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gravity-drainage
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An experimental investigation of fracture tilt angle effects on frequency and stability of liquid bridges in fractured porous media
, Article Petroleum Science and Technology ; Volume 30, Issue 8 , Mar , 2012 , Pages 807-816 ; 10916466 (ISSN) ; Kharrat, R ; Ghazanfari, M. H ; Dejam, M ; Sharif University of Technology
Abstract
Liquid bridges are believed to play an important role in improving the recovery of fractured reservoirs. However, little is known about the stability of liquid bridges in fractured media at the pore scale. In this work, a glass micromodel representing a stack of two blocks was used at different tilt angles to monitor the frequency and stability of liquid bridges formed during free-fall gravity drainage as a function of tilt angle. It was observed that by increasing the tilt angle, the liquid bridge frequency decreased but its stability increased. This resulted in higher ultimate recovery. In addition, it was found that during the first half of the experiments, the number of bridges was...
Pore-Level Observation of Free Gravity Drainage of Oil in Fractured Porous Media
, Article Transport in Porous Media ; Volume 87, Issue 2 , 2011 , Pages 561-584 ; 01693913 (ISSN) ; Ghazanfari, M. H ; Kharrat, R ; Dejam, M ; Sharif University of Technology
2011
Abstract
This work presents results from two sets of experiments conducted to study, in pore level, the role of fracture aperture and tilt angle on the stability of liquid bridges and the shape of a front during free gravity drainage process. Glass micromodels of two different aperture sizes were used to monitor the mechanism of gravity drainage of air-crude oil system, rotating around a bottom corner to create different tilting angles. Oil content within the matrix blocks was determined as a function of time using a series of images obtained during the experiments, from which net drainage rate from the upper and lower matrix blocks is calculated. Liquid bridges are more frequent but less stable at...
Effects of rock permeability on capillary imbibition oil recovery from carbonate cores
, Article Scientia Iranica ; Volume 17, Issue 2 C , JULY-DECEMBER , 2010 , Pages 185-190 ; 10263098 (ISSN) ; Goodarznia, I ; Esmaeilzadeh, F ; Sharif University of Technology
2010
Abstract
In order to investigate the feasibility and effects of core permeability on capillary imbibition recoverable oil from carbonate cores, some laboratory tests were carried out at the EOR research laboratories of Sharif University, Iran. Outcrop rocks with different permeabilities were taken away from a recognized outcrop and used in these experiments. Special core analysis tests were run on two core samples to find out relative permeability and end point saturations. Wellhead separator oil and gas samples were collected and recombined to a reservoir gas - oil ratio. A core flooding system with a capability of free and forced imbibition testing was designed and installed. A number of free and...
Relationship between wetting properties and macroscale hydrodynamics during forced gravity drainage and secondary waterflood
, Article Petroleum Science and Technology ; Volume 28, Issue 8 , 2010 , Pages 804-815 ; 10916466 (ISSN) ; Kharrat, R ; Ghotbi, C ; Alipour Tabrizy, V ; Sharif University of Technology
Abstract
In order to relate the wetting properties at the pore scale to the macroscale prevailing forces, a series of experiments was performed in vertical porous media under forced gas invasion at various wettability conditions with partially spreading oil. To describe the dynamics of oil recovery in a three-phase flow condition, the downward gas flood experiments were continued by water injection from the bottom. Experimental results obtained in situations where the magnitudes of viscous, capillary, and gravity forces are comparable. We study the transition from flow configurations where the interface is stable with respect to viscous instability to flow configurations where viscous fingering...
Experimental and modelling study of gravity drainage in a three-block system
, Article Transport in Porous Media ; Volume 136, Issue 2 , 2021 , Pages 471-494 ; 01693913 (ISSN) ; Karimi Malekabadi, A ; Ghazanfari, M. H ; Rostami, B ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Gravity drainage is known as the controlling mechanism of oil recovery in naturally fractured reservoirs. The efficiency of this mechanism is controlled by block-to-block interactions through capillary continuity and/or reinfiltration processes. In this study, at first, several free-fall gravity drainage experiments were conducted on a well-designed three-block apparatus and the role of tilt angle, spacers’ permeability, wettability and effective contact area (representing a different status of the block-to-block interactions between matrix blocks) on the recovery efficiency were investigated. Then, an experimental-based numerical model of free-fall gravity drainage process was developed,...
Experimental investigation of tertiary oil gravity drainage in fractured porous media
, Article Special Topics and Reviews in Porous Media ; Volume 1, Issue 2 , 2010 , Pages 179-191 ; 21514798 (ISSN) ; Rostami, B ; Kharrat, R ; Ayatollahi, Sh ; Ghotbi, C ; Sharif University of Technology
2010
Abstract
The amount of residual oil trapped in the matrix of a fractured reservoir after water drive, either natural water drive or water injection, depends on the wettability of the matrix rocks. Gas oil gravity drainage (GOGD) has been proposed as the tertiary oil recovery process for this type of oil reservoir. The current work focuses on experimental investigation of tertiary GOGD in fractured porous media under different types of matrix wettability. Results of a set of experiments performed in artificial porous media composed of sand packs and glass beads of different wettability have been used to check the GOGD rate and the ultimate oil recovery for previously waterflooded models. A novel...
