• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Rotational failure analysis of spherical-cylindrical shell pressure controllers related to gas hydrate drilling investigations

    2022-06-02 05:00:50CongLiJinLingPiNinHnWuGuiKngLiuWiHungZhiXuDiRuiWngZhoFnChnWiChngLong
    Petroleum Science 2022年2期

    Cong Li ,Jin-Ling Pi ,Nin-Hn Wu ,Gui-Kng Liu ,Wi Hung ,Zhi-Xu Di ,Rui-Z Wng ,Zho-Fn Chn ,Wi-Chng Long

    a MOE Key Laboratory of Deep Earth Science and Engineering,Sichuan University,College of Water Resource and Hydropower,Sichuan University,Chengdu,610065,China

    b Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization,Institute of Deep Earth Sciences and Green Energy,College of Civil and Transportation Engineering,Shenzhen University,Shenzhen,518060,China

    c China Pingmei Shenma Energy and Chemical Industry Group Co.,Ltd.,Pingdingshan,467000,China

    d State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization,Pingdingshan,467000,China

    e Xi'an Research Institute,China Coal Technology and Engineering Group,Xi'an,710077,China

    Keywords:Exploration of oil and gas resources Pressure coring controller Sphere flapper valve Failure modes Stress deviation rate

    ABSTRACT In situ pressure-preserved coring (IPP-Coring) technology is considered one of the most efficient methods for assessing resources.However,seal failure caused by the rotation of pressure controllers greatly affects the success of pressure coring.In this paper,a novel spherical-cylindrical shell pressure controller was proposed.The finite element analysis model was used to analyze the stress distribution and deformation characteristics of the pressure controller at different rotation angles.The seal failure mechanism caused by the rotation of the pressure controller was discussed.The stress deviation rate was defined to quantitatively characterize the stress concentration.Based on the test equipment designed in this laboratory,the ultimate bearing strength of the pressure controller was tested.The results show that the rotation of the valve cover causes an increase in the deformation on its lower side.Furthermore,the specific sealing pressure in the weak zone is greatly reduced by a statistically significant amount,resulting in seal failure.When the valve cover rotates 5° around the major axis,the stress deviation rate is -92.6%.To prevent rotating failure of the pressure controller,it is necessary to control the rotation angle of the valve cover within 1° around the major axis.The results of this research can help engineers reduce failure-related accidents,provide countermeasures for pressure coring,and contribute to the exploration and evaluation of deep oil and gas resources.

    1.Introduction

    Natural gas hydrate is widely considered the most promising clean energy source for the future (Sloan,2003;Pang et al.,2021).Countries worldwide are actively exploring the technology of natural gas-hydrates,which has greatly promoted the development of natural gas hydrates(Hu et al.,2021;Saberi et al.,2021;Gao et al.,2022).The potential impact of NGH development on the global carbon cycle (Dickens et al.,1997),sustainable environmental change (Archer,2007),drilling hazards and future energy production (Boswell and Collett,2011) are issues to be explored at the frontier of science (Singh et al.,1993).Scientific research mainly focuses on the following aspects:

    ●the development of exploration technology and equipment,including physical exploration technology and pressure coring technology,and the establishment of a scientific evaluation system(Jin et al.,2014;Gao et al.,2021;He et al.,2021;Huang et al.,2021;Kida et al.,2021),

    ●the study of the physical and mechanical properties of in-situ NGH and the development of economic and efficient mining methods (Konno et al.,2013;Jing et al.,2015;Aydin and Merey,2021;Fu et al.,2021;Gao et al.,2021;Gao et al.2021,2021;Ruan et al.,2021),and

    ●the assessment of natural hazards brought about by largescale mining and the formulation of corresponding preventive measures (Borowski et al.,1996;Chen and Guo,1998;Collett,2002;Wang and Sun,2009;Gao et al.2018,2020;Veluswamy and Linga,2021).

    However,the formation mechanism of NGH reservoirs is very complex (Zhang et al.,2011;Shagapov and Tazetdinov 2014).During sampling,core recovery or subsequent testing,if the temperature and pressure environment of NGH changes,then the physical properties,internal structure and mechanical properties of hydrate-bearing sediments may change to a statistically significant extent (Gao et al.2020,2021;He et al.,2021).It is difficult to retrieve in situ NGH.To solve this problem,in-situ pressurepreserved coring (IPP-Coring) has been developed as an effective method to extract hydrate deposits from underground sediments and preserve the samples under in situ hydrostatic pressure (Dai and Santamarina,2014).

    There are various pressure coring systems,but all of these systems aim to transfer unchanged cores to the surface(Li et al.,2016).In the 1970s,the early Pressure Core Barrel (PCB) was adopted by the Deep Sea Drilling Project (DSDP).The success rate of core recovery was very low due to the ball valve closing problem.In 1983,the international Ocean Drilling Program (ODP) developed the Pressure Core Sampler(PCS)and obtained samples of NGH without affecting their pressure from the Blake Outer Ridge.The sediment was recovered by a rotary or push rod coring machine and sealed by a ball valve.The operating pressure was 70 MPa.The first systematic pressure core sampling occurred during ODP 164 drilling in 1995.The Hydrate Autoclave Coring Equipment System (HYACE),funded by the European Union's Marine Science and Technology Program,was developed in the late 1990s.Two types of wireline pressure corers were developed within the HYACE:the Fugro Pressure Core (FPC) and the HYACE Rotary Corer (HRC) samplers.The more recent HYACINTH (Deployment of HYACE tools In New Tests on Hydrates) project is designed to transfer the collected cores from the coring device to the measuring chamber without pressure leakage.The HYACINTH system includes not only coring tools,such as the FPC,HRC,the Fugro Rotary Pressure Core(FRPC)and the Submarine Gas Hydraulic Reserves (SUGAR) corer (SUCO)but so a series of subsequent core testing and processing equipment.The MAC (Multiple Autoclave Corer) and DAPC (Dynamic Autoclave Piston Corer) were developed and used in Germany in 2002 and 2003,respectively.In 2005,the Joint Industry Project(JIP)used HYACE FPC and HRC to obtain pressure cores,and the Instrumented Pressure Testing Chamber (IPTC) instrument developed by USGS and Georgia Institute of Technology to analyze cores under in situ pressure environments.PCB,PCS,HRC and FPC could not maintain the in situ temperature.Therefore,Japan Oil,Gas and Metals National Corporation(JOGMEC)invented the PTCS(Pressure Temperature Core Sampler) for the first time,which can work under a pressure of 30 MPa and has been used in the Nankai Trough.The PTCS is effective in sandstone sediments.Since 2000,the Hybrid-Pressure Core Sampler (Hybrid-PCS) or Pressure Core Tool with Ballvalve(PCTB)has been used in offshore drilling projects in China(Zhang et al.,2019),the UK and other countries.The HYACE/Fugro FPC and FRPC systems are also used offshore Korea and in the Gulf of Mexico.In China,Zhejiang University developed a gravity piston-type coring device.Zhu et al.developed an NGH coring device with the Pressure and Temperature Preservation System(PTPS).A brief overview of the IPP-Coring is shown in Fig.1.

    In conclusion,core is the first complete data in the process of petroleum exploration and development.The pressure controller of the coring device is the key to the success of the IPP-Coring (Xie et al.,2021).Ball valve or flap valve is commonly used as the sealing structure in existing pressure coring devices.Among the hydrate-bearing sediment samples retrieved by pressure coring devices,more than 30%of the samples do not retain the pressure or only retain part of the in situ pressure,resulting in high deployments cost.This study proposes a new shell pressure controller with a novel spheric-cylindric structure intended to have a higher ultimate bearing strength and investigates its rotation failure.Further,the recovery rate of pressure maintaining coring is improved through failure mechanism analysis.

    2.Design of spherical-cylindrical shell pressure controllers

    Fig.1.A brief overview of pressure coring technologies.

    The pressure controller is a sealing mechanism(generally a ball valve or flap valve)and determines the ultimate pressure strength of the pressure coring device(Gao et al.,2021).This paper presents a new principle of pressure coring for maintaining the coring pressure.The valve cover of the pressure controller is initially erected in the corer (shown in Fig.2).When the coring is completed,the inner cylinder is released.Then,the valve cover turns over to the matching valve seat.Flapper valve sealing mechanisms can maximize the core diameter and downhole drive mechanisms to ensure core quality.Based on the principle of intersecting spherical shells and cylindrical shells,this new configuration,referred to as a spherical-cylindrical shell pressure controller (Fig.2),is proposed.The spherical-cylindrical shell pressure controller consists of a cylindrical valve cover with a spherical edge and a matching seat.The traditional conical contact has a horizontal thrust,which greatly affects the pressurepreserved capacity of the IPP-Coring.The new structure adjusts the contact form between the valve cover and the valve seat so that there is only a normal support force.Compared with the conventional conical pressure controller,the spherical-cylindrical shell pressure controller has smaller structural deformation and higher bearing strength (Li et al.,2021).However,the contact pattern of the spherical-cylindrical shell pressure controller is similar to that of the spherical hinge.Thus,the two parts easily rotate around the common spherical center (Fig.3).The maintenance of oil and gas pressure puts forward strict requirements for the performance of the structure (Li et al.,2021).The rotation failure of the pressure controller needs to be further studied.

    Fig.2.Spherical-cylindrical shell pressure controller.

    3.Influence of rotation angle on spherical-cylindrical shell pressure controllers

    3.1.