Numerical simulation the effect of back rake angle PDC cutter on the rock fracture mechanism using discrete element method
Mohammad
Fatehi Marji
Department of Mining and Metallurgy, Engineering Faculty, Yazd University
author
Amirhossien
Mazrouie
Student of Mining Engineering of Yazd university
author
Mehdi
Najafi
Assistant Professor of Faculty of Mining and Metallurgy Engineering of Yazd university
author
Mohsen
Mohebi
Faculty of Mining and Metallurgy Engineering of Yazd university
author
Mohajer
Ebadi
Master of Planning for Drilling, National Iranian South Oilfields Company
author
text
article
2019
per
In the oil, construction and mining industry, different types of cutting tools using to extract rock materials. Hence, the investigation of the reaction of the cutting tool with the stone can be a suitable method for analyzing the problems associated with the failure occurred at the time of drilling. One of the factors affecting rock failure mechanism At the time of drilling Geometry of the cutting tool (cutter), Which has a significant impact on Mechanical specific energy (energy required to cut through a unit volume of rock). Numerical methods DEM One of the most advanced methods for modeling issues Which is accompanied by a strain and a deformation. The main goal of this research is rock cutting simulation and examining the effect of the bake rake angle on the cutter PDC performance On two samples of sedimentary rock (sand stone, limestone). The instrument used in this study numerical software particle flow code (PFC2D) which simulates the mechanical behavior of material using a distinct elemental method (DEM), Based on the results, limestone needs more Mechanical specific energy than sandstone, This can be due to more limestone resistance to sandstone. But increasing the back rake angle from 10 degrees to 40 degrees increases the Mechanical specific energy consumption. In fact, horizontal force cutting is a major factor affecting the amount of Mechanical specific energy. In addition, the results of the surveys show The mechanism of the flow of crushed material in front of the cutter blades Function of cutter geometry and the friction angle between the cutter and the crushed particles. and is one of the effective factors in the amount of Mechanical special energy.
Journal of Petroleum Geomechanics
Petroleum Geomechanics Association
2538-4651
2
v.
2
no.
2019
1
14
http://www.irpga-journal.ir/article_63110_e07b1b23f0576307cd90f2cd156e7adc.pdf
dx.doi.org/10.22107/jpg.2018.63110
An investigation of the effects of casing erosion and cement elastic modulus on the casing collapse phenomenon: a case study on an oil field in southwest Iran
Sajjad
Haghshenas Lari
Sharif University of Technology, Chemical and Petroleum Engineering Department, Tehran, IR Iran
author
Saeed
Shad
Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran
author
Alireza
Zangeneh Var
Mehran Engineering & Well Services Company, Tehran
author
text
article
2019
per
Casing collapse phenome during the production of boreholes drilled in high-pressurized reservoirs are a common challenge that the petroleum industry is facing universally. Such a problem has been observed 21 times in the boreholes drilled at one of the high-pressurized fields in Southwest Iran whose 56-production-well consequently reduced to 38 (by losing 18 producers due to the casing failure). Based on the studies conducted on the collapse phenomenon different factors contribute to the occurrence of such a problem. The important factors have been reviewed, analysed, and reported in the literature are: The stresses applied due to point-load on the wellbore and the casing by geomechanical and tectonic effects Casing erosion The presence of void spaces between the casing and the wellbore wall Casing type and quality Cement type and quality Pore pressure (related to Geomechanical effect?) The quality of cementing bondageIn the present study, taking advantage of ABAQUS, the efforts have been put to analyse and study the effects of the casing erosion and cement elastic modulus on the stress distribution around the borehole by simulating formation-cement-casing system considering in-situ stress. The cement displacement and the consequent stress tensor applied on the casing have been investigated. The numerical studies have been conducted in two cases considering the cement elastic modulus higher and lower than the formation elastic modulus. The results showed that the point-erosion of the casing has a stronger effect than that of the cement elastic modulus on the stress distribution around the borehole and the displacement of the surrounding cement.
Journal of Petroleum Geomechanics
Petroleum Geomechanics Association
2538-4651
2
v.
2
no.
