To better understand what lies ahead of the bit as they drill to target formations, operators turn to earth models.  Earth models incorporate geology, formation mechanical properties, in situ stresses, pressure, and temperatures garnered from seismic and offset well data. Intrinsic to the earth model building workflow is the ability to integrate measurements and data across scales within a time frame that has material benefit to reducing uncertainty inherent to the E&P process.

Drilling engineers use the models to develop drilling programs—plans for how and when to perform each depth and time-related procedure required to drill wells optimally to total depth. But using earth models and measurement- and logging-while-drilling tools to capture real-time well data has limits. Nonproductive time (NPT) can occur as drillers stop to adjust parameters in response to unexpected and challenging well conditions.

One solution to drilling NPT is to reduce uncertainty ahead of the bit. SGD Seismic Guided Drilling, the integration of surface seismic and downhole measurements, offers look-ahead predictive models in relevant drilling time to help operators anticipate and respond to potential changes in drilling conditions. 

An article in the Oilfield Review, “Reducing Uncertainty Ahead of the Bit,” describes how the SGD solution equips geologists and drilling engineers with knowledge about subsurface conditions as the well is being drilled. Case histories from West Africa and China demonstrate its application. 

Oilfield Review is the Schlumberger flagship journal of technology, innovation and the science of E&P.  

Reference

Esmersoy, C., Hawthorn, A., Li, H., Shi, H., Liu, X., Xue, F., Yang, S., and Zhang, H.:  “Reducing Uncertainty Ahead of the Bit,” Oilfield Review (May 2015), 27, No. 1: 14–25.