Single Well Geochemical studies
The routine geochemical investigation of single well samples (or even outcrop samples) can usually be split into three main sub-categories: source rock identification, stain/show investigation and maturity assessment. For each of these, there are a number of geochemical techniques ranging from cheap and relatively inexpensive screening techniques through to more time consuming and expensive higher resolution analyses. Routine well studiess will typically start with a screening phase and dependent upon the initial result, a subsequent higher resolution programme will then be planned.
Data investigation and visualisation. A common problem of some databases is that once the data has been archived, it has a hard time trying to get back out. Efficient and user-friendly methods are needed to maximise work flow
Source rock identification starts with the initial screening of many samples by TOC. Sample selection will be on the basis of lithology, log characteristics and regional knowledge. Sufficiently rich samples are then characterised by Rock-Eval pyrolysis. Promising source rock samples can then be further characterised by PyGC and kerogen descriptions. Finally a handful of key samples can be submitted for extraction and higher resolution molecular and isotopic characterisation.
Stain and show indentification follows a similar step-wise programme. Sample selection is made on the basis of log characteristics and fluoresence. Whilst core material is preferable to ditch cuttings , show identification and characterisation can be performed on the latter. Depending upon specific study needs, screening starts with either Rock-Eval pyrolysis and/or Iatroscan screening for continuous reservoir sections. Based on initial results, suitably stained samples can be further characterise by either thermal extraction or total extract gas chromatography.