2019
15
29
http://www.irpga-journal.ir/article_84093_c4e89fe9f77db8e85c8e51c6b662f3aa.pdf
dx.doi.org/10.22107/jpg.2019.135999.1063
Investigating the effect of pore pressure increase due to gas injection on the stability of normal faults in one of the SW Iranian oil fields
Mohammad
Ghafoori
Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
author
Majid
Taghipour
Geology Department, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
author
Gholam Reza
Lashkaripour
Department of Geology, Faculty of Science,
Ferdowsi University of Mashhad
Mashhad, Iran
author
Naser
Hafezi Moghaddas
Department of Geology, Faculty of Science,
Ferdowsi University of Mashhad, Mashhad, Iran
author
Abdollah
Molaghab
National Iranian South Oil Company, (NIOSC), Ahwaz, Iran
author
text
article
2019
per
Decreasing reservoir pressure caused by hydrocarbon exploitation is one of the major problems related to oil reservoirs. In order to maintain the current production rate the lost energy should be compensated. Gas injection is a common method for increasing reservoir pressure and is mainly used in SW Iranian oil fields. Reactivation of pre-existing faults is one of the potential risks related to gas injection. In this study, using the analytical method of modified slip tendency, the reactivation possibility of four faults in an SW Iranian oil field has been investigated, and the critical pore pressure is estimated. Results suggest that all the faults are stable in the current stress field, and F2 is the most stable fault that can undergo a maximum pore pressure of 57 MPa before reactivation. Results of fracture stability analysis show that the highest increase in horizontal stress needed for reactivation is for F2. This means that faults with an east-west strike are more stable than the faults with a north east-south west strike in the field.
Journal of Petroleum Geomechanics
Petroleum Geomechanics Association
2538-4651
2
v.
2
no.
2019
30
39
http://www.irpga-journal.ir/article_84094_22f4c6cb704b8b396fc860d8ccf68a4a.pdf
dx.doi.org/10.22107/jpg.2019.143304.1065
Upscaling of the geomechanics parameters of reservoir using the kernel function method with adaptive bandwidth and comparing with the results of wavelet transformation
Mohammad_Reza
Azad
Faculty of Mining, Petroleum & Geophysics Engineering, Shahrood University of Technology, Shahrood, Iran
author
Abolghase
Kamkar_Rouhani
Faculty of Mining, Petroleum & Geophysics Engineering, Shahrood university of technology, Shahrood, Iran
author
Mohammad
Arashi
Faculty of Mathematical Science, Statistics, Shahrood University of Technology, Shahrood, Iran
author
text
article
2019
per
In this paper we are used as two different approaches; wavelet transformation and adaptive bandwidth in kernel method in upscaling process of geomechanical parameters of the reservoir. Geomechanics in oil field have been investigated compressive strength parameters, Young's Moduli, Bulk Moduli and shear Moduli to determine the quality of reservoir and rock as well as the effect of rock resistance and stress on the behavior of formations as a result of oil activities. The geomechanical parameters of the reservoir rock are calculated using petrophysical logs such as acoustic and porosity log. Identifying uniform zones and classifying rock quality requires looking at geomechanical parameters along a well. Upscaling can be used to ease the use of this classifier. In the wavelet theory, after the analyze or the desired signal to the desired level, the upscaled signal will be obtained from the composition of the approximation section of the same level and the remaining samples of the coefficient of detail. This is the same as multiresolution upscaling. In upscaling using the bandwidth of the kernel function, the threshold or bandwidth is defined which is in fact a function of the geomechanical parameter variability. Adaptive bandwidth method can provide a good model upscaling of cells. In areas of high variability, by choosing optimal bandwidth, the cells remain fine, and vice versa, in areas with smooth changes, the number of cells will be merged more together. Comparison of the results of the two methods is observed. Under identical conditions, the upscaling error of the upscaled-optimized model with the kernel bandwidth method is about 1.4 wavelet transforms, and it is also possible that according to the probable error rate, depending on the threshold and appropriate bandwidth can be used to determine the number of upscaled block of the simulated model according to the computational time.
Journal of Petroleum Geomechanics
Petroleum Geomechanics Association
2538-4651
2
v.
2
no.
2019
40
54
http://www.irpga-journal.ir/article_84280_85cee5f272c7ca0f81738c2dfa241b9a.pdf
dx.doi.org/10.22107/jpg.2019.159974.1077
Impact of Salt Formation’s Geomechanical properties on the casing collapse event in oil wells using Numerical modeling
Mahdi
Bajoolvand
Tunneling and underground space engineering, Faculty of Mining Eng., Petroleum and Geophysics, Shahrood University of Technology, Shahrood, Iran
author
Ahmad
Ramezanzadeh
Assistant Professor; Faculty of Mining Eng., Petroleum and Geophysics, Shahrood University of Technology
author
text
article
2019
per
It is neccecery to use numerical methods in prediction the long-term behavior of structures with considering different conditions, because of presentation general and quick response of problems. Creep behavior of salt, as a time-dependent behavior, has always caused problems such as shear failure and convergence of oil wells casings. Thus, it is important to study of long-term behavior of these formations and the effect of creep behavior on well stability. In addition to time, salt layer thickness, stress distribution conditions and mechanical characteristic of salt rock are geomechanical factors which affecting on creep behavior of salt formations. Thus, in this paper, 3D numerical simulation using FLAC3D software is being performed to evaluate the effect of salt formation’s geomechanical properties (e.g. salt layer thickness, stress distribution and mechanical parameters of salt rock) on casing collapse of oil wells by considering data from one oil well in Kupal oilfield. For this purpose, at the first, Uniaxial creep test have been simulated similar to real conditions. Then by comparing between experimental and numerical results, constitutive model has been validated. Burgers creep model has been chosen as constitutive model for salt formation based on this validation. To be very close to real condition and also avoiding from simplifications as much as possible, Drilling rate, Drilling mud pressure, cement injection and casing installation have been considered in modeling. Then, three dimensional model has been solved for several period of time. Based on the results, stress distribution conditions have a major role in the creep behavior of salt formation among geomechanical properties. The effect of salt layer thickness on the amount of damage imposed to the casing is negligible. Also, studying the behavior of salt with different elastic modulus has shown that this parameter is an important factor to cause casing collapse of oil wells.
