to say that oil and gas field exploration activities is carried out “blindfolded”. Specialists have equipment for geophysical explorations to obtain preliminary data regarding section structure, information regarding laying rock formations.
One of geophysical exploration technologies (or all together) is applied for hydrocarbon fields search:
- seismical;
- magnetical;
- electrical;
- geochemical.
Using the first three methods blast wave propagation speed is registered, magnetic field at a depth and rock formation electrical resistance is measured. During geochemical exploration of oil fields samples of soil, air on the earth surface are collected in order to determine presence of hydrocarbon atoms in these samples.
Ground waters shall also be studied: here can “live” micro organisms which require organic in formation fluids to support their lives.
Array of collected information is processed. Based on this information 3D or 4D models are generated which show on-line all processes taken place in studied production horizons. However, this is not enough to evaluate reservoir development prospectivity.
The most reliable method to determine reservoir characteristics and evaluate hydrocarbon reserves is exploratory well drilling. Upon completion of these activities, samples of liquid, rocks are collected, formation pressure and temperature are measured. In laboratory conditions reservoir porosity and permeability as well as oil and gas saturation are determined.
This information already allows to evaluate field reserves and make a decision whether it is rational to perform further development.