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Peak Particle Velocity for Blasting Rock Modeling - R. Yang & S. Green


New ARMA paper downloadable from OnePetro.

57th U.S. Rock Mechanics/Geomechanics Symposium (June 2023)

Blasting mechanisms are a complex coupling of the rock mass properties and the explosive detonation performance as well as the blast design parameters. Both rock mass and explosive properties have parameters that are inherently not well defined. Thus, blast modeling is greatly challenging to predict rock fragmentation, blast vibration, and the broken-rock mass movement. For blast modeling, previous work has shown that near-field signature-hole blast vibration monitoring is an effective method to obtain critical blast model input. In a blast field, multiple charges create nonlinear additive strains at a given point in the rock and time, which further complicates blast modeling. This paper shows how the measured peak particle velocity ("PPV") from the signature-hole blast vibration serves as a key controlling parameter for modelling. Using PPV as the controlling parameter, pressures and strains can be approximated at a point of interest. Rock breakage is then related by simplified approximations to the pressures and strains. The modelling method described in the paper relates all blast design parameters to the PPV induced by multiple charges at a point in the rock. Therefore, using PPV as a key parameter allows blasting models to simulate all blast design parameters and significantly simplifies blast modeling.

INTRODUCTION Predicting the results of rock blasting has been a long-standing challenge since its inception. However, the complex and dynamic mechanisms of rock blasting remain unclear (Fourney, 2015). The variables affecting the blast results are numerous, including rock mass properties, explosive properties, and blast design parameters. These variables interact in a nonlinear manner, making rock blast modeling more difficult than static or quasi-static rock mechanics modeling. If a blasting model is built purely based on the first principles of physics, it must involve many parameters related to rock properties and explosives. However, these parameters are often difficult to impossible to measure, which makes it challenging to obtain relevant blast modelling input. Moreover, most of these blast models cannot simulate full blasts and design parameters. Even a single modeling prediction requires a large amount of computing time and can only simulate a small number of blastholes. This forms a major impediment to the engineering applications of blast modelling. Researchgate.

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New pre-print paper: Potential and Challenges of Expanded Nuclear Energy

January, 2023

Nuclear fission reactors have long been part of the world energy supply, and provide about 2-percent of total annual world energy. The contribution as steam-produced grid electricity is about 10 percent of annual world electricity and over 20 percent of US annual grid electricity. This overview-summary speaks to the potential and challenges of much-expanded nuclear energy deployment.

America's first nuclear power plant - Shippingport, PA in 1958

Shippingport, PA. – May 1958

The potential and challenges for nuclear energy – for electricity and more broadly heat for industry – are considered in light of the worldwide energy transition that is focusing heavily on solar and wind primary energy sources to reduce greenhouse gas emissions. Nuclear energy – although less promoted in the on-going energy transition – has an opportunity to contribute much toward reducing emissions. Expanded nuclear energy is advocated by many, but often without complete consideration of the challenges that must be overcome to enable such expansion.

The overview-summary discusses the opportunities and challenges and draws on numerous previous publications and presentations, and most importantly on experience with nuclear technology. It seems clear that nuclear energy is a key part of the energy transition. Better public understanding based on facts can help to remove misconceptions and negative concerns and advance nuclear energy; nuclear energy is indeed important. Download paper here. 🌎

"Robe Talks": US Shale Oil/Gas Recovery: A Drastic Change is Required


April 3, 2020

Gang Han’s Hydraulic Fracturing Community (HFC) "Robe Talk" series kicked off this week. The purpose of his series is to keep technical professionals engaged and stimulated while most are staying at home. The first presentation was US Shale Oil/Gas Recovery: A Drastic Change is Required, by Sidney Green.

Read the pdf. (Click on slide numbers in red to move between presentation text and slides)

Webex hosted and presented by Dr. Gang Han, @ARAMCOServices, and ARMA.

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International Conference on Unconventional Geomechanics & Fall wrap up


October, 2019. We’ve been busy this fall! Sidney Green attended the US National Academy of Engineering annual meeting, presented a keynote at the 6th International Conference of Unconventional Geomechanics, and met with SINOPEC in Beijing. Bob and Jim spent time on triaxial testing services.

25th anniversary members - Members in attendance elected 25 years to the National Academy of Engineering (NAE).

25th anniversary members - Members in attendance elected 25 years to the National Academy of Engineering (NAE).

This year the National Academy of Engineering’s (NAE) annual meeting highlighted 50 years of space travel, from the Apollo days to present, listen here to the NAE human space flight webcast. Sidney currently sits on the NAE Committee of Membership.

Following the early October academy meeting, in mid-October, the China University of Mining and Technology, Beijing, hosted the 6th International Conference on Unconventional Geomechanics (UG6) 更多.

UG6 Attendees.

The focus of UG6 was on the recovery of minerals from stacked deposits. Sidney Green presented a keynote lecture on the Recovery of Fluids from Layered Reservoirs (you can find the presentation here). A great, informative conference …another of Professor Jishan Liu’s continuously growing symposium series.

