Wireline Formation Testing - Open Hole Logging | SLB


3D radial probe

Saturn 3D Radial Probe for Fluid Sampling and Pressure Measurement hero banner

Fluid flow and pressure data where conventional probes cannot function

Available in three tool diameters, the family of Saturn 3D radial probes brings the efficiency of zero-sump, large inlet area, circumferential flow to previously inaccessible fluids and reservoir environments:

  • rugose or unstable boreholes
  • thinly laminated formations
  • tight, low-permeability formations
  • unconsolidated formations
  • heavy oil or near-critical fluids.

79.44-in² surface flow area: industry’s largest
0.01-mD fluid extraction permeability
30,000-psi pressure rating
400-degF temperature rating
8,000-psi differential pressure
Saturn 3D Radial Probe tool sizes

Circumferential fluid extraction while supporting the sandface

The drain assembly of the Saturn 3D radial probe positions four self-sealing suction ports at 90° intervals against the borehole wall to pull fluid circumferentially from the reservoir instead of funneling it to the single access point of a conventional probe. Because fluid is extracted across a large reservoir volume, flow is readily induced and sustained, even for viscous fluids and in low-mobility and laminated formations, for downhole fluid analysis (DFA) and sample collection.

The assembly also circumferentially supports the formation to prevent sanding and collapse.

Redefine the limits of possible for your wireline formation testing.

Complete pressure surveys in low-permeability, low-mobility formations

The technology that makes the Saturn 3D radial probe excel at fluid extraction also delivers a step change in formation pressure testing. The highest performing conventional tools for pressure-specific formation testing can be applied in mobilities down to 0.1 mD/cP. The Saturn probe can extend this range down by an order of magnitude, to 0.01 mD/cP.

Modeled cleanup times for a conventional extralarge-diameter probe
Modeled cleanup times for the Saturn 3D radial probe and a conventional extralarge-diameter probe show the increase in sampling efficiency possible. The Saturn 3D radial probe is an enabling technology for sampling at mobilities less than 10 mD/cP, at which the conventional probe can no longer perform effectively.
3D radial probe


The Saturn 3D radial probe is deployed with the MDT modular formation dynamics tester to extend formation testing to previously inaccessible fluids and reservoir environments.

Our reservoir evaluation experts meet with you to design the tester configuration incorporating the Saturn probe and specific procedures from the wide variety of available productivity and permeability tests along with fluid extraction and sampling, usually achievable in a single run of the toolstring. Because the Saturn probe extracts fluid across a large reservoir volume, flow is readily induced and sustained for viscous fluids and in low-mobility formations or uncemented matrix.

We monitor in real time the quick removal of filtrate to draw in uncontaminated formation fluid for DFA and sampling. Our multidisciplinary interpretation experts then work with you as needed to leverage this powerful fluid data, such as building predictive reservoir models to determine fluid compositional gradation and reservoir connectivity across the field.

Interpretation Services for MDT Modular Formation Dynamics Tester Configured with Saturn 3D Radial Probe and InSitu Fluid Analyzer System