Understanding the Manifestations of PP and FG Prediction in Challenging Environments - Case Studies

Role of geomechanics in influencing efficient drilling practices is not a new observation in the industry. However, the current petroleum economic situation is demanding even more efficiency in order to save well operations from non-productive time (NPT). Therefore, any non-standard solution that can provide guidance to drill wells efficiently has a strong business value for cost effective well delivery, in addition to HSE compliance. While under-compaction driven normal compaction trends of petrophysical/seismic data offers quantifiable estimates of pore-pressure and fracture gradient, this methodology does not support in any geological setting. Thus, need to find alternative indicators is gaining importance to improve predictability of wellbore behaviour during well planning stage. Complexity of geological setting can sometimes increase the complexity of geomechanical/pressure settings like: HPHT, highly stressed, fractured reservoirs, etc. As no standard methodology exist to predict the pore-pressure and fracture gradient in tectonically active/uplifted and carbonate sedimentary sequences, a holistic methodology was considered to constrain the present day stress/geomechanical setting in which pore-pressure and frac gradients are components. In this way, manifestation of the pore pressure and fracture gradient at diverse geological environments were correlated with diversity in drilling environments. This paper has been explained with few non-standard observations in 3 case studies from different geological and geomechanical settings. Each case offered different lesson as well as challenge.