Journal of Petroleum Geomechanics
Petroleum Geomechanics Association
2538-4651
2
v.
2
no.
2019
55
68
http://www.irpga-journal.ir/article_63111_501e3d7f437372ed7c2808fe1636c168.pdf
dx.doi.org/10.22107/jpg.2018.104127.1046
Experimental Investigation of Iranian Quartz Sands for Proppant Production Used in Hydraulic Fracturing Operations
Saeid
Norouzi Apourvari
Department of Petroleum Engineering, Faculty of Engineering, Shahid Bahonar University of Kerman,Kerman, Iran
author
Mohammd Hosein
Vahidi Shahir
Department of Petroleum Engineering, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
author
Hossein
Jalalifar
Shahid Bahonar University of Kerman,Kerman,Iran
author
text
article
2019
per
Appropriate proppant selection is one the most important parameters for the success of hydraulic fracturing operations. In this study, the performance of proppants has been investigated in accordance with ISO and API standards. Sieve analysis, crush resistance, sphericity and roundness and bulk density were conducted for this purpose. 10 quarts sand mines, located in different parts of Iran, were considered as target sand resources in this study. From samples arrived, four quartz sand samples from three mines successfully passed the preliminary tests and selected for final experimental studies. The results showed that, Kerman 16/30 sand has potential for frac-sand application up to 4000Psi while Kerman 20/40 sand showed potential for frac-sand application up to 3000Psi. Malayer 20/40 sand showed no potential for use as proppant and Firoozkooh sand could be used as frac-sand only in formation with low closure pressure up to 1000Psi. Finally, the hydraulic conductivity and permeability of samples at different closure stresses were measured by an in-house conductivity cell and the results were consistent with the results of the initial tests.
Journal of Petroleum Geomechanics
Petroleum Geomechanics Association
2538-4651
2
v.
2
no.
2019
69
83
http://www.irpga-journal.ir/article_63113_8d71fc0fc82ea88d6eb473bec47888c4.pdf
dx.doi.org/10.22107/jpg.2018.63113
A Numerical Study of the Effect of Fluid Pressure on Smeared Cracking Behavior in the Caprock of Underground Gas Storage Reservoirs
Maysam
Rajabi
birjand university of technology
author
hossein
salari rad
Amir kabir university of technology
author
mohsen
masoudian
researcher in Australia
author
text
article
2019
per
The injection or extraction of gas can change the pore pressure within the reservoir, which in turn results in redistribution of the stress field. Consequently, the induced deformations within the reservoir and the sealing caprock can potentially prompt a damage zone in the caprock.The main objective of this paper is to develop a model to estimate the growth and extension of cracks in the caprock. In order to achieve this aim, the smeared crack approach is used to model the process of cracking in the caprock. To do this, we will employ smeared crack approach to study the initiation and propagation of cracks in caprock of subsurface reservoir. There are generally three approaches in solid mechanics when modelling cracks: discrete crack, interface elements and smeared crack. Although, discrete crack approach reflects the fracture development phenomenon most closely, it does not fit the nature of numerical methods and it can computationally expensive with development of cracks, each node is replaced by more nodes, which entails re-definition of finite element mesh and hence more computational resources are needed. On the other hand, smeared crack approach assumes that the cracked solid is a continuum and permits the description of the medium in terms of conventional stress-strain equations. Within the smeared crack framework, small cracks are formed in the band are gradually connected to each other and one or more cracks may be defined for each gauss point of each element. As one of the important innovations of this paper, the study of the effect of fluid pressure on the smeared crack propagation, has been done, which is based on coding in FORTRAN programming environment. Due to the results obtained by the flow of fluid into the crack, the crack opening increased significantly.
Journal of Petroleum Geomechanics
Petroleum Geomechanics Association
2538-4651
2
v.
2
no.
2019
84
105
http://www.irpga-journal.ir/article_86953_14669f4fd0955fa587c9068d3f321bef.pdf
dx.doi.org/10.22107/jpg.2019.173228.1087