Exploratory drilling is an activity aimed at finding raw materials in the bowels of the earth. At the beginning of the 19th century in France in this way they searched for water. In the 1950s, they searched for oil using exploratory drilling .
The essence of the process
Today, exploratory wells are drilled with powerful and sophisticated equipment.
To destroy the rock, a special chisel is used. It joins the drill pipe. In the process of exploratory drilling, the bit wears out, respectively, it needs to be changed. To do this, the pipe string rises up, the worn element is removed, a new one is wound. After that, the entire column sinks into the bowels of the earth again.
A bit has a larger diameter than pipes. After it passes through the formation, a gap remains between it and the pipe. With the help of powerful pumps, drilling fluid is fed into the pipes. It descends first down, and then rises up through the annulus. Upstairs it is cleaned of rock and again pumped into the well. These works are performed by qualified specialists - exploratory drilling drillers . Of course, an entire team works at one facility.
Technology improvement
In 1922, a Soviet engineer Kapelyushnikov proposed a new method of exploratory drilling - turbine. An engine descended to the bottom of the well, due to which the bit rotated. Thanks to this innovation, there is no need to set the entire pipe string in motion, which significantly saves energy.
Subsequently, the method of turbine exploratory drilling was repeatedly improved. Today, a turbodrill is a very complex unit, the length of which is about 10 m. Each stage of the machine is equipped with 2 disks with profiled blades. One of them is the stator. It is fixedly mounted in the unit body. The second is a rotating rotor. The turbodrill is driven by the drilling fluid pumped into the well under pressure. He washes the remains of the rock and cleans the rotor blades.
On each section of the unit, a relatively small power develops. However, the combined strength is enough to destroy even the hardest rocks.
Drilling mud
Its quality is given increased attention. Drilling fluid performs several functions. First of all, he raises the debris of the destroyed rock to the surface. In addition, due to it, the turbodrill is brought into rotation, the bit is cooled.
Previously, water was used as a drilling fluid. It is not currently in use. This is due to the following. Water is really capable of carrying destroyed rock to the surface. However, if the process stops, all debris will begin to settle down. After some time, they will fill the annulus. As a result, all equipment will remain under the debris. It is almost impossible to pull out the unit. All this will entail serious financial losses, since the cost of the machine and its elements is several million rubles.
To avoid such situations, a special clay solution based on clay powder is used. It does not allow the rock to settle if drilling is suspended. After the resumption of the process, the sludge (destroyed rock) will again go up.
Difficulties
When drilling in the bowels, different layers (oil, water, gas) may be present. One of the key conditions of the process is to ensure their integrity.
Suppose a 4-kilometer hole with a diameter of 30 cm has been drilled. Conventional sealing from above will lead to very dangerous consequences. From different layers of the mixture will begin to fill the space. Then from the reservoir, in which the highest pressure, substances will penetrate to other levels. They, in turn, may contain water layers close to the surface. As a result, oil or gas will penetrate into lakes and rivers, city reservoirs.
Solution
To prevent such consequences, during the drilling process, the wellbore is filled with drilling fluid. It prevents the penetration of fractions from the occurring strata into the formed space. But in order to achieve this, a solution of a certain density is required, and it itself must not penetrate into the strata.
Assistant Driller for Production and Exploration Drilling
As mentioned above, several workers are involved in drilling. The brigade includes not only highly qualified drillers, but also support staff.
Driller assistant:
- takes part in the process;
- starts the installation under the control of the driller;
- performs horse-riding during hoisting operations;
- participates in the laying of casing and drill pipes;
- prepares and processes the solution;
- starts, stops the pumps, controls their operation, the level of flushing fluid;
- determines and eliminates malfunctions, replaces worn pump elements.
The duties of the employee also include participation in the elimination of accidents and complications.
Qualification requirements
The driller assistant should know:
- technical regulations on drilling technology, organization of work;
- basic geological characteristics of deposits;
- features of the technological process of oil and gas production, extraction of other minerals;
- technical characteristics and arrangement of tools, equipment, mechanisms, rules for their use.
Since the employee’s tasks include servicing the units, he must know the rules for preparing, cleaning, treating solutions, their main physicochemical parameters, the rules for preparing pipes for launching, drilling installation diagrams, and blowout control equipment operating instructions.