Fractured Reservoirs

Characterize fractured reservoirs to optimize drilling and completions

Natural fractures and faults are the primary pathways for hydrocarbon migration and production in many reservoirs. Unfortunately, they can also act as channels for water breakthrough and gas coning. Knowledge of these fractures and their conductivities in relation to rock stresses helps reservoir engineers and geoscientists to optimize reservoir and well performance.

Stress affects fracture permeability

Natural fractures (i.e., those created over geologic time) and the geostresses currently acting on them influence their permeabilities and the potential to slip. Critically stressed fractures sometimes serve as highly efficient pathways for fluid migration. The stress regime acting in a reservoir and the orientations of any fracture set in relation to these stresses is a major control on the permeability anisotropy of the fractured reservoirs.

When depletion or injection occurs, pressure changes can lead to stress changes that further modify the apertures, and hence, the permeabilities, of the fractures. Such changes can be dynamic over the life of a field, meaning that fracture permeabilities and preferred flow directions can change with depletion and injection.

Schlumberger geomechanics experts generate mechanical earth models (MEMs) that describe rock stresses and rock mechanical properties. Utilizing these data with other information on fractures from FMI Fullbore Formation MicroImager logs and the new Sonic Scanner acoustic logs, we turn this information into an understanding of fracture conductivities and descriptions of how these conductivities will change over the life of a field.