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oa The Total Organic Carbon Estimation of Visean Organic Rich Formation with Limited Logging Dataset
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 17th International Conference Monitoring of Geological Processes and Ecological Condition of the Environment, Nov 2023, Volume 2023, p.1 - 5
Abstract
The Lower Visean organic rich formations in DDB are characterized by high TOC content and have specific signs in logging data. The main target formation Rudov bed is related to XIII Microfaunistic horizon and very representatively shows it. Carbonate platform in some wells in Glynsko-Solohivsky petroleum region also shows radioactivity increasing and it does not always correspond to clay. Naturally, the reservoirs and rock properties changes across the basin and not all geological and petrophysical instruments work very well in every case. For estimating TOC in cases with limited logging dataset DlogR approach is usually used, but it is does not work very accurately everywhere in DDB. In our investigations we have tried to compare several methods of TOC estimations and have proposed own equations for evaluation of TOC with limited logging data.
Our results show that separate equations for shale gas reservoirs has consistent better correlation with elemental spectroscopy data than the other methods. It looks very robust in case where we have limited logging dataset especially for old drilled wells. This equation can be applied not only in black shale reservoirs, but also in carbonate formations with organic rich layers, which aligns with SCAL analysis data.