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Vinicius Perrud Grothe - One of the best experts on this subject based on the ideXlab platform.
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Estudo da filtração de fluidos reticulados em simulações fisicas de fraturamento hidraulico
2017Co-Authors: Vinicius Perrud GrotheAbstract:Resumo: A perda de fluido por filtração é um dos aspectos fundamentais no projeto e na execução de operações de fraturamento hidráulico. Este trabalho teve como objetivos: o estudo da filtração associada à propagação de fraturas hidráulicas geradas em laboratório; e a comparação entre dois métodos para a determinação de coeficientes de filtração (análises de NoIte e de curvas de volume de filtrado vs. tempo). Foram utilizados corpos de prova de rocha sintética e géis reticulados com diferentes concentrações de polímero. O simulador fisico é constituído por uma estrutura de reação projetada para corpos de prova cúbicos (lOxlOxIO) cm3, os quais foram submetidos a um estado tridimensional de tensões. Foram usadas diferentes vazões de injeção com o objetivo de investigar o efeito do cisalhamento sobre o coeficiente global de filtração. Foram geradas fraturas radiais horizontais com diâmetros próximos, recorrendo-se ao controle do tempo de propagação. Coeficientes de filtração obtidos via análise de Noite foram comparados com coeficientes provenientes de células de filtração estática, considerando-se condições experimentais similares. Os resultados foram discutidos, concluindo-se que a simulação fisica de fraturamento constitui uma ferramenta útil para a avaliação da eficiência de fluidos e que também pode fornecer estimativas de coeficientes de filtração. A metodologia utilizada no trabalho consistiu numa técnica relativamente simples para a comparação da eficiência de diferentes géis de fraturamentoAbstract: The fluid loss plays an important role in the design and placement of hydraulic fracturing treatments. The main objectives of this work were: the study of the fluid loss associated with the propagation of hydraulic fractures generated at laboratory; and the comparison of two distinct methods for estimating leakoff coefficients (NoIte analysis and the filtrate volume vs. square root oftime plot). Synthetic rock samples were used as well as crosslinked fluids in different polymer concentrations. The physical simulations comprised the confinement of cubic rock samples, (10x10xl0) cm3, in a load cell for the application of an in Situ Stress Field. Different flow rates were employed in order to investigate shear effects on the overallleakoff coefficient. Horizontal radial fractures were hydraulically induced with approximate diameters, what was accomplished by controlling the injection time. Overall leakoff coefficients determined by means of NoIte analysis were compared to coefficients obtained from static filtration tests, considering similar experimental conditions. The research results indicated that the physical simulation of hydraulic fracturing may be regarded as an useful tool for evaluating the efficiency of fracturing fluids and that it can supply reliable estimates of fluid loss coefficients. The experimental methodology applied in this work turned out to be a considerably simple technique which allowed comparisons of fracturing gels pursuing different leakoff propertie
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Estudo da filtração de fluidos reticulados em simulações fisicas de fraturamento hidraulico
Universidade Estadual de Campinas. Faculdade de Engenharia Mecânica e Instituto de Geociências, 2000Co-Authors: Vinicius Perrud GrotheAbstract:A perda de fluido por filtração é um dos aspectos fundamentais no projeto e na execução de operações de fraturamento hidráulico. Este trabalho teve como objetivos: o estudo da filtração associada à propagação de fraturas hidráulicas geradas em laboratório; e a comparação entre dois métodos para a determinação de coeficientes de filtração (análises de NoIte e de curvas de volume de filtrado vs. tempo). Foram utilizados corpos de prova de rocha sintética e géis reticulados com diferentes concentrações de polímero. O simulador fisico é constituído por uma estrutura de reação projetada para corpos de prova cúbicos (lOxlOxIO) cm3, os quais foram submetidos a um estado tridimensional de tensões. Foram usadas diferentes vazões de injeção com o objetivo de investigar o efeito do cisalhamento sobre o coeficiente global de filtração. Foram geradas fraturas radiais horizontais com diâmetros próximos, recorrendo-se ao controle do tempo de propagação. Coeficientes de filtração obtidos via análise de Noite foram comparados com coeficientes provenientes de células de filtração estática, considerando-se condições experimentais similares. Os resultados foram discutidos, concluindo-se que a simulação fisica de fraturamento constitui uma ferramenta útil para a avaliação da eficiência de fluidos e que também pode fornecer estimativas de coeficientes de filtração. A metodologia utilizada no trabalho consistiu numa técnica relativamente simples para a comparação da eficiência de diferentes géis de fraturamentoThe fluid loss plays an important role in the design and placement of hydraulic