Drilling horizontal wells with pilot hole elimination in challenging geological scenarios

Drilling horizontal wells is becoming an increasingly practice in hydrocarbon field development. Technology evolution reduced risks associated to drilling operations and increased accuracy in well placement operations.

Despite this, uncertainty related to subsurface geological and structural setting remains significantly high, and represents a risk factor that can compromise well results.

Moreover, in presence of complex or heterogeneous geological scenario, relying on offset well correlation or drilling pilot hole could not be the proper solution.

The introduction of an ultra-deep directional resistivity tool has provided the industry’s first reservoir-scale imaging while drilling, allowing landing or geo-stopping operations being less critical than in the past. This tool investigates a large volume of the target reservoir, providing different output like 2D map of the resistivity formation around the borehole, supporting real time decision-making processes.

Through the description of three case histories (Sahara Desert, North-East Africa and offshore Timor Sea), it will be demonstrated that the use of the ultra-deep directional resistivity tool in horizontal wells, supports strategic decisions in hazardous geological environment, enabling the elimination of pilot hole and resulting in a significant project’s risks decreasing and costs saving