How does directional drilling reach petroleum reservoirs beneath lakes, towns, or harbours?

Directional drilling allows for the extraction of petroleum from reservoirs located beneath sensitive or inaccessible areas, such as lakes, towns, or harbours, by offsetting the surface equipment from the target formation.1

The process begins by drilling a vertical well to a specific depth. Once the desired "kickoff point" is reached, the borehole is gradually angled to intersect the underground formation at the intended location. Because the drill pipe is relatively inflexible, the angle is changed incrementally, creating a large arc to reach the objective.12

Modern techniques to achieve this deviation include:

• Steerable Motor Assemblies: These use positive-displacement motors with adjustable bent housings that misalign the bit face, forcing the drill to change direction.1
• Rotary Steerable Systems (RSS): These advanced systems allow for vertical, curved, and horizontal drilling in a single trip by using a closed-loop control system that communicates between the surface and downhole tools.1

By fanning out multiple boreholes from a single surface structure, operators can access various deposits or reach previously inaccessible areas of a reservoir while keeping surface operations at a safe, offset distance.12