fracturing treatments. The main objectives of this work were: the study of the fluid loss associated with the propagation of hydraulic fractures generated at laboratory; and the comparison of two distinct methods for estimating leakoff coefficients (NoIte analysis and the filtrate volume vs. square root oftime plot). Synthetic rock samples were used as well as crosslinked fluids in different polymer concentrations. The physical simulations comprised the confinement of cubic rock samples, (10x10xl0) cm3, in a load cell for the application of an in Situ Stress Field. Different flow rates were employed in order to investigate shear effects on the overallleakoff coefficient. Horizontal radial fractures were hydraulically induced with approximate diameters, what was accomplished by controlling the injection time. Overall leakoff coefficients determined by means of NoIte analysis were compared to coefficients obtained from static filtration tests, considering similar experimental conditions. The research results indicated that the physical simulation of hydraulic fracturing may be regarded as an useful tool for evaluating the efficiency of fracturing fluids and that it can supply reliable estimates of fluid loss coefficients. The experimental methodology applied in this work turned out to be a considerably simple technique which allowed comparisons of fracturing gels pursuing different leakoff propertie
Geoff Wang - One of the best experts on this subject based on the ideXlab platform.
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the present day in Situ Stress Field within coalbed methane reservoirs yuwang block laochang basin south china
Marine and Petroleum Geology, 2019Co-Authors: O Jiang, Geoff WangAbstract:Abstract Understanding in-Situ Stress variation is extremely important for coalbed methane (CBM) exploration and development; however, precise information on the present-day in-Situ Stress Field in the Yuwang Block of Laochang Basin is unclear. In the present study, the horizontal maximum (SHmax) and minimum (Shmin) principal Stress, and vertical Stress (Sv) in coal seams of Yuwang Block were systematically analyzed based on measured injection/falloff data and geomechanical models. The results indicated that, in the Yuwang Block, vertically, shallow coal seams (less than 800 m below ground level, bgl) mainly experienced the strike-slip faulting Stress regime (SHmax > Sv > Shmin); whereas deep layers (more than 800 m bgl) were characterized by the dominant normal faulting Stress regime (Sv > SHmax > Shmin). Laterally, with the No.9 coal seam case study, relatively lower Stress magnitudes were mainly located around Yuwang and Well L-4 regions. Coal permeability obtained from injection-falloff well tests decreased exponentially with the increased effective Stress, suggesting that coal permeability in the Yuwang Block was in-Situ Stress controlled. In addition, differential Stress and presence of natural fractures within coal seams significantly affected the geometry and pattern of hydraulic fractures. In coal seams of Yuwang Block, the present-day in-Situ Stress Field contributed to generate complex hydraulic fracture networks. The study results provided geological references for CBM development in the Yuwang Block of Laochang Basin.
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in Situ Stress Field in the fz block of qinshui basin china implications for the permeability and coalbed methane production
Journal of Petroleum Science and Engineering, 2018Co-Authors: Jia She, Yanhui Yang, Chunli Yang, Geoff WangAbstract:Abstract In Situ Stress affects reservoir permeability and stimulation, and thus coalbed methane (CBM) recovery. In this study, the in Situ Stress Field measured from 238 CBM wells in the FZ Block of Qinshui Basin, China, was investigated. The vertical Stress, horizontal maximum and minimum principal Stress are 5.92–20.08 MPa, 8.03–41.75 MPa, and 5.38–21.24 MPa, respectively. The in Situ Stress magnitudes increase with burial depth of the coal seams. The FZ Block is dominated by reverse and strike-slip faulting Stress regimes. Most of reverse fault Stress regimes appear within burial depth less than 500 m, whereas normal and strike faulting Stress regimes are deeper than 500 m. The relation between the coefficient of lateral Stress and burial depth shows that shallow strata are characterized by horizontal Stresses, whereas deep strata are generally hydrostatic pressures that approximately equal to the principal Stresses. Low gas and high water production are associated with vertical hydraulic fractures, wherein the horizontal minimum principal Stress is the minimum Stress. High gas and low water production are associated with horizontal hydraulic fractures, wherein the vertical Stress is the minimum Stress. This results are attributed to the enhanced permeability of the coal seam and the communication with overlying or underlying aquifers because the minimum Stress varies between vertical and horizontal minimum Stress. The orientation of the horizontal maximum principal Stress is ∼NEE–NE and is locally distorted by faults, which can be used to optimize the drilling, completion, and stimulation of CBM wells in the study area.
