Stress-based mathematical model for graded proppant injection in coal bed methane reservoirs
Alireza Keshavarz A , Kate Mobbs A , Aditya Khanna A and Pavel Bedrikovetsky AA The University of Adelaide
B presenter only
C Australian School of Petroleum
The APPEA Journal 53(1) 337-346 https://doi.org/10.1071/AJ12028
Published: 2013
Abstract
A technology called graded proppant (propping agent) injection that consists of the injection of proppant particles, with increasing sizes and decreasing concentrations, into a naturally fractured reservoir results in deeper percolation of the particles into the natural fracture system, and thus expansion of the stimulated reservoir area. The placement of graded proppant particles keeps the fractures open, even after pressure decline due to production. There is, therefore, an enhancement in the well productivity. This proposed technology could be used to improve the productivity of CSG wells and other unconventional resources; for example, in shales, tight gas, and geothermal reservoirs.
In this peer-reviewed paper, a mathematical model for well injectivity/productivity was developed for graded particle injection in a vertical well, lying at the centre of a circular drainage area. The model is based on an analytical solution of the quasi 1D problem of coupled axisymmetric fluid flow and geomechanics. Explicit analytical equations were derived for stress, and pressure and permeability distributions, as well as for the well index during injection and production. Results of previous computational fluid dynamic studies were used to determine the hydraulic resistance resulting from proppant plugging in the fractured system.
An optimal stimulation radius was identified, which resulted in the highest increment in the productivity index due to the application of graded proppant injection technology. The model was subsequently used for a sensitivity analysis using field data. The results showed that the productivity index increased more than four times by the application of this technology.
Alireza Keshavarz studied petroleum engineering at the Petroleum University of Technology (PUT) in Ahvaz, Iran for his first university degree. He continued his studies as a postgraduate student in hydrocarbon reservoir engineering at the University of Tehran and finished his Master’s degree in 2007. He worked for six years for the National Iranian Oil Company (NIOC) as a reservoir engineer. Alireza presently is a second-year PhD candidate, in petroleum engineering, at the University of Adelaide. alireza.keshavarz@adelaide.edu.au |
Kate Mobbs is an undergraduate student at the University of Adelaide, studying for her Bachelor of Engineering (Petroleum) and Bachelor of Engineering (Mechanical) degrees. She has worked on graded proppant injection technology for the past two years as part of her Honours projects across the School of Mechanical Engineering and the Australian School of Petroleum. kate.mobbs@student.adelaide.edu.au |
Aditya Khanna graduated with honours from the University of Adelaide with a Bachelor of Engineering (Mechanical)degree in 2011. Aditya is now a PhD candidate at the same institution. aditya.khanna@adelaide.edu.au |
Pavel Bedrikovetsky is a professor at the Australian School of Petroleum, University of Adelaide. He is also a senior staff consultant to Petrobras in the areas of formation damage, waterflooding, and improved oil recovery. During 1991–94, he was a visiting professor at the Delft University of Technology and at the Imperial College of Science and Technology. His main research interests include formation damage, suspension/colloid transport in porous media, and mathematical modelling of well stimulation and exploitation of unconventional energy resources. He is the author of two books about reservoir engineering and 150 technical papers published in international and SPE journals. He holds a BEng, an MSc (applied mathematics), a PhD (fluid mechanics), and a Doctor of Science (DSc) (reservoir engineering)—all from Moscow Gubkin Petroleum University. He served as section chairperson, short-course instructor, key speaker, and steering committee member at several SPE conferences, and was a 2008–09 SPE distinguished lecturer. pavel.bedrikovetsky@adelaide.edu.au |
