Investigation of Gravity Drainage in Fractured Porous Media Using Rectangular Macromodels

Zendehboudi, Sohrab; Mohammadzadeh, Omid; Chatzis, Ioannis

doi:10.2118/2008-138

Cited by 11 publications

(61 citation statements)

References 30 publications

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“…At a constant pumping rate, ΔH between the two G-L interface positions is observed to remain unchanged during each CGD trial; the same result has been found for FFGD experiments (Zendehboudi et al 2008). One can relate these cases by considering identical experimental prototypes in which the matrix block height is so large that one can neglect the threshold capillary height.…”

Section: Elevation Difference Between G-l Interface Positions Withinsupporting

confidence: 67%

“…Based on our understanding of the free fall gravity drainage (FFGD) process (Zendehboudi et al 2008) and preliminary tests, the following five parameters influencing the process were specified as variables: fracture aperture, matrix height, matrix permeability, well spacing, and fluid viscosity. The dependent variables are CPR, MPWR, RF, and vertical elevation difference (ΔH) between the G-L interface positions in the matrix and fractures during CGD.…”

Section: Design Of Experimentsmentioning

confidence: 99%

“…The resulting void space would then be occupied by the invading gas phase, which originally comes from either the associated gas cap or from the source of gas injection (Saidi et al 1979;Saidi 1983Saidi , 1974Ahmadi et al 1996;Aziz and Settari 1979;Da Sle and Guo 1990;Dean and Lo 1988;Paul and Zoback 2007;Quintard and Whittaker 1996a, b;Rossen and Shen 1989;Salimi and Bruining 2008). It is believed that the original oil held in place through the matrix, which contains the major portion of ultimate recovery as a result of considerable storativity of matrix, needs more time to be transmitted toward fractures compared to the time associated with fractures drainage (Tan and Firoozabadi 1995;Chatzis and Ayatollahi 1995;Dullien et al 1990;Kantzas et al 1988;Da Sle and Guo 1990;Zendehboudi et al 2008). Interaction of gravity and capillarity forces dictates this communication phenomenon (Trivedi and Babadagli 2008;Zhou and Blunt 1997;Zimmerman and Bodvarsson 1991;Schechter et al 1994;Tavassoli 2005a, b;Zendehboudi et al 2008).…”

Section: Introductionmentioning

confidence: 99%

“…It is believed that the original oil held in place through the matrix, which contains the major portion of ultimate recovery as a result of considerable storativity of matrix, needs more time to be transmitted toward fractures compared to the time associated with fractures drainage (Tan and Firoozabadi 1995;Chatzis and Ayatollahi 1995;Dullien et al 1990;Kantzas et al 1988;Da Sle and Guo 1990;Zendehboudi et al 2008). Interaction of gravity and capillarity forces dictates this communication phenomenon (Trivedi and Babadagli 2008;Zhou and Blunt 1997;Zimmerman and Bodvarsson 1991;Schechter et al 1994;Tavassoli 2005a, b;Zendehboudi et al 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Others have emphasized the understanding of single-phase flow through a single fracture with no liquid transfer from the matrix into the fracture (Barenblatt and Zheltov 1960;Granet et al 1988) and Hughes presented a detailed discussion of the experiments (Schechter and Guo 1996;Zendehboudi et al 2008). Most of the experimental gravity drainage studies in fractured media lack an explicit G-L interface velocity distribution, effect of production rate on RF at gas breakthrough condition, and contribution of communication rate between the matrix and fracture (Saidi et al 1979;Saidi 1983Saidi , 1974Ahmadi et al 1996;Aziz and Settari 1979;Warren and Root 1963; Barenblatt and Zheltov 1960;Barenblatt et al 1990; Barkve and Firoozabadi 1992;Firoozabadi and Markeset 1992).…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study of Controlled Gravity Drainage in Fractured Porous Media

