Borehole drilling is the process of creating an excavation of a cylindrical shape by breaking the rocks at the bottom. As a rule, borehole drilling is carried out in the crust, at least in case of working with artificial materials (concrete, asphalt and etc.). In some cases the process includes fixing the casing walls with the injection of cement slurry into the annulus between the pipe and the walls of the borehole.
The scope for boreholes drilling is extremely diverse and includes a broad variety of aspects, including mineral resources exploration, rocks properties researching; liquid, gaseous and solid minerals production through boreholes drilling; artificial rocks fixing (freezing , bituminization, cementation and etc.); draining flooded areas and wetland for mineral deposits e; laying of underground utilities, construction of pile foundations and etc.
Borehole drilling methods classification
Due to outstanding efficiency borehole drilling and the related fields have formed a separate branch in geophysics. Frankly speaking, the classification of drilling methods is a topic for the whole book, so mentioned below is a brief description on the main directions of the branch.
Therefore, the drilling methods are divided into mechanical ones that imply direct action and non-mechanical characterized by the action (thermal, explosive and etc.) applied to the source of the deposit. Mechanical drilling methods are divided into rotary and percussion (though, they may be combined). In rotary drilling the rock collapses due to rotation of the anchored instrument to its bottom. Depending on the strength of the rock, borehole drilling experts make a decision on the type of drilling tool to utilize (diamond drilling tool or special crowns).
As a rule, a seasoned company is ready to take advantage of any suitable method, meaning its arsenal features the required equipment and staff. If you are looking to have your borehole project delivered quickly and diligently, get in touch with the proven industry professionals –European Geophysical Services. The company has more than 9 years of geophysics and borehole drilling experience accordingly, having delivered over 100 domestic projects in United Kingdom.
Borehole drilling: an excursion into history
Basing on archaeological findings the numerous studies show that a primitive man used drilled holes to excavate various materials more than 25 thousand years ago. In ancient Egypt rotary drilling was used in the construction of the pyramids about 6,000 years ago.
The first reports on Chinese water boreholes are referred to the works of Confucius, written around 600 BC. The boreholes of nearly 900m in depth depicted in the works by a famous philosopher were constructed using percussive drilling. This suggests that before such drilling technique was applied it was needed to be developed for at least a few hundred years.
The documentary evidence of drilling technology is pretty poor; however, judging by the ancient Chinese painting, bas-reliefs, tapestries, murals and embroideries on silk, this technique was presumably highly developed still.
As time passed, the process of borehole drilling has been constantly improved. Thus, walls collapse was a common issue for boreholes, and to resolve the problem our ancestors used hollow tree trunks or pipes to fix the construction.
The first borehole was drilled in the United States: designed for brine extraction it was built in vicinity of the city of Charleston in West Virginia in 1806 (shortly before the emergence of geophysics as a synergy of two sciences). As the excavation works in the region were gaining momentum, borehole drilling method was used more frequently, and 20 years after the local industrialists discovered huge oil deposits.