While in Beijing, Sidney also presented at SINOPEC Research Institute of Petroleum Engineering (Sripe) on geothermal and deep hard-rock geomechanic strategies and developments. Sripe is an affiliate of Sinopec Group. It is a world leader for wellbore technique research and development - a center for state-of-the-art petroleum engineering techniques. It's always such a pleasure to have time with such an engaged audience. Thank you Sripe and CUMTB for inviting EPI to give timely lectures and for incredible hospitality.

Sidney Green & Baoping Zheng, Senior Engineer, The Research Institute of Petroleum Engineering, SINOPEC. This view from the SINOPEC petroleum offices of the Bird’s Nest stadium and the mountains in the distance -amazing.

Sidney Green & Baoping Zheng, Senior Engineer, The Research Institute of Petroleum Engineering, SINOPEC. This view from the SINOPEC petroleum offices of the Bird’s Nest stadium and the mountains in the distance -amazing.

A special thank you to Wei Wang for hosting and being a great tour guide in Beijing. Mr. Wang is a Ph.D. candidate at China University of Mining and Technology, Beijing (CUMTB).

A special thank you to Wei Wang for hosting and being a great tour guide in Beijing. Mr. Wang is a Ph.D. candidate at China University of Mining and Technology, Beijing (CUMTB).

 

Finally, Bob Griffin and Jim Marquardt continue their calibration and certification of in-vessel instruments for geomechanics tests.

A busy season!

Hope everyone is enjoying the end of fall!

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EPI technology update. Best wishes to our community for a happy and prosperous 2019 🌲


We continue focusing on research, engineering, and consulting-advising.

During 2018, EPI pursued improving the efficiency of hydraulic fracturing for the recovery of oil/gas from unconventional resources.

A technical presentation was given by Sidney Green at the 52nd US Rock Mechanics/ Geomechanics ARMA Symposium (www.epirecovery.com/news June, 2018) and an abstract has been submitted for presentation at ARMA 2019. Stay tuned for details.

 
Geothermal energy heating a pool, Iceland.

Geothermal energy heating a pool, Iceland.

Also during 2018, EPI continued development of the Geothermal Battery Energy Storage concept in collaboration with the Idaho National Laboratory and Prof. McLennan at the Univ. of Utah. Further funding for the concept is expected in early 2019 from the National Science Foundation via the Univ. of Utah with Co-Principal Investigators Prof. McLennan and Sidney Green.


EPI Presents on Cluster Spacing Effects at 52nd ARMA Conference in Seattle

June 1, 2018

”Early Time Fracture Growth and Cluster Spacing Effects” by S. Green, G. Xu, B. Forbes, J. McLennan, G. Green, D. Work is accepted for the ARMA Annual Symposium in Seattle.  Sidney Green will present the paper during the podium presentation, Tuesday June 19th, in the Technical Session track - Hydraulic Fracturing Geomechanics II.

ABSTRACT: The injection of large quantities of treating fluid and proppants during fracture stimulation of low permeability formations causes local insitu stress changes, sometimes referred to as stress shadowing or stress interference. Recent procedures for improving production have led to closer spacing of clusters, from approximately 80 feet spacing a few years ago to about 20 feet spacing now, or less in some cases. That is, there are now about four times the number of potential fracture initiation locations (clusters) per foot of lateral well, while the sand pumped per foot of lateral continues at about 1700-1800 pounds per foot. With four times the number of clusters and the same mass of sand pumped, the stress disturbance of one cluster to another cluster has changed. This paper addresses the near wellbore stress interference effects for close cluster spacing. Numerical simulations are presented using a robust linear-elastic 3-D hydraulic fracturing computer code that calculates fracture ‘bending’ and fracture width change due to stress interference. The stress interference that changes the fracture width is the most significant because the resistance to fracture fluid flow at high velocities in these narrow channels is the primary driver of stress shadowing fracture geometry changes. Continue..

🍂 Fall 2017 Updates


October, 2017

 
 

Zhaofeng Zhang, General Manager of CNPC GreatWall Drilling and Dr. GenSheng Li, VP of China University of Petroleum Beijing, and member of the Chinese Academy of Engineering and others visit EPI for geothermal energy discussions. 

China is pursuing significant research with the goal of increasing geothermal efficiency and the new concept of Geothermal Battery Energy Storage. China University of Petroleum and EPI agreed to pursue a joint drilling improvement cooperation, and an MOU is being developed.

New White Papers 

Meaningful fracture calculations... 

click to download full paper

click to download full paper

 

EPI and FrackOptima meet to discuss wellbore simulation analysis.

September, 2017

EPI brings in Dr. Alex Xu, developer and President of FrackOptima to present at the University of Utah, Energy & Geoscience Institute on the details of using simulation analysis software prior to in situ production....

EPI staff and Alex Xu.

EPI staff and Alex Xu.

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