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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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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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