Grothe, Vinicius Perrud - One of the best experts on this subject based on the ideXlab platform.
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Estudo da filtração de fluidos reticulados em simulações fisicas de fraturamento hidraulico
[s.n.], 2019Co-Authors: Grothe, Vinicius PerrudAbstract:Orientador: Paulo Roberto RibeiroDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecanicaResumo: A perda de fluido por filtração é um dos aspectos fundamentais no projeto e na execução de operações de fraturamento hidráulico. Este trabalho teve como objetivos: o estudo da filtração associada à propagação de fraturas hidráulicas geradas em laboratório; e a comparação entre dois métodos para a determinação de coeficientes de filtração (análises de NoIte e de curvas de volume de filtrado vs. tempo). Foram utilizados corpos de prova de rocha sintética e géis reticulados com diferentes concentrações de polímero. O simulador fisico é constituído por uma estrutura de reação projetada para corpos de prova cúbicos (lOxlOxIO) cm3, os quais foram submetidos a um estado tridimensional de tensões. Foram usadas diferentes vazões de injeção com o objetivo de investigar o efeito do cisalhamento sobre o coeficiente global de filtração. Foram geradas fraturas radiais horizontais com diâmetros próximos, recorrendo-se ao controle do tempo de propagação. Coeficientes de filtração obtidos via análise de Noite foram comparados com coeficientes provenientes de células de filtração estática, considerando-se condições experimentais similares. Os resultados foram discutidos, concluindo-se que a simulação fisica de fraturamento constitui uma ferramenta útil para a avaliação da eficiência de fluidos e que também pode fornecer estimativas de coeficientes de filtração. A metodologia utilizada no trabalho consistiu numa técnica relativamente simples para a comparação da eficiência de diferentes géis de fraturamentoAbstract: The fluid loss plays an important role in the design and placement of hydraulic fracturing treatments. The main objectives of this work were: the study of the fluid loss associated with the propagation of hydraulic fractures generated at laboratory; and the comparison of two distinct methods for estimating leakoff coefficients (NoIte analysis and the filtrate volume vs. square root oftime plot). Synthetic rock samples were used as well as crosslinked fluids in different polymer concentrations. The physical simulations comprised the confinement of cubic rock samples, (10x10xl0) cm3, in a load cell for the application of an in Situ Stress Field. Different flow rates were employed in order to investigate shear effects on the overallleakoff coefficient. Horizontal radial fractures were hydraulically induced with approximate diameters, what was accomplished by controlling the injection time. Overall leakoff coefficients determined by means of NoIte analysis were compared to coefficients obtained from static filtration tests, considering similar experimental conditions. The research results indicated that the physical simulation of hydraulic fracturing may be regarded as an useful tool for evaluating the efficiency of fracturing fluids and that it can supply reliable estimates of fluid loss coefficients. The experimental methodology applied in this work turned out to be a considerably simple technique which allowed comparisons of fracturing gels pursuing different leakoff propertiesMestradoMestre em Engenharia de Petróle
Gunter Zimmermann - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation on Stress shadowing in fluid injection induced fracture propagation in naturally fractured geothermal reservoirs
Rock Mechanics and Rock Engineering, 2015Co-Authors: Jeoung Seok Yoon, Gunter Zimmermann, Arno ZangAbstract:In low permeability shale reservoirs, multi-stage hydraulic fracturing is largely used to increase the productivity by enlarging the stimulated rock volume. Hydraulic fracture created alters the Stress Field around it, and affects the subsequent fractures by the change of the Stress Field, in particular, mostly increased minimum principal Stress at the area of subsequent fracturing. This is called Stress shadow which accumulates as the fracturing stages advance from toe to heel. Hydraulic fractures generated in such altered Stress Field are shorter and compact with orientation deviating significantly from the far-Field maximum horizontal Stress orientation. This paper presents 2D discrete element-based numerical modeling of multi-stage hydraulic fracturing in a naturally fractured reservoir and investigates Stress shadowing. The Stress shadowing is tested with two different injection scenarios: constant and cyclic rate injections. The results show that cyclic injection tends to lower the effect of Stress shadow as well as mitigates the magnitude of the induced seismicity. Another modeling case is presented to show how the Stress shadow can be utilized to optimize a hydraulic fracture network in application to Gros Schonebeck geothermal reservoir, rather than being mitigated. The modeling demonstrated that the Stress shadow is successfully utilized for optimizing the geothermal heat exchanger by altering the initial in Situ Stress Field from highly anisotropic to less or even to isotropic.
