Reservoir Compaction

Predict and Control Reservoir Compaction to Optimize Well Location

Many oilfield projects today are challenging because of geomechanical problems arising from overpressure, wellbore instability, reservoir compaction, casing failure, sanding, surface subsidence, and fault reactivation. The impact of reservoir compaction on field development is best examined early in the life of the field when there is opportunity for proactive planning.

The Schlumberger Geomechanics group uses a workflow based on a developing a 3D mechanical earth model (MEM) to predict reservoir compaction from pressure depletion and its associated impact on casing deformation and surface subsidence. The use of an MEM enables the capture of all information relating to the geomechanics of drilling and production, such as the in situ stresses, rock failure mechanisms, rock mechanical parameters, geological structure, and stratigraphy. The model can then be used to identify geomechanics problems and draw up contingency plans for handling these problems before a well is drilled or the field is put on production.

Geomechanical hot spots—where reservoir compaction is predicted to be greatest—are identified, allowing production strategy to be optimized. Several possible modes of production-induced casing failure are examined, and the likelihood of casing failure is assessed, facilitating development of strategies for either avoiding such risks or reducing their impact.