Spectroscopic Logging - Spectroscopy - Characterization | Schlumberger

Pulsar

Multifunction spectroscopy service

Get openhole logging quality in cased hole environments

Pulsar multifunction spectroscopy service pairs multiple detectors with a high-output pulsed neutron generator to provide stand-alone cased hole formation evaluation and reservoir saturation monitoring—all with a single tool. The result is comprehensive reservoir rock and fluid content data that is comparable to data acquired during openhole logging to improve your completion designs and maximize production.

Achieve faster results with better data

The high neutron output and improved acquisition accuracy of Pulsar service significantly increase logging speed and measurement precision in obtaining

  • suite of self-compensated traditional cased hole measurements: sigma, porosity, carbon/oxygen ratio
  • expanded set of elements including total organic carbon (TOC)
  • new fast neutron cross section (FNXS) measurement that differentiates and quantifies gas-filled porosity from liquid-filled and tight zones.
HiWay Horizontal log

The answer for unconventional reservoirs: Cased hole formation evaluation that includes TOC.

Pulsar service measures a greatly expanded suite of elements in cased hole wells as independent, high-quality sets of neutron capture and inelastic scattering spectra.
Pulsar service measures a greatly expanded suite of elements in cased hole wells as independent, high-quality sets of neutron capture and inelastic scattering spectra.

Eliminate NPT while drilling and mitigate risks during cased hole logging

Unlike conventional cased hole logging, no openhole data input is necessary to obtain a high-resolution volumetric petrographic interpretation, so rigless well logging can be conveniently conducted without disrupting drilling operations. Logging a well after it has been cased also negates well instability risks—especially in laterals and shale reservoirs.

Saturation determination in all well and reservoir environments

Because Pulsar service does not depend on conventional resistivity-based approaches to rock and fluid identification, it accurately determines saturations in any formation water salinity, and it can be deployed across a wide range of well conditions:

  • mineralogy, lithology, and fluid content profiles at any well inclination: horizontal, deviated, and vertical
  • hydrocarbon identification in low-resistivity pay
  • corrosion-resistant and NACE MR0175–compliant housing
  • unlimited operation time for the 1.72-in-diameter tool at up to 175 degC without a flask.
Pulsar
Multifunction spectroscopy service

The science of spectroscopy

Pulsar multifunction spectroscopy service provides the key quantitative measurements of elements and mineralogy for cased wells, delivered at higher accuracy and speed than previously possible.

1. Spectral acquisition

The spectroscopy workflow begins with measurement of the separated inelastic and capture gamma ray spectra.

2. Spectral stripping

Each spectra is decomposed into the combination of standard spectra from individual elements. This step involves correction for some environmental and electronic factors.

3. Elemental weight fractions

The coefficients of the linear combination of the standard spectra are converted to elemental weight fractions via a modified geochemical oxides closure model or by using an inversion approach.

4. Interpretation

Two approaches are available to generate mineralogy and lithologic fractions from the elemental concentration logs. One is sequential SpectroLith spectroscopy lithology processing and the other uses an iterative inversion technique, such as the the Quanti.Elan multicomponent inversion solver in the Techlog wellbore software platform.

Pulsar multifunction spectroscopy service provides the key quantitative measurements of elements and mineralogy for cased wells, delivered at higher accuracy and speed that previously possible.
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