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slip tendency analysis fault reactivation potential and induced seismicity in a deep geothermal reservoir
Journal of Structural Geology, 2009Co-Authors: I. Moeck, Grzegorz Kwiatek, Gunter ZimmermannAbstract:Abstract A slip tendency analysis is used to assess the reactivation potential of shear and dilational fractures in a deep geothermal reservoir in the Northeast German Basin, based on the notion that slip on faults is controlled by the ratio of shear to normal Stress acting on the plane of weakness in the in Situ Stress Field. The reservoir rocks, composed of Lower Permian sandstones and volcanics, were stimulated by hydraulic fracturing. A surprisingly low microseismic activity was recorded with moment magnitudes MW ranging from −1.0 to −1.8. The slip tendency analysis suggests a critically Stressed reservoir exists in the sandstones, whereas the volcanic rocks are less Stressed. Rock failure first occurs with an additional pore pressure of 20 MPa. Presumed failure planes form a conjugate set and strike NW and NE. Slip failure is more likely than tensional failure in the volcanic rocks because high normal Stresses prevent tensional failure. These results from slip tendency analysis are supported by the spatial distribution of recorded microseismicity. Source characteristics indicate slip rather than extension along presumed NE striking failure planes. This suggests that slip tendency analysis is an appropriate method that can be used to understand reservoir behavior under modified Stress conditions.
Huihu Liu - One of the best experts on this subject based on the ideXlab platform.
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characteristics of an in Situ Stress Field and its control on coal fractures and coal permeability in the gucheng block southern qinshui basin china
Journal of Natural Gas Science and Engineering, 2016Co-Authors: Huihu Liu, Shuxu Sang, Junhua Xue, Guoxiong Wang, Changjiang Liu, Shiqi LiuAbstract:The Stress characteristics in a lean coal reservoir in the Gucheng block, southern Qinshui Basin, are discussed in this study. Relational models among the Stress, burial depth and permeability in coal reservoir No. 3 in the Shanxi Formation were built, and the relationships among the coal fractures, coal permeabilities and distribution of the modern Stress were analyzed. In the Gucheng block of the southern Qinshui Basin, the distribution of modern Stress and its control on coal fractures and coal permeability have been determined using geological and statistical methods applied to subsurface observations of coal rocks, log interpretations of 50 coalbed methane wells, in Situ Stress data from 8 coalbed methane wells, monitoring data on fractures and seismic results from 14 coalbed methane wells. The results show that the coal reservoirs have ultra-low to low permeabilities (<0.1 mD). The maximum horizontal principal Stresses in the study area range from 13.23 to 29.55 MPa, with an average of 20.45 MPa; the minimum horizontal principal Stresses in the study area range from 7.7 to 19.81 MPa, with an average of 13.01 MPa; and the closure pressures vary from 9.69 to 20.76 MPa, with the average value of 13.71 MPa. Additionally, the maximum and minimum horizontal principal Stresses and the vertical principal Stress have a positive relationship with burial depth, and the permeability derived from well tests is negatively correlated with the minimum horizontal principal Stress. The maximum and minimum horizontal principal Stresses decrease from the southwest to the northeast. The in Situ modern Stress state is Situated in a transitional zone between extensional and compressional zones. The interpretation results based on the special logging and fracture monitoring results show that the modern principal Stress direction is mainly NNE to NEE and that the principal Stress direction is oriented from the north to the south. The modern principal direction is similar to the most common orientation of the coal fractures and is normal to the subordinate direction of the coal fractures. Finally, the pores and the fracture in the coal reservoir become smaller and poorer in the area with concentrated horizontal principal Stress.