Evaluation of Liquid Bridge Behavior in the Presence of Flow Inside Fracture by Study of Viscosity, Fracture Width, Flow Rate, Wettability, and their Role on Fracture Capillary Pressure
, M.Sc. Thesis Sharif University of Technology ; Masihi, Mohsen (Supervisor)
Abstract
In fractured reservoirs under the gravity mechanism, the oil transfer between the matrix blocks is affected by mechanisms such as capillary continuity or re-imbibition. Capillary continuity between adjacent matrix blocks can be created by formation of liquid bridges, or physical contact of surfaces due to the roughness of the fracture wall surface.Since the presence of liquid bridges can be effective in creating capillary continuity and therefore the amount of oil production, the study of the presence of liquid bridges between matrix blocks and how they change in terms of volume and shape in the process of oil and gas movement is of particular importance. Although there are studies on the...
Estimation of naturally fractured oil reservoir properties using the material balance method
, Article Scientia Iranica ; Volume 21, Issue 3 , 2014 , Pages 781-791 ; ISSN: 10263098 ; Jamshidi, S ; Gholinezhad, S ; Sharif University of Technology
Abstract
In fractured reservoirs, a large variation of permeability due to the presence of fractures leads to changes in the production mechanism compared to conventional reservoirs. Hence, an appropriate model with the ability to describe the reservoir properly can provide a more confident prediction of its future performance. One of the features of a representative model is the number and height of the matrix blocks. The determination of these two parameters is one of the decisive steps in the calculation of an accurate amount of oil production from these reservoirs. In fact, matrix height shows its effect as a gravity force, which is one of the driving mechanisms. If the matrix height is less than...
Application of fast-SAGD in naturally fractured heavy oil reservoirs: A case study
, Article SPE Middle East Oil and Gas Show and Conference, MEOS, Proceedings, Manama ; Volume 3 , March , 2013 , Pages 1946-1953 ; 9781627482851 (ISBN) ; Hashemi Kiasari, H ; Alizadeh, N ; Mighani, S ; Kamari, A ; Baker Hughes ; Sharif University of Technology
2013
Abstract
Steam injection process has been considered for a long time as an effective method to exploit heavy oil resources. Over the last decades, Steam Assisted Gravity Drainage (SAGD) has been proved as one of the best steam injection methods for recovery of unconventional oil resources. Recently, Fast-SAGD, a modification of the SAGD process, makes use of additional single horizontal wells alongside the SAGD well pair to expand the steam chamber laterally. This method uses fewer wells and reduces the operational cost compared to a SAGD operation requiring paired parallel wells one above the other. The efficiency of this new method in naturally fractured reservoir is not well understood....
An experimental investigation of the effect of fracture dip angle on oil recovery and drainage rate in free fall gravity drainage in fractured reservoirs using a glass micromodel (A pore level investigation)
, Article Petroleum Science and Technology ; Volume 31, Issue 4 , 2013 , Pages 355-367 ; 10916466 (ISSN) ; Kharrat, R ; Ghazanfari, M ; Sharif University of Technology
2013
Abstract
Gravity drainage is the main production mechanism in the gas invaded zone in naturally fractured reservoirs. However, there are large ambiguities and complexities, resulting from the dynamic of oil depletion from matrix blocks toward the fracture network. Visualization of drained oil at pore scale using glass micromodels provides the opportunity to better understand the effects of different parameters which might affect oil recovery from fractured reservoirs. In this work a micromodel apparatus generated by laser etching is used to perform some gravity drainage tests on the network patterns. The experiments were performed on double block systems using crude oil. The block to block...
Investigation of the effect of geometrical properties of networked fractures on the efficiency of steam-assisted gravity drainage process
, Article Petroleum Science and Technology ; Volume 29, Issue 16 , Jul , 2011 , Pages 1625-1636 ; 10916466 (ISSN) ; Kharrat, R ; Vossoughi, S ; Sharif University of Technology
2011
Abstract
Various fracture geometrical properties such as orientation, extension, discontinuity, dispersion, location, and networking were investigated. Results indicate improved oil recovery and sweep efficiency in the presence of vertical fractures. Longer vertical fractures seemed to have even more beneficial effects. Horizontal fractures revealed detrimental effects on oil recovery and the performance became worse for longer horizontal fractures. Discontinuous horizontal fractures caused a better performance especially when combined with continuous vertical fractures (networking). Vertical fractures helped the growth of the steam chamber in the vertical direction, which resulted in higher oil...
A mathematical and experimental analysis of role of ultrasonic wave radiation on relative permeabilties in gravity drain
, Article 73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 ; Volume 7 , May , 2011 , Pages 5104-5108 ; 9781617829666 (ISBN) ; Keshavarzi, B ; Ghazanfari, M ; Ghotbi, C ; Amani, M ; Sharif University of Technology
Society of Petroleum Engineers
2011
Abstract
This work concerns with experimental and analytical investigation of role of ultrasonic wave radiation in relative permeability of both wetting and non-wetting phases in a free gravity drainage process in porous media under the influence of ultrasonic wave. Glass beads ranged from 70 to 100 mesh sizes were packed and used in the tests. The working fluids consist of distilled water, kerosene and Doroud and Paidar crude oils as wetting and air as non-wetting phase. The measured oil recovery data along with Hagoort (1984) backward methodology were used to determine and to compare the relative permeability of wetting phases in presence and absence of ultrasonic radiation. In addition, the...
Characterization of liquid bridge formed during gas-oil gravity drainage in fractured porous media
, Article 16th European Conference on the Mathematics of Oil Recovery, ECMOR 2018, 3 September 2018 through 6 September 2018 ; 2018 ; 9789462822603 (ISBN) ; Masihi, M ; Ghazanfari, M. H ; Shoushtari, A ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2018
Abstract
Gas-oil gravity drainage that takes place in the gas-invaded zone of fractured reservoirs is the main production mechanism of gas-cap drive fractured reservoirs as well as fractured reservoirs subjected to gas injection. Interaction of neighboring matrix blocks through reinfiltration and capillary continuity effects controls the efficiency of gravity drainage. Existence of capillary continuity between adjacent matrix block is likely to increase the ultimate recovery significantly. Liquid bridge formed in fractures has a significant role in maintaining the capillary continuity between two neighboring matrix blocks. The degree of capillary continuity is proportional to capillary pressure in...
A new semi-analytical modeling of steam-assisted gravity drainage in heavy oil reservoirs
, Article Journal of Petroleum Science and Engineering ; Volume 69, Issue 3-4 , 2009 , Pages 261-270 ; 09204105 (ISSN) ; Pishvaie, M. R ; Jabbari, H ; Sharif University of Technology
Abstract
Thermal recovery by steam injection has proven to be an effective means of recovering heavy oil. Forecasts of reservoir response to the application of steam are necessary before starting a steam drive project. Thermal numerical models are available to provide forecasts. However, these models are expensive and consume a great deal of computer time. An alternative to numerical modeling is to use a semi-analytical model. The objective of the current study was to investigate thermal applications of horizontal wells for displacement and gravity drainage processes using analytical modeling as well as reservoir simulation. The main novelties presented in the paper are: a) the transient temperature...
Simulation study of Steam Assisted Gravity Drainage (SAGD) in fractured systems
, Article Oil and Gas Science and Technology ; Volume 64, Issue 4 , 2009 , Pages 477-487 ; 12944475 (ISSN) ; Sharif University of Technology
2009
Abstract
The Steam Assisted Gravity Drainage (SAGD) process, a developed Enhanced Oil Recovery (EOR) process to recover oil and bitumen, has been studied theoretically and experimentally in conventional reservoirs and models and is found a promising EOR method for certain heavy oil reservoirs. In this work simulation studies of the SAGD process were made on different fractured models consisting of fractures in both Near Well Region (NWR) and Above Well Region (AWR) and even in the presence of networked fractures. At early stage of the SAGD process in fractured system, steam moves through the fractures first and then the matrix blocks are heated primarily by conduction and possibly some steam...
An exact analytical model for fluid flow through finite rock matrix block with special saturation function
, Article Journal of Hydrology ; Volume 577 , 2019 ; 00221694 (ISSN) ; Abbasi, M ; Ghazanfari, M. H ; Sharifi, M ; Kazemi, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
An exact analytical solution for one-dimensional fluid flow through rock matrix block is presented. The nonlinearity induced from flow functions makes the governing equations describing this mechanism difficult to be analytically solved. In this paper, an analytical solution to the infiltration problems considering non-linear relative permeability functions is presented for finite depth, despite its profound and fundamental importance. Elimination of the nonlinear terms in the equation, as a complex and tedious task, is done by applying several successive mathematical manipulations including: Hopf-Cole transformation to obtain a diffusive type PDE; an exponential type transformation to get a...
A mathematical analysis of the mechanism of ultrasonic induced fluid percolation in porous media: Part I
, Article Proceedings - SPE Annual Technical Conference and Exhibition, 20 September 2010 through 22 September 2010 ; Volume 7 , September , 2010 , Pages 5833-5856 ; 9781617389641 (ISBN) ; Sharif University of Technology
2010
Abstract
This work concerns with experimentally and analytically investigation of free gravity drainage process in porous media under the influence of ultrasonic wave radiation. Glass beads ranges from 70 to 100 mesh sizes were packed and used in the tests. The working fluids consist of distilled water, kerosene and Doroud and Paidar crude oils as wetting and air as non-wetting phase. The measured oil recovery data along with Hagoort (1984) backward methodology were used to determine and to compare the relative permeability of wetting phases in presence and absence of ultrasonic radiation. In addition the relative permeability of non-wetting phases for both cases were calculated from inverse modeling...