Looking for oil and gas is a job very long and complex many stages. Each stage must be thorough and accurate exploration data generated so accurate, so that in the process of lifting successful oil production, not dry hole and failures occur in drilling process.
The following stages of data collection prior to drilling (drilling)
- Gravity surveys: data collection method is by measuring the difference in gravity caused by differences in the density of material in the geological structure of the earth's crust.
- Magnetic surveys: is the method of measurement of the earth's magnetic field differences due to differences in the magnetic properties of the metal content of the rocks in the soil depth.
Both methods of investigation on the initial investigation conducted in the area is estimated there are deposits / reserves of oil and gas such as a basin (basin). From the data of magnetic and gravity survey was then conducted mapping areas that are economically profitable when done exploration, then the area is estimated to have oil content is mostly done more in-depth survey with seismic methods.
Seismic survey is by reflecting the shock wave (shock-wave) is directed to an artificial reservoir and surrounding areas through the rocks and captured by means of receivers. By various layers of material in the basement, this shock wave will be reflected to the surface as the pulse pressure (by hydrophones in the water) or as acceleration (by geophones on land). Reflected signal is then digitally processed into a subsurface acoustic maps to then be visualized.
Application of seismic methods:
Exploration stage: to determine the structure and stratigraphy of sediment where wells will be dug.
Assessment and development stages: to estimate the volume of hydrocarbon reserves and to plan the development of the most good.
In the production phase: to monitor the condition of the reservoir, such as analyzing the contact between the fluid reservoir (gas-oil-water), the distribution of reservoir fluid and pressure changes.
After evaluating the content of the oil in the reservoir, the next stage is to build a sub-surface facilities (Well-construction) includes drilling (drilling), install tubular wells (casing) and cementing (cementing). Then to make the well completion process is ready for use. This process includes a perforated pipe that is perforating the casing; installation of all of the pipes and the packer and its accessories to bring oil and gas to the surface; installation of wellhead (wellhead or Christmas tree) at the surface; installation of various safety equipment, the installation of the pump if necessary, etc. If needed, the method of stimulation was also performed in this phase. Further well-evaluation to evaluate the condition of wells and formations in the well.
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