Abstract
Understanding the spatial variation of stresses and rock mechanical properties is the key to optimize strategies for field development. In geologically complex regions, as faulted and folded domains or areas of lateral facies changes, integration of the geologic structure is crucial to better predict geomechanical attributes. This has been done in an area located in the Llanos Orientales Basin (Colombia) by means of a three-dimensional geomechanical model. The model integrates knowledge of the geological structure and regional stratigraphy, data collected in more than 40 wells, and the drilling experience acquired over 20 years. The result is a high resolution 3D model, easy to handle and to update, with a number of immediate applications that go from field exploration to harvesting and abandoning.
Seismically resolvable faults and horizons have been brought into three-dimensions to build a structural model of the Apiay- Suria region. The structural framework has been used to propagate the geomechanical attributes of a number of wells using geostatistical algorithms. As a result, we have built a 3D model comprising the magnitudes and orientations of the three principal stresses, the pore pressure regime, and rock mechanical properties as uniaxial rock strength, internal friction or Poisson's ratio.
The resulting 3D model provides a high resolution database that maps any lateral variation of the geomechanical attributes across the field and can be used to assess wellbore stability for any future well trajectory and location. The 3D numerical geomechanical model has been also used to determine the stress conditions near the main faults. The stress tensor is here combined with a failure criterion to assess the potential for fault instability. This study provides a valuable insight on the risk of losses while drilling through these faults and the possibility of seal rupture and leakage during injection and hydraulic fracturing activities.
