The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Abbas Firoozabadi - One of the best experts on this subject based on the ideXlab platform.
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WETTABILITY ALTERATION OF POROUS MEDIA TO Gas-WETTING FOR IMPROVING PRODUCTIVITY AND INJECTIVITY IN Gas-LIQUID FLOWS
2003Co-Authors: Abbas FiroozabadiAbstract:Wettability alteration to intermediate Gas-wetting in porous media by treatment with FC-759, a fluoropolymer polymer, has been studied experimentally. Berea sandstone was used as the main rock sample in our work and its wettability before and after chemical treatment was studied at various temperatures from 25 to 93 C. We also studied recovery performance for both Gas/oil and oil/water systems for Berea sandstone before and after wettability alteration by chemical treatment. Our experimental study shows that chemical treatment with FC-759 can result in: (1) wettability alteration from strong liquid-wetting to stable intermediate Gas-wetting at room temperature and at elevated temperatures; (2) neutral wetting for Gas, oil, and water phases in two-phase flow; (3) significant increase in oil mobility for Gas/oil system; and (4) improved recovery behavior for both Gas/oil and oil/water systems. This work reveals a potential for field application for improved Gas-Well Deliverability and Well injectivity by altering the rock wettability around Wellbore in Gas condensate reservoirs from strong liquid-wetting to intermediate Gas-wetting.
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Wettability Alteration to Intermediate Gas-Wetting in Porous Media at Elevated Temperatures
Transport in Porous Media, 2003Co-Authors: Guo-qing Tang, Abbas FiroozabadiAbstract:Wettability alteration to intermediate Gas-wetting in porous media by treatment with FC-759, a fluorochemical polymer has been studied experimentally. Berea sandstone was used as the main rock sample in our work, and its wettability before and after chemical treatment was studied at various temperatures from 25 to 93°C. We also studied recovery performance for both Gas/oil and oil/water systems for Berea sandstone before and after wettability alteration by chemical treatment. Our experiment shows that chemical treatment with FC-759 can result in: (1) wettability alteration from strong liquid-wetting to stable intermediate Gas-wetting at room temperature and at elevated temperatures; (2) neutral wetting for Gas, oil, and water phases in two-phase flow; (3) significant increase in oil mobility for Gas/oil system; and (4) improved recovery behavior for both Gas/oil and oil/water systems. This work reveals a potential for field application for improved Gas-Well Deliverability and Well injectivity by altering the rock wettability around Wellbore in Gas condensate reservoirs from strong liquid-wetting to intermediate Gas-wetting.
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Phenomenological Modeling of Critical Condensate Saturation and Relative Permeabilities in Gas/Condensate Systems
Spe Journal, 2000Co-Authors: Kewen Li, Abbas FiroozabadiAbstract:Summary The effects of gravity, viscous forces, interfacial tension, and wettability on the critical condensate saturation and relative permeability of Gas condensate systems are studied using a phenomenological simple network model. The results from the simple model show that wettability significantly affects both critical condensate saturation and relative permeability. Relative permeability at some saturations may increase significantly as the contact angle is altered from 0° ~strongly liquid-wet! to 85° ~intermediately Gaswet!. The results suggest that Gas Well Deliverability in condensate reservoirs can be enhanced by wettability alteration near the Wellbore.
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FRACTURED PETROLEUM RESERVOIRS
1999Co-Authors: Abbas FiroozabadiAbstract:The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution Gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new Gas phase formation from in-situ process which can be significantly different from that of Gas displacement processes. The work is of experimental nature and clarifies several misconceptions in the literature. Based on experimental results, it is established that the main reason for high efficiency of solution Gas drive from heavy oil reservoirs is due to low Gas mobility. Chapter III presents the concept of the alteration of porous media wettability from liquid-wetting to intermediate Gas-wetting. The idea is novel and has not been introduced in the petroleum literature before. There are significant implications from such as proposal. The most direct application of intermediate Gas wetting is wettability alteration around the Wellbore. Such an alteration can significantly improve Well Deliverability in Gas condensate reservoirs where Gas Well Deliverability decreases below dewpoint pressure. Part I of Chapter III studies the effect of gravity, viscous forces, interfacial tension, and wettability on the critical condensate saturation and relative permeability of Gas condensate systems. A simple phenomenological network model is used for this study, The theoretical results reveal that wettability significantly affects both the critical Gas saturation and Gas relative permeability. Gas relative permeability may increase ten times as contact angle is altered from 0{sup o} (strongly liquid wet) to 85{sup o} (intermediate Gas-wetting). The results from the theoretical study motivated the experimental investigation described in Part II. In Part II we demonstrate that the wettability of porous media can be altered from liquid-wetting to Gas-wetting. This part describes our attempt to find appropriate chemicals for wettability alteration of various substrates including rock matrix. Chapter IV provides a comprehensive treatment of molecular, pressure, and thermal diffusion and convection in porous media Basic theoretical analysis is presented using irreversible thermodynamics.
H U Yongle - One of the best experts on this subject based on the ideXlab platform.
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low velocity non darcy Gas seepage model and productivity equations of low permeability water bearing Gas reservoirs
Natural Gas Geoscience, 2008Co-Authors: H U YongleAbstract:The flow behaviour of fluids in water-bearing Gas reservoirs was analyzed based on the experimental study of low-velocity non-Darcy percolation. Three kinds of mathematical models were established under the influences of movable water, inmovable water and combined water. Deliverability equations of Gas Well were obtained with the Gas slippage effect and the threshold pressure gradient existed respectively and simultaneously. The case study proved that the study was applicable and the corresponding equations could provide a necessary theoretical basis for defining reasonable Gas-Well Deliverability under different water conditions.
Dongming Zhang - One of the best experts on this subject based on the ideXlab platform.
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Permeability and Effective Stress in Dipping Gas Shale Formation With Bedding—Experimental Study
Journal of Energy Resources Technology-transactions of The Asme, 2020Co-Authors: Yufei Chen, Changbao Jiang, Guangzhi Yin, Andrew K. Wojtanowicz, Dongming ZhangAbstract:Abstract Shale Gas Well Deliverability and economics depend on extremely low permeability that is not only dependent on the rock bedding trend but also controlled by in situ stresses. The purpose of this study was to determine relative contributions of normal and tangential stresses with respect to the rock bedding plane on permeability evolution of shale. The study involved an analysis of the rock bedding structure, followed by triaxial testing of rock samples and theoretical modeling. Also simulated were the effects of stress-bedding and load cycling. The results showed shale permeability reduction during the stress loading process and its gradual recovery during the unloading process. Permeability change was more pronounced in response to normal stress but some effects of the tangential stresses were also observed. Moreover, a theoretical model was derived to describe permeability change with effective stress in the presence of normal and tangential stresses. The model was empirically matched with the experimental results. The assessment of relative contributions of normal and tangential stresses was quantified with the analysis of variance (ANOVA). The analysis revealed significance levels of normal stress, and two tangential stresses σt1 and σt2 on shale permeability as 81%, 5%, and 14%, respectively. An almost 20-percent contribution of tangential stress loading to permeability response indicates a need for the improvement in computing effective stress. Therefore, a new method was suggested to determine effective stress when predicting permeability evolution of shale.
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Triaxial Testing of Gas Shale Permeability Dependence on Heterogeneous Stress With Respect to Bedding
Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology, 2019Co-Authors: Yufei Chen, Changbao Jiang, Guangzhi Yin, Andrew K. Wojtanowicz, Dongming ZhangAbstract:Shale Gas has recently become the most promising source of unconventional hydrocarbon energy. Shale Gas Well Deliverability and economics depend on extremely low permeability that is not only dependent on the rock bedding trend but is also controlled by in-situ stresses. Thus, prediction of Well's Deliverability requires understanding permeability of a dipping shale with natural bedding under conditions of unequal stresses in-situ. The purpose of this study was to determine relative contributions of normal and tangential stresses with respect to the rock bedding plane on permeability evolution of Longmaxi shale in the Sichuan Basin, southwest China. The study involved an analysis of the rock bedding structure, followed with triaxial testing of rock samples and theoretical modeling. We used SEM observation to identify existence of microfractures and numerous inter-particle pores along the shale bedding planes that provide dominant pathways for Gas flow depending upon closing stress value. Stressdependent permeability was tested with a newly-developed multi-functional true triaxial geophysical (TTG) apparatus providing for a steady state Gas flow through the rock sample under conditions of normal stress and two unequal tangential stresses. Also simulated were the effects of stress-bedding and load cycling. The results showed shale permeability reduction during the stress loading process and its gradual recovery during the unloading process for both normal and tangential stress loading cycles. A hysteresis of the permeability response to cyclic loading was the largest when normal stress cycling was dominant. Moreover, permeability change was more pronounced in response to normal stress but some effects of the tangential stresses were also observed - particularly when the tangential stresses were dominant. A theoretical model was derived to describe permeability change with effective stress in the presence of normal and tangential stresses. The model was empirically matched with the experimental results. Assessment of relative contributions of normal and tangential stresses was quantified with the analysis of variance (ANOVA). The analysis revealed significance levels of normal stress, and two tangential stresses σt1 and σt2 on shale permeability as 81%, 5% and 14%, respectively, showing dominant effect of normal stress with clear contribution of tangential stresses. An almost 20-percent contribution of tangential stress loading to permeability response indicates a need for improvement in computing effective stress in permeability predictions of the Longmaxi shale. It also warrants testing other Gas shales to specifically determine the effect.
Liu Hua - One of the best experts on this subject based on the ideXlab platform.
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Study on differences of Gas Well test and production test of volcanic Gas reservoir
Oil Drilling & Production Technology, 2012Co-Authors: Liu HuaAbstract:Kelameili Gas field is the first packaged Gas field with developed reserves of more than 100 billion cubic meters in Xinjiang Oilfield.According to the geological features of strong heterogeneity,low porosity and low permeability,and complex water-Gas relationship,and the large difference of dynamic characteristics,the effect factors on Gas Well Deliverability were evaluated,based on the Well test and production test data of 15 Gas Wells.The differences of Gas Well test and production test of volcanic Gas reservoir were systematically analyzed based on the characteristics of Gas Well test and production test.It was believed that the initial Deliverability of volcanic Gas Wells had little relation with rate maintenance capability.The open flow capacity of production test is strongly related to the formation flow capacity,so it is better to predict the Gas Deliverability,and production test data should be fully used during Gas production allocation and plan adjustment.For fractured Wells,the Deliverability equation by Gas Well test is greatly different from production test data,and the main reason is the significant decrease of the conductivity with time,so the Deliverability prediction need consider the crack effect.
Gao Chao-li - One of the best experts on this subject based on the ideXlab platform.
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Gas Deliverability Model of Complex-shape Sandbodies with Small Reserve In Sulige Gasfield
Special Oil & Gas Reservoirs, 2012Co-Authors: Gao Chao-liAbstract:It is difficult to accurately predict Gas Well Deliverability of Sulige Gasfield because of its complex sand body shape,low controlled reserve of a single Well and rapid decline of formation pressure.Based on the study of characteristics of sand bodies of Sulige Gasfield,four superimposed sand models and a two-region permeable flow model are put forward.Dynamic Gas reserve and cumulative Gas reserve of near Well I Region and far Well II Region are calculated respectively by using material balance method of natural water drive and cumulative production,and therefore boundary formation pressure at different production time can be obtained by iteration.Further more,Gas Deliverability equation fit for complex shape sand bodies with small reserve of Sulige Gasfield is established with the combination of Gas Deliverability equation under pseudo steady state flow.The distribution characteristics of reservoir pressure complex shape sand bodies under different permeable flow modes and the rapid drop of formation pressure of Gas Wells in small reserve reservoirs are considered in the model.The practical application shows that the Deliverability calculated with the model is accurate and satisfactory and the error is within 10%.