The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform
Hailong Jiang - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of failure mechanism of horizontal borehole in transversely isotropic shale gas reservoirs
Journal of Natural Gas Science and Engineering, 2017Co-Authors: Lichun Jia, Mian Chen, Yan Jin, Hailong JiangAbstract:Abstract Usually, the shale gas reservoirs are characterized by well-developed weak planes, which results in complex borehole instability issues during horizontal drilling. To better understand the borehole collapse, the present work is to model the borehole failure by using the particle fLow code (PFC 2D ). Firstly, the model of shale is developed in form of layered formations. Then, effect of different factors including the Wellbore Pressure, weak planes number, formations dip angles, mechanical properties of weak planes and the stress states are discussed respectively. The simulation results reveal that the failure of weak planes is particularly prominent and the ultimate cracks mainly concentrate in weak planes. The collapse zone gradually enlarges as the Wellbore Pressure decreases, which results in square borehole in Low Wellbore Pressure. As the number of weak planes decreases, the number of fractures also decreases gradually. When the dip angle of weak planes is 30° and 60°, the number of sliding fractures is higher than that of 0° and 90° dip angle, which is opposite to the uniaxial compression strength. The fractures gradually decrease as the mechanical properties of weak planes strengthen, indicating that the weak planes become much stable gradually. The horizontal borehole drilling along the direction of maximum horizontal in-situ stress is much stable in this study. The results agree well with those observed in laboratory and in field. This numerical approach is very helpful to understand the failure mechanism of borehole in shale gas reservoirs.
Lichun Jia - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of failure mechanism of horizontal borehole in transversely isotropic shale gas reservoirs
Journal of Natural Gas Science and Engineering, 2017Co-Authors: Lichun Jia, Mian Chen, Yan Jin, Hailong JiangAbstract:Abstract Usually, the shale gas reservoirs are characterized by well-developed weak planes, which results in complex borehole instability issues during horizontal drilling. To better understand the borehole collapse, the present work is to model the borehole failure by using the particle fLow code (PFC 2D ). Firstly, the model of shale is developed in form of layered formations. Then, effect of different factors including the Wellbore Pressure, weak planes number, formations dip angles, mechanical properties of weak planes and the stress states are discussed respectively. The simulation results reveal that the failure of weak planes is particularly prominent and the ultimate cracks mainly concentrate in weak planes. The collapse zone gradually enlarges as the Wellbore Pressure decreases, which results in square borehole in Low Wellbore Pressure. As the number of weak planes decreases, the number of fractures also decreases gradually. When the dip angle of weak planes is 30° and 60°, the number of sliding fractures is higher than that of 0° and 90° dip angle, which is opposite to the uniaxial compression strength. The fractures gradually decrease as the mechanical properties of weak planes strengthen, indicating that the weak planes become much stable gradually. The horizontal borehole drilling along the direction of maximum horizontal in-situ stress is much stable in this study. The results agree well with those observed in laboratory and in field. This numerical approach is very helpful to understand the failure mechanism of borehole in shale gas reservoirs.
Mian Chen - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of failure mechanism of horizontal borehole in transversely isotropic shale gas reservoirs
Journal of Natural Gas Science and Engineering, 2017Co-Authors: Lichun Jia, Mian Chen, Yan Jin, Hailong JiangAbstract:Abstract Usually, the shale gas reservoirs are characterized by well-developed weak planes, which results in complex borehole instability issues during horizontal drilling. To better understand the borehole collapse, the present work is to model the borehole failure by using the particle fLow code (PFC 2D ). Firstly, the model of shale is developed in form of layered formations. Then, effect of different factors including the Wellbore Pressure, weak planes number, formations dip angles, mechanical properties of weak planes and the stress states are discussed respectively. The simulation results reveal that the failure of weak planes is particularly prominent and the ultimate cracks mainly concentrate in weak planes. The collapse zone gradually enlarges as the Wellbore Pressure decreases, which results in square borehole in Low Wellbore Pressure. As the number of weak planes decreases, the number of fractures also decreases gradually. When the dip angle of weak planes is 30° and 60°, the number of sliding fractures is higher than that of 0° and 90° dip angle, which is opposite to the uniaxial compression strength. The fractures gradually decrease as the mechanical properties of weak planes strengthen, indicating that the weak planes become much stable gradually. The horizontal borehole drilling along the direction of maximum horizontal in-situ stress is much stable in this study. The results agree well with those observed in laboratory and in field. This numerical approach is very helpful to understand the failure mechanism of borehole in shale gas reservoirs.
Yan Jin - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of failure mechanism of horizontal borehole in transversely isotropic shale gas reservoirs
Journal of Natural Gas Science and Engineering, 2017Co-Authors: Lichun Jia, Mian Chen, Yan Jin, Hailong JiangAbstract:Abstract Usually, the shale gas reservoirs are characterized by well-developed weak planes, which results in complex borehole instability issues during horizontal drilling. To better understand the borehole collapse, the present work is to model the borehole failure by using the particle fLow code (PFC 2D ). Firstly, the model of shale is developed in form of layered formations. Then, effect of different factors including the Wellbore Pressure, weak planes number, formations dip angles, mechanical properties of weak planes and the stress states are discussed respectively. The simulation results reveal that the failure of weak planes is particularly prominent and the ultimate cracks mainly concentrate in weak planes. The collapse zone gradually enlarges as the Wellbore Pressure decreases, which results in square borehole in Low Wellbore Pressure. As the number of weak planes decreases, the number of fractures also decreases gradually. When the dip angle of weak planes is 30° and 60°, the number of sliding fractures is higher than that of 0° and 90° dip angle, which is opposite to the uniaxial compression strength. The fractures gradually decrease as the mechanical properties of weak planes strengthen, indicating that the weak planes become much stable gradually. The horizontal borehole drilling along the direction of maximum horizontal in-situ stress is much stable in this study. The results agree well with those observed in laboratory and in field. This numerical approach is very helpful to understand the failure mechanism of borehole in shale gas reservoirs.
Zhou Xiaohong - One of the best experts on this subject based on the ideXlab platform.
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A MATHEMATICAL MODEL OF CALCULATING COLLAPSE Pressure FOR FRACTURE FORMATION
Drilling & Production Technology, 2012Co-Authors: Zhou XiaohongAbstract:Fracture formation has many characters,such as well-developed fracture,micro-fracture and bedding,obvious aeolotropism,high collapse Pressure and narrow safe mud density window,the borehole is easily to fall in with Low Wellbore Pressure,and lost circulation with high Wellbore Pressure.Distinguished with homogeneous and isotropic rock formations,the mechanics stability of these boreholes in such formations mainly depends on the unit body structural plane intensity(antiskid capacity).The wall rock would experience destabilizing when the stress acted on unit body exceeded their antiskid capacity.On the basis of the theory of the mechanics stability of wall rock in isotropic homogeneity formations,a new mathematical model based on Mohr-Coulomb Criterion was established to calculate the collapse Pressure of fracture formations,and break degree(Bd) of rock formation was introduced into the new formula to quantitatively describe the influence of the rock fragmentation degree on in-situ stress.Example showed that the calculation results of the new model were consistent with practice.