Zendehboudi

Chatzis

2011

Journal of Canadian Petroleum Technology

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Oil production from a fractured reservoir with a gas cap and an oil zone usually takes place at a constant withdrawal rate until gas breakthrough; thereafter, the pumping rate is influenced by the presence of gas. Knowing the effect of pumping rate on production performance before gas breakthrough and selecting optimum pumping rates are necessary. In this paper, the concept of "critical production rate" (CPR) is introduced; it is the production rate at which a porous medium has a recovery factor (RF) equal to that for higher rates before gas enters into the production well, and is also the rate above which the difference between liquid levels in the fracture and matrix remains unchanged. One may use the CPR to choose a lower pumping rate to increase RF before gas breakthrough and to aid in understanding the physics of pumping from fractured media in real cases.Flow visualization experiments were performed using rectangular unconsolidated-packed models with two fractures on the sides. Sensitivity analyses were performed on the effects of different system parameters on the CPR, the maximum possible withdrawal rate (MPWR), RF at gas breakthrough, and gas-liquid (G-L) interface behaviour in both matrix and fractures. Results show that as long as the porous medium is drained with a constant liquid withdrawal rate below CPR, the height difference between G-L interfaces in the matrix and fracture remains constant. CPR and RF can also be related to other system parameters using dimensionless numbers, such as fracture/matrix permeability ratio and Bond number.

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Section: Elevation Difference Between G-l Interface Positions Withinsupporting

confidence: 67%

Section: Design Of Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Study of Controlled Gravity Drainage in Fractured Porous Media

Zendehboudi

Chatzis

2011

Journal of Canadian Petroleum Technology

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Quantifying the reimbibition effect on the performance of gas‐oil gravity drainage in fractured reservoirs: Mathematical modelling

Rahmati¹,

Rasaei

2019

Can J Chem Eng

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As a major oil production mechanism, gravity drainage in fractured oil reservoirs is heavily affected by the reimbibition phenomenon. In this work, a stack of oil-saturated two matrix blocks surrounded by oil-saturated fractures are considered as a synthetic fractured reservoir. A mathematical computer program is developed to numerically simulate the fluids' flow through the matrixes and fractures employing the finely gridded single porosity concept. Simulation results are validated by checking the continuity of the gas volume through the reservoir. The percentage of oil recovered by gravity drainage is determined employing the new material balance equation approach. A new procedure is employed for deactivating the reimbibition phenomenon, introducing the zero transmissibility for the oil phase in the case of oil transfer from the fracture to matrix region. According to the simulation results and considering the proposed model, under the constraints of constant gas injection and oil production rates, fully or partially deactivating the reimbibition phenomenon causes a faster gas movement through vertical fractures. The reason for this is that some of the oil leaving the upper matrix block goes to vertical fractures and causes a faster gas breakthrough in them due to reduced available pore volume to gas. In this case the oil recovered by gravity drainage from the system is decreased. Inactivating this phenomenon in the simulated case study causes a 40 % reduction in oil production by gravity drainage from the matrix blocks until the breakthrough time.

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Experimental investigation of secondary and tertiary oil recovery from fractured porous media

Maroufi

Ayatollahi

Rahmanifard

et al. 2013

J Petrol Explor Prod Technol

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Naturally fractured reservoirs (NFRs) contribute in large extent to oil and gas production to the ever increasing market demand of fossil energy. It is believed that the vertical displacement of oil during gas injection assisted by gravity drainage (GAGD) is one of the most efficient methods for oil recovery in these reservoirs. Hence, in this work, unconsolidated packed models of cylindrical geometry surrounded by fracture were utilized in order to perform a series of flow visualization experiments during which the contribution of different parameters such as the extent of matrix permeability, physical properties of oil (viscosity, density, and surface tension) and the withdrawal rate was studied. Furthermore, mutual effects of permeability, oil properties, and production rate on oil recovery efficiency through controlled and free fall gravity drainage processes were also investigated. Experimental results obtained from secondary and tertiary recovery experiments demonstrated that decreasing model permeability and increasing oil viscosity during secondary recovery process reduced the recovery efficiency for all production rates, while under tertiary recovery process these phenomena lead to more oil production for all production rates.

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Investigation of Gravity Drainage in Fractured Porous Media Using Rectangular Macromodels

Abstract: I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public.

Cited by 11 publications

References 30 publications

Experimental Study of Controlled Gravity Drainage in Fractured Porous Media

Experimental Study of Controlled Gravity Drainage in Fractured Porous Media

Quantifying the reimbibition effect on the performance of gas‐oil gravity drainage in fractured reservoirs: Mathematical modelling

Experimental investigation of secondary and tertiary oil recovery from fractured porous media

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