StethoScope Formation Pressure-While-Drilling Service | SLB


Formation pressure-while-drilling service

Two Schlumberger technicians making final preparations to a StethoScope formation pressure-while-drilling service tool

Calibrating pore pressure models

The StethoScope service provides formation pressure-while-drilling (FPWD) measurements that are used to predict pore pressure trends throughout the wellbore. Profiles generated by the service’s real-time calibration points combine with other LWD logs to model dynamic reservoir pressure, which is crucial to optimizing recovery. These pore pressure models also foster a better understanding of production systems.

Optimizing mud weight and casing placement

The use of real-time LWD measurements—specifically resistivity and sonic measurements—to predict pore pressure trends provides data assurance in any hole deviation or orientation. Once the pore pressure is known, mud weight can be optimized, allowing drilling to continue at optimal penetration rates without kicks and drilling delays. Accurate formation pressure evaluation also eliminates costs associated with premature casing runs and incorrect casing placement.

Analyzing virgin and developed reservoirs

In virgin reservoirs, pressure profiles can be combined with other LWD logs to develop a static model of the reservoir. Pressure and mobility data help target the most productive zones and determine the optimal drain length for horizontal wells. In developed reservoirs, pressure profiles also help to evaluate fluid movement, and rapid pressure analysis aids in effective geosteering between compartments in faulted formations.

Three technicians preparing the StethoScope formation pressure-while-drilling service tool to go downhole with the aid of an iron roughneck
Close up of the StethoScope formation pressure-while-drilling service tool

Rapid pressure analysis for keeping in zone

Real-time StethoScope service measurements, delivered to surface by on-demand frame technology, facilitate geosteering and geostopping decisions based on the pressure regimes encountered. Quick decisions can avoid time spent drilling pressure-related formations and preserve virgin pressure zones scheduled for sidetrack development or completion.

Pressure data to surface in real time

  1. As the tool is set, accurate pressure gauges start recording. Pressure data is sent to the surface in real time, and the profile is drawn.
  2. Upon completion of the sequence, the tool is retracted, and drilling resumes.
  3. Final formation pressure points are highlighted on profile (bottom) and transferred to the existing pore pressure model (top).
  4. The pressure model is recalibrated and redrawn with less uncertainty. When pore pressure is known, mud weights can be altered to resume drilling.