Greetings dear community,
Today, I have a question about reworked organic matter. In fact, I am actually working on a project in Frasnian hot shales with cutting/core samples in which I have to determine the maturity through microscopic observation.
We analysed samples of cores and cuttings from very close depths in the same well. These show show a similar trend, but with a clear contamination in the cutting samples coming most likely from cavings or poor cleaning prior to sampling. The Tmax in cuttings averages 439 in contrast to the 458-460°C in core samples.
This is further proven with HI values. For these samples, which are around 90% AOM and thus considered as type I organic matter (marine environment), the HI values for the cuttings (which are early mature) are quite low (150-170) whereas the values in the core samples (mature samples with a long due oil phase generation and close to dry gas) average 25-30 (type I OM produces its essential potential in the oil phase).
After determining that cutting samples are contaminated, my problem now is that I have reworked OM in my core samples. I can see it in my slides, but I lack some knowledge to do some quality identification and quantification of this reworked OM. for the plus side, this observation of mine correlates well with pyrolysis results (TOCs = 4-4.5% for S2s = 1.2-1.5 mg/g).
I need some references to read more about this subject. If anyone has some information on this, be it articles or books (or their own experience!!), it would be really helpful to me.
Best regards,
Yacine
Dear Yacine,
yes, it is correct, this problem is clear in cuttings and core samples.
I thin the organic petrology is one of the most important method to determine the mud additives or any new contamination within the sample.
One important point is washing and cleaning before Pyrolysis analysis , because mostly the different Tmax will affect by such added materials (i.e. non- indigenous). .
You can return to my publications on RG and you will find many papers useful for you.
all the best
Dear Ibrahim,
Thank you for your reply. Indeed, it is important to clean samples before any geochemical analysis. in our labs, we do it with DCM (after sorting to remove wood and other solid mud additives).
I will read your publications and look for any cases similar to mine.
Best regards
Slates are a separate issue. It is not submitted to the standard classification. I worked at Sonatrach and developed a scale of sedimentation using Tasmanites. They are well represented in all the deposits of Algeria.
Greetings Sergey,
I also like to focus on tasmanites because they are present in most samples.
However, my problem deals more with reworked organic matter, than cavings. This is hard to determine in Frasnian shales (which are AOM dominated) because it is hard to separed reworking from amorphisation of the original organic matter.
Most shales are formed in a non-oxygen medium. In the zone of serozarazheniya. This affects all chemical and physical processes of formation and transformation of petroleum matter. We study this in detail on the shales of Tatarstan. This has its own criteria.
- Badges
- Science topic
- Similar topics
- Linguistics
- Composition Studies
- Publications