First Appalachian Basin Geophysical Symposium
June 5th, 2019
Attending a convention, workshop or a symposium allows the attendees to mingle (with others who are probably from the same profession), learn (from the speakers and exhibits at these events) and share (if you are giving one or more talks/posters). For those engaged in staging such events, their organizational abilities are at display, and they gain new experiences and contacts. In short, such events are a win-win for everyone.
I was invited recently to attend and present at the First Appalachian Basin Geophysical Symposium held at Canonsburg, PA, on June 5, 2019. This one-day event was organized by the Geophysical Society of Pittsburgh (GSP) and themed ‘Sharing geophysical knowledge to maximize unconventional resource development of the Appalachian Basin’. The objective of organizing the event was to bring together many of the operators working in the Appalachian Basin, who are economically trying to develop reserves therein., by making use of different types of datasets, including geophysical data. Thus, the symposium lined up speakers who could share the technical challenges they faced and how they overcame them with their possible solutions.
The organizing committee comprised Scott Gorham from Seneca Resources, LLC, Casey Hagbo from Chevron and Randy Hunt from Range Resources. The symposium was organized at Noah’s Event Center at Canonsburg, a county 18 miles southwest of Pittsburgh. Whenever an event is organized at a venue away from most company offices, it helps the participants focus on the event, rather than get distracted or drawn into their daily official chores. All the talks were arranged in a large hall and the audio-visual system was good too, with a large projection screen.
The Symposium started at 8:15 am sharp with a short address by Joel Starr, the GSP President, followed by the ABGS Committee Chair, Scott Gorham, who requested the speakers to be mindful of the time allotted to them so that there is enough time for discussion after each talk. Interestingly, all speakers observed that request, and there were no lengthy drawn out talks. The following schedule was laid out for the talks:
Session I – Seismic Acquisition
- Geophysics and its Role in Appalachian Basin Oil and Gas Exploration and Development
- Key learnings from the Interstellar 3D suburban seismic shoot
- Nuisance Complaints and Damage Claims: The Role and Importance of Third-Party Consulting
Session II – Seismic Interpretation
4. Machine-learning analysis of multi-seismic attributes in the Pt. Pleasant
5. 3D Seismic Characterization of Devonian Transfer Faults in the Appalachian Plateau
6. Geophysical techniques for Marcellus development in Susquehanna County
7. The Unconventional Revolution in Exploration Geophysics – Is Machine Learning the Answer?
Session III – Seismic Interpretation/Processing
8. Reservoir scale imaging improvements from Pre-Stack Depth Migration (PSDM) and remaining sources of depth uncertainty associated with geophysical limitations and drilling measurements
9. New reprocessing technology and depth imaging leads to improved well planning and geosteering performance of the Marcellus Shale Formation in the Appalachian Basin
10. Bringing rigor to seismic reservoir characterization of Utica-Point Pleasant shale – a case study
Session IV – Well Based Applications
11. Active Seismic Source Imaging of the Pressurized Post Frac Rock Volume – ActivFrac
12. Fiber-Optic Microseismic Monitoring
13. Next Generation Distributed Acoustic Sensing (DAS) and its Implications for Hydraulic Fracture Monitoring
There were 81 participants at the Symposium. All talks were interesting and had some information or message in them.
Joel Starr from Peola Energy Resources, Pittsburgh, discussed the role of geophysics in the boom and bust cycles of hydrocarbon development in the Appalachian Basin over the last 50 years. This role has been significant in allowing for enhanced exploitation of the hydrocarbon resources in the area, starting from gravity, 2D seismic and leading up to the focus on shales, horizontal drilling and hydraulic fracturing, 3Dseismic along with microseismic and distributed acoustic sensing. This talk set the tone for the other talks of the day.
Ian Thomas from Huntley and Huntley Energy Exploration, Canonsburg, shared the company experiences while acquiring the Interstellar 3D seismic survey in southwest Pennsylvania. The seismic shoot was complicated by a number of factors, which were enunciated during the talk, and how the challenges that arose during the acquisition were resolved.
Benny Staudt from Vibro-Tech Engineers, Hazelton, Pennsylvania, drew attention to the fact that land owners on whose property the seismic data are shot can complain any time. Such complaints have the potential to become damage allegations, which should be avoided. Showing real world examples, the speaker explained how the third-party consultants hired by the oil and gas industry help ease such concerns or complaints by gathering technical data and help with compliance as required by municipalities in many areas.
Randall Hunt from Range Resources, Canonsburg discussed the application of machine learning analysis of multiattributes to help extract signatures that help interpret potential deep karsting in the Trenton Black River play, which in turn appears to have impacted the overlying Utica/Point Pleasant production in southwest Pennsylvania.
Travis Duran from Senerca Resources, Pittsburgh brought up an interesting observation about transfer faults causing an operational and productive risk for horizontal shale wells drilled in the Marcellus, and how 3D seismic was used to identify and characterize them. Transfer faults mentioned here refer to strike slip faults that transfer displacement from one fault to another.
Samuel D. Ely from Cabot Oil and Gas Corp., Pittsburgh, described the application of the 3D seismic attributes to define and visualize elusive structural features such as subsurface lineaments which may contribute to the production of hydrocarbons or create drilling hazards or both. Examples were cited from between the Upper Devonian Genesee Formation and the base of the Silurian Salina Salt, about the Genesee Formation and the Paleozoic section beneath Susquehanna County, Pennsylvania.
The keynote talk, by SEG Past President, Nancy House, referred to geophysics being an accepted early development tool of successful oil and gas companies, as well as the fact that microseismic mapping had made completion more efficient and safer. Besides the large number of seismic attributes generated from 3D seismic data are being used, possibly integrated by using machine learning tools to identify the highest production areas and their development.
After lunch, Casey Hagbo from Chevron drew attention to the fact that had used 2D and 3D prestack time migrated (PSTM) seismic data (acquisition and processing carried out 5 years ago) in the Marcellus shale area for well planning and assessing structural risks, prior to drilling with mixed results. Small scale structures were poorly imaged, and there were significant discrepancies in phase, frequency, amplitude, signal-to-noise ratio, and reflector timing due to differences in the velocity models between the three 3D PSTMs that Chevron had licensed and/or acquired. These discrepancies created uncertainty in the depth prognoses and degraded the quality of area-wide interpretation and modeling efforts. Later all three legacy surveys were merged and put through prestack depth migration (PSDM), which yielded depth imaging products that had improved signal-to-noise ratio, event continuity, amplitude and phase consistency, resolution, and better matched the interpreted geometry and lithology from drilled horizontal wells. Even after drilling several wells till date using the improved 3D PSDM, there are still limitations of geophysical data and models as well as uncertainty in directional drilling measurements. The utility and accuracy of directional drilling measurements could be pushed further by doing careful interpretation, seismic data QC and an understanding of the accuracy of directional drilling measurements.
The previous talk was followed by the next talk by Kim Sim Lee from InDepth Geophysical that performed the PSDM on Chevron’s legacy data and referred to in the previous talk. He elaborated on the workflow that was followed for doing so.
The next talk by Satinder Chopra from TGS, Calgary, discussed the inadequacy of using the available brittleness measures for characterizing Utica/Point Pleasant shales, and went on to briefly describe new attributes that make use of strain energy density and fracture toughness. While the former controls fracture initiation, the propagation of fractures is governed by the latter. As hydraulic fracturing comprises both these properties, we firmly believe that the proposed new attribute could be used to highlight the favorable intervals for fracturing.
After the coffee break, Alan Leaver, from Repsol, Warrendale, PA described the ActivFrac2018 experiment that was conducted in a lateral well with the intent of mapping fracture height and width by analyzing the birefringence of shear waves. Approximately 1000, 3C geophones were planted on the surface and three different types of Vibroseis sources were used in a process carried out before the fracing was done in the well, after it was done and a year after the fracing and start of production. Microseismic data was acquired during the actual fracing. The experiment demonstrated that it may be possible to map the base of the pressurized rock volume. These results were correlated with information derived from microseismic data as well as 3D surface seismic data.
Next Julian Drew from Sigma Cubed Microseismic, Houston described the use of fiber optics in the form of distributed temperature sensing and distributed acoustic sensing (DAS) during long term permanent monitoring of unconventional completions. Some challenges in the application of DAS for microseismic were discussed along with its limitations.
This talk was followed with another one on DAS given by Werner Heigl, who discussed the recent advances in DAS that have the potential to revolutionize hydraulic fracture monitoring and vertical seismic profiling. With the deployment of engineered optical fibers, the number of microseismic events detected per stage is of the order of thousands. Besides, optical fibers may no longer be installed behind casing for acquiring good quality data. Rather, engineered fibers can be integrated into the conventional wirelines and deployed inside a cased hole and horizontal wells.
The thirteen talks delivered at the event were enough to whet the appetite of the participants. The happy hour that followed the talks provided yet another opportunity for networking and chatting, with speakers and attendees all gathered together. It was a day well spent, lots to learn and assimilate, as well as making contacts.
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