Case Study At-Surface Real-Time Isotope Logging Assesses Lateral Heterogeneity in Marcellus Shale
Thermal maturity calculation from isotope logging service provides insight into hydrocarbon fluid type in place.
Isotope Logging
Continuous δ13C–CH4 measurements in real time
Identify small-scale features
Gain early indication of reservoir connectivity
Enhance fluid typing
Isotope logging provides a completely new dataset, facilitating real-time, continuous geochemical characterization of hydrocarbons in the formation.
Geological and geochemical insights
- Isotope logging is a tool for the identification of reservoir connectivity and compartmentalization. It also provides the means for evaluating the sealing characteristics of caprocks and faults.
- δ13C–CH4 data provides information about encountered hydrocarbons and their origins, characteristics, and behavior in the subsurface. Because δ13C–CH4 ratios are related to hydrocarbon generation, they provide information about the hydrocarbon source rock, including its kerogen type and thermal maturity. This information can be used for correlating hydrocarbons with their source. The genetic information obtained from δ13C–CH4 ratios might provide information about a possible pay zone.
- In conjunction with the quantitative composition derived from the FLAIR real-time fluid logging and analysis service, isotope logging provides additional information about the similarity or dissimilarity of hydrocarbons encountered in the subsurface, useful for optimizing downhole sampling.
- In-reservoir processes—including biodegradation and water washing—alter the isotopic composition of methane. Isotope logging can be used to identify the presence of such processes and possibly their type and magnitude.
Greater depth resolution with less risk
Continuous, quality-controlled measurement of δ13C–CH4 significantly improves depth resolution and identifies small-scale features that would otherwise be missed. Data can be found in places where gas sampling is difficult or impossible. In addition, uncertainties and risks associated with collection, shipment, and analysis of samples are reduced or eliminated.
Integrated interpretation
The real-time integration of δ13C–CH4 ratios with data from other sources allows an immediate, more accurate interpretation of the geological and geochemical system, helping to optimize key decisions affecting the development of the reservoir.
The continuous isotope log places spot samples in context for geochemical interpretation. Identification of small features, removal of nonrepresentative samples, and prioritization of samples for rush analysis are part of a fast decision toolkit.
Geoservices is the industry leader in surface logging, focusing on drilling support and formation evaluation.
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