Identifying Porosity Sweet Spots in an Eagle Ford Vertical and Lateral Well
Amplified Geochemical Imaging
A variety of logging technologies provide information during drilling as to the presence of hydrocarbons. However, these logging technologies do not measure hydrocarbons directly, but rather measure hydrocarbon proxies and infer hydrocarbon presence and phase based on this data. These technologies, while sophisticated can lack specificity and sensitivity when trying to accurately identify hydrocarbons.
Additionally, some new technologies can monitor hydrocarbons from n-C1 (methane) to n-C8 (octane) and expand the scope of hydrocarbon detection. These new technologies can clearly detect gas range organics and can infer light oils and condensates. However, all of these technologies lack the ability to measure the heart of the oil or liquid hydrocarbon finger-print of n-C7 (heptane) to n-C15 (pentadecane). Thus accurately characterizing and differentiating between multiple oil fingerprints becomes difficult, if not impossible, for current technologies. As such, these limitations negatively impact the ability of companies to properly assess and evaluate plays like the Eagleford that have numerous stacked liquid pays.
However, advances in well logging technology now provide the ability to analyze downhole cutting samples to directly characterize the composition of hydrocarbons vertically through the prospective section. This provides the unique ability to look at a broad compound range from C2 to C20, which is significantly more expansive than the limited traditional ranges of C1-C5 or C1-C8 of most well gas logging techniques. The result is the ability to not only characterize gas and condensate range hydrocarbons, but also characterization multiple liquid or oil phase hydrocarbons contained in the stratigraphic intervals.
The Amplified Geochemical Logging data was able to:
- Identify the most prolific hydrocarbon bearing zones
- Identify the areas of greatest porosity in both the vertical and lateral well
- Clearly distinguish between various hydrocarbon phases
- Distinguish multiple oil signatures
- Identify a zone with a high degree of water saturation
- Indicate where the lateral drilling was below or above the zone of interest
- Infer there were no seals between multiple zones
- Deduce thin shale seals that were not detected by well logs
AAPG Search and Discovery Article #90205 © AAPG Geoscience Technology Workshop, Permian and Midland Basin New Technologies, September 4-5, 2014, Houston, Texas