Chemostrat
Technology
Chemostrat are the only chemostratigraphy service provider able to offer ICP-OES, ICP-MS, WD-XRF, ED-XRF and LIBS analytical options to our customers. This analytical flexibility ensures our clients an optimized and cost-effective analytical regime to suit their individual project needs.
Choosing the most suitable analytical option is important. Our technology falls into two main categories, and although both provide extensive elemental datasets (major and trace elements and REE's), the choice of instrument is based a function of sample volume and lithology:
ICP-OES and ICP-MS (Inductively Coupled Plasma Optical Emission and Mass Spectroscopy)
Advantages:
- Requires minimal sample volume (c.0.25g), especially favorable when dealing with archived washed and dried cutting samples.
- Superior analytical thresholds for very clean sandstones, in resolving low abundance trace elements.
- Provides data for major and high-abundance trace elements (ICP-OES) and ultra-trace elements, including the precious metals and REEs (ICP-MS).
Disadvantages:
- Time consuming sample preparation, either using acid digestion or alkai fusion.
- Full element array often not required.
- Several key elements not obtained, e.g. S, Cl and Br.
WD-XRF and ED-XRF (Energy Dispersive and Wave Dispersive X-Ray Fluorescence)
Advantages:
- Quick and simple sample preparation, either fused bead or pressed pellet.
- Provides data for S, Cl and Br enabling redox and environmental modeling in evaporitic sequences.
- High precision data.
Disadvantages:
- Requires >4g and ideally 4-6g.
- Detection limits on key lements is too high for clean lithologies.
- Lacks rare earth element array obtained by ICP.
WELLSITE INSTRUMENTATION
- ED-XRF (Energy Dispersive X-Ray Fluorescence).
- LIBS (Laser-Induced Breakdown Spectrometry).
Data quality for interpretations is also important and we adhere to strict QA/QC procedures controlled running rock standards of known compositions at the start and end of each batch to correct for machine drift.