MDD-Rigs serve among other applications to extract coal bed methane.

The drill mast of the MDD-Rig has a pull force of up to 600 tonnes and can be inclined from 6° to 90° thus offering completely new possibilities for the execution of both vertical and horizontal drillings.

For this purpose Prime Drilling has developed the MDD-Rig. MDD-Rig means Multifunctional Directional Drilling Rig“.

MDD-Rigs can be used for both horizontal and vertical directional drillings under compliance with the highest safety standards.
The coal gas is extracted via vertical drillings, which reach deep into the coal bed and which are linked with each other afterwards by horizontal directional drilling within the top layer of the coal bed. Due to the closed circuit of the system a coal deposit can be almost completely degassed by this method. The coal bed methane produced is mainly used for power generation and for reducing the gas content in coal deposits to such an extent as to enable extraction of the coal without any risk to operational safety.

Firstly horizontal blind-hole drilling of lengths up to 1,800 m and vertical drillings of depths up to 350 m can be executed. These vertical drillings need to be connected with the horizontal drillings and are thus equipped with reference sensors, signals from these sensors are detected and captured by the horizontal directional drilling rig. Once the required depth within the top layer of the coal bed is reached, the horizontal drilling is directed from horizontal drilling to vertical drilling until the target point is met. Then wash-over rods are sunk down to the drill head to enable installation of filter pipes into the empty rods. After successful drainage the filter pipes are used for degassing and the coal bed methane which is produced is used for power generation.

Range of application:

• for extraction of coal bed methane (degassing)
• for construction of drainage systems for protection of facilities and built-up areas
• for exploration of crude hydrocarbons in coastal zones
• for installation of pipelines under rivers with major differences in elevation