Deviated and Horizontal Wells Drilling Technology in Coal Seams

Abstract

Drilling in coal seams becomes more and more popular at the present time, especially due to the fact that coal can be exploited not only by subsurface or surface mining methods but also in much cleaner way – underground coal gasification. The presented article is focused on the modern drilling technologies (used in drilling of deviated and horizontal wells needed for underground coal gasification), their advantages and drawbacks. The end of the article is dedicated to the method of the calculation of trajectory coordinates for a deviated well.

Keywords

• horizontal well drilling
• underground coal gasification
• trajectory calculation