EBN’s HC Show Database: Correlating HC Shows with Structural Attributes (2018)

Dit internship rapport is geschreven door oud-stagiair Sabine Korevaar.

The Dutch subsurface represents a mature area for hydrocarbon exploration. In light of future exploration activities, research and geothermal projects, well -organized HC Show (HCS) data and integration of different data formats is highly valuable. HC Shows are already observed during the drilling and testing phase, but their value in follow-up exploration is often underutilized. Besides indirect hydrocarbon indications from wireline logging (resistivity), direct evidence of HC occurrence can generally be observed in mudlog-, core- and test data. These Direct Hydrocarbon Indicators (DHI) are rarely comprehensively accessible via the integrated platforms and are often provided in non-standardized data formats. To enable an easily accessible overview of HCS occurrence in the Dutch subsurface, EBN designed and developed the HC Show Database, whereas a sophisticated workflow al lows the integration of the different data formats. A well-structured classification approach ensures the analysis of each defined stratigraphic level along the borehole trajectory. Classification of encountered HCS and subsequent implementation via multiple visualization tools generates an overview of (potentially) mobile HC occurrence in the Dutch subsurface.

The HC Show Database is currently in a phase where its applicability to research can be tested. A significant amount of boreholes is analyzed and good coverage of the Dutch Northern Offshore is established. By employing different visualization techniques, extracted data from the HC Show Database can be used for specific research in the Upstream oil industry.

Alongside expansion of the dataset and refining and improving the workflow and visualization set-up, the main objective of this particular research is testing the applicability of the database in exploration. This is achieved by the means of an analysis of HC Shows from the Shal low Gas play. Indication for shallow gas presence in the subsurface is given by the occurrence of seismic amplitude anomalies. The gas saturation at these bright spot levels is considered one of the main key uncertainties, but actual statistics are lacking. With use of HC flow tests, being part of the HC Show Database, a semi-quantitative analysis is conducted to quantify the relation between amplitude anomalies vs. gas saturation. Eventually, shallow gas leads identified in the Dutch sector can be de-risked in terms of saturation by the statistics produced here.

Promising results from integrating other datatypes such as DHI’s demonstrate the value of the HCS database for exploration and research purposes. Therefore, EBN’s long-term aspiration is to roll out the HCS Database to its partners as a (interactive) visualization tool via an external Spotfire interface. Development of this new tool will be comparable to EBN’s GDE-Database tool and its release is currently expected by the end of 2018.