ALBERT

Description: The SEG Board of Directors has proposed replacing the article in SEG Bylaws that provides for indemnification of Society leaders, representatives, and staff with simpler language. A new Article XIV on indemnification would give SEG all indemnification powers available to it under Oklahoma law.

Description: In this episode, Josef Paffenholz discusses the next trillion-dollar business and how the SEG Advanced Modeling (SEAM) Corporation could play an essential role in its creation. Paffenholz highlights why the oil and gas sector represents the best source to tackle industrial-scale carbon storage, why he believes it is dangerous to link carbon storage to oil price, and how advanced simulations such as SEAM could ignite a trillion-dollar business. Hear the full episode at https://seg.org/podcast/post/12531 .

Description: Geoscientists have important roles in the management of the world's water at local, regional, national, and global scales. Geophysical information is critical to ensure that people have enough water for domestic, agricultural, industrial, and other needs. Given the current challenges of water management, it has never been more critical to promote awareness of water's place in earth system science. To encourage everyone to understand, conserve, and protect water, Earth Science Week 2021 will be held 10–16 October.

Description: Blizzards and Broken Grousers: A Year of Antarctic Glaciology, by Les R. Denham, ISBN 978-1-560-80377-5, 2020, SEG, 348 p. Geologic Fracture Mechanics, by Richard A. Schultz, ISBN 978-1-107-18999-7, 2019, Cambridge University Press, 608 p.

Description: Digital rocks are 3D image-based representations of pore-scale geometries that reside in virtual laboratories. High-resolution 3D images that capture microstructural details of the real rock are used to build a digital rock. The digital rock, which is a data-driven model, is used to simulate physical processes such as fluid flow, heat flow, electricity, and elastic deformation through basic laws of physics and numerical simulations. Unconventional reservoirs are chemically heterogeneous where the rock matrix is composed of inorganic minerals, and hydrocarbons are held in the pores of thermally matured organic matter, all of which vary spatially at the nanoscale. This nanoscale heterogeneity poses challenges in measuring the petrophysical properties of source rocks and interpreting the data with reference to the changing rock structure. Focused ion beam scanning electron microscopy is a powerful 3D imaging technique used to study source rock structure where significant micro- and nanoscale heterogeneity exists. Compared to conventional rocks, the imaging resolution required to image source rocks is much higher due to the nanoscale pores, while the field of view becomes smaller. Moreover, pore connectivity and resulting permeability are extremely low, making flow property computations much more challenging than in conventional rocks. Elastic properties of source rocks are significantly more anisotropic than those of conventional reservoirs. However, one advantage of unconventional rocks is that the soft organic matter can be captured at the same imaging resolution as the stiff inorganic matrix, making digital elasticity computations feasible. Physical measurement of kerogen elastic properties is difficult because of the tiny sample size. Digital rock physics provides a unique and powerful tool in the elastic characterization of kerogen.

Description: SEG continues to support students through the Scholarships program. Since 1956, almost US$11.3 million in SEG scholarships has been awarded to more than 3000 global undergraduate and graduate students studying geophysics or closely related fields.

Description: Forced-oscillation stress-strain laboratory measurements are increasingly employed to obtain elastic and viscoelastic properties of rocks at seismic frequencies. Yet these measurements are time-consuming and expensive, due in part to the use of metal or semiconductor strain gauges, which need to be glued to the sample. Such gauges are fragile, have relatively low sensitivity, and measure very local strain only so the measurements can be affected by a slight misalignment of the system assembly and local heterogeneity of the rock. The emergence of fiber-optic distributed acoustic sensing (DAS) technology provides an alternative means of measuring strain. Strain measurements with DAS involve winding an optical fiber around the sample multiple times and connecting it to a DAS recording unit. Pilot experiments performed using this setup on a range of rocks and materials show good agreement with strain gauge measurements. Advantages of DAS over strain gauges include much higher strain sensitivity (down to 10−11) and signal-to-noise ratio (and hence, shorter time required for measurements), larger dynamic range, ability to measure average (rather than local) strain in the sample, and robustness at elevated temperatures. Although the pilot experiments demonstrate the potential of DAS for rock physics measurements, further research and improvement of the proposed methodology are required to obtain independent estimates of Young's modulus and Poisson's ratio and to port the system into a pressure vessel to obtain rock properties under in-situ conditions.

Description: The Calendar chronologically lists professional events of interest to SEG members and means by which further information can be obtained.

Description: Microseismic events associated with shale reservoir hydraulic fracturing stimulation (HFS) are interpreted to be reactivations of ubiquitous natural fractures (NFs). Despite adoption of discrete fracture network (DFN) models, accounting for NFs in fluid flow within shale reservoirs has remained a challenge. For an explicit account of NFs, this study introduced the use of seismology-based relations linking seismic moment, moment magnitude, fault rupture area, and stress drop. Microseismic data from HFS monitoring of Marcellus Shale horizontal wells had been used to derive planar hydraulic fracture geometry and source properties. The former was integrated with associated well production data found to exhibit transient linear flow. Analytical solutions led to linear flow parameters (LFPs) and system permeability for scenarios depicting flow through infinite and finite conductivity hydraulic fractures. Published core plug permeability was stress-corrected for in-situ conditions to estimate average matrix permeability. For comparison, the burial and thermal history for the study area was used in 1D Darcy-based modeling of steady and episodic expulsion of petroleum to account for geologic timescale persistence of abnormal pore pressure. Both evaluations resulted in matrix permeability in the same picodarcy (pD) range. Coupled with LFPs, reactivated NF surface area for stochastic DFNs was estimated. Subsequently, the aforementioned seismology-based relations were used for determining average stress drops needed to estimate NF rupture area matching flow-based DFN surface areas. Stress drops, comparable to values for tectonic events, were excluded. One of the determined values matched stress drops for HFS operations in past and recent seismological studies. In addition, calculated changes in pore pressure matched estimates in the aforementioned studies. This study unlocked the full potential of microseismic data beyond extraction of planar geometry attributes and stimulated reservoir volume (SRV). Here, microseismic events were explicitly used in the quantitative account of NFs in fluid flow within shale reservoirs.

Description: The University of Naples Federico II SEG Student Chapter was recently awarded an SEG outreach grant. The grant enabled members of the student chapter to create a field experience titled “Neapolitan volcanism: First-hand experience on risks and resources,” which was held 13–14 May 2021 in Naples, Italy.