ZBE - Vertical Drilling Systems

ZBE - Drilling System

The ZBE-System is a vertical directional rotary drilling system. Directional drilling is of prime importance in the drilling of boreholes for many variable applications:
pilot boreholes in coal mining, rock and tunnelling, exploration, oil and gas industry. In all cases the target has to be met accurately and reliably. This is a difficult and onerous job.

Functional Description

For that reason Smart Drilling GmbH has developed, designed and manufactured automatic vertical directional drilling systems ZBE since 25 years.
The ZBE-system, situated directly behind the bit, consist essentially of a shaft connected with the bit and drill string, as well as an external, nonrotating housing with four movable control skids. These skids are pressed against the borehole wall, initiate the controlling motion, and prevent rotation of the housing.
The components of the hydraulic control system, the sensors, and the the electronic system are located in chambers behind these skids. The electric and hydraulic power required by the measuring and control elements is supplied by a generator and pump. The generator is driven by the relative motion between rotating drill pipe and the stationary housing.
The preprogrammed vertical line is continuously measured by highly sensitive accelerometers, whose output signals are transmitted to the electronic control system and thus initiate hydraulic control processes. For this purpose, the control skids are braced against the borehole wall.

Steering principle

For system monitoring and transmission of the measured inclination values during drilling, a wireless data transmission system is employed. The system operates by the positive pressure pulse method: For this purpose, an electrohydraulically driven pulse generator causes a constriction in the drilling fluid channel and thus a pressure increase in the form of a brief pressure pulse, which is detectable in the drilling fluid system at the surface. These pressure pulses are decoded to provide complete data records for display and recording at the receiving station. This procedure ensures continuous data acquisition on the course of the borehole. With ZBE, vertical wells have been drilled for many years at home and abroad with a closely defined target rabge as well as a consistently straight and perpendicular borehole path (more than 120 wells with an accuracy better than 0.1 % of the well length).