КЕЙС-СТАДИС

Oil and Gas Exploration and Development Process

The main process of oil exploration and development is as follows: Geological Survey - Geophysical Exploration - Drilling - logging - Logging - Completion - Cementing - Perforation – oil extraction - workover - increased mining - transportation - processing. These processes are linked together and are interdependent and inseparable.

Geological exploration is the use of oil exploration and geological knowledge, to carry a compass, a hammer and other simple tools, through direct observation about the exposed ground, rocks, to understand the sedimentary stratigraphic and structural features. They need to collect all the geological data in order to identify favorable areas and distribution of hydrocarbon generation and accumulation, to achieve the purpose of oil and gas fields found. But most of the surface is covered by modern deposition, which makes geological exploration greatly restricted. Geological exploration process is essential, and it greatly reduces the area for next geophysical exploration work to be carried out effectively.

 

Ground geological survey method is generally divided into three steps- census, detailed investigation and fine measuring. Census work is mainly to “seek’. Its basic map sheet called a geological map, which is helplful to find the oil range. Detailed investigation is to “elect “. Based on the census promising area, it need further confirmed to elect more powerful oil-bearing structures. Fine measurement is mainly to "fix" on which is the right configuration by measuring to prepare accurate structural map for further drilling, its purpose is to find the oil and gas fields as soon as possible.

 

Geophysical exploration (referred to geophysical prospecting) is based on the principles of geology and physics, to observe various physical phenomena by different physical instruments, to infer the subsurface geological conditions, to find oil.

 

Geophysical prospecting is a relatively new technology, which includes gravity prospecting, magnetic prospecting, electrical prospecting, seismic exploration and nuclear prospecting.

 (1) Gravity prospecting

Gravity surveys is based on the density differences between the detect objects and their surrounding rock (ore), through observation and study of gravitational field variation, to identify geological structures, to find mineral (mineral) and detection. It is mainly used for petroleum exploration prospect in geological formations, salt domes and delineation of coal basin; It is to study the regional geological structure and geological formation and cooperate with other geophysical methods to find oil and gas resources.

 

 (2) Magnetic geophysical prospecting

Magnetic Geophysical is based on magnetic differences between the detected object and its surrounding rock (ore), through the observation about the variation of the natural and artificial magnetic field, to identify the geological structure, search mineral. It is mainly used for various scale geological mapping, prospecting oil and gas structures and coal basin, research about regional geological structure. It is also used to look for iron ore and metal ore containing magnetic minerals and non-metallic minerals.

 

 (3) Electrical prospecting

Electrical prospecting is based on the difference of electrical properties between rock and mineral. through observation and research about these characteristics differences of electric or electromagnetic field distribution and variation to identify subsurface geological structure and find useful minerals.

 

 (4) Reflected wave method of seismic exploration

In the geophysical exploration, seismic reflection method is a very important method of exploration methods. Seismic exploration method is the use of artificial excitation of seismic wave propagation in the underground geological formations of different elastic to survey the underground situation. Artificial received seismic waves, after the explanation, with the data processing, can be inversed underground geological structure and lithology, achieve the purpose of geological exploration. Seismic exploration methods can be divided into reflected wave method, refraction wave method and the transmission method. Current seismic exploration is mainly based on reflected wave method.

 

 (5) Nuclear prospecting

Nuclear prospecting is based on the differences of radionuclide content and type of rock, natural radionuclide, as well as a variety of physical phenomena in artificial radioactive nuclear excitation rock, or generate by prospecting underground geological formations or look for geophysical methods useful in minerals. That is referred as nuclear geophysical prospecting.