Textural Analysis provides basic data on sandstone grain size, which almost invariably exerts some degree of control on final reservoir quality (either directly, or indirectly depending upon the degree of diagenetic overprinting). The grain size data is also useful for calibration of core grain size in heavily cemented sediments, where original grain size is not always easy to determine in core, and cannot be measured accurately using bulk approaches (e.g. seive analysis or laser particle sizing).
We provide the raw data, as well as summary statistics including averages, sorting and other measures of spread and skew – including systematic grain size classification (in ½Φ bins).
We offer sample descriptions at a range of level of detail, from summary descriptions focussed on a specific set of feature(s) in a sample or sample set, up to completely-comprehensive characterisation of all aspects of the sample.
SEM Image showing clays on a grain surface, associated with quartz overgrowths and pyrite euhedra.
Most of the descriptive work is carried out using optical (plane-polarised light) light microscopy. However, additional detail will usually be added using scanning electron microscopy and other microscopy methods as required. Any additional micrcoscopy observations are incorporated directly into the sample descriptions (and not presented as separate descriptions).
There is always a temptation to “scrimp-and-save” a little on this aspect of petrographical studies, but this is the time where the real detail and intricacies of samples can be investigated and documented.
Modal analysis (point counting) data provides fundamental information on the composition of your samples, including:
Original detrital mineralogy.
Authigenic mineralogy.
Nature and abundances of macropores.
Data / results are presented in spreadsheet format, integrated onto individual sample descriptions and used extensively throughout our reports on various plots and diagrams. The phases differentiated during modal analysis are tailored on a project-by-project basis – and can be designed to be consistent with existing datasets for mature fields, or compliant with the inputs required for “Touchstone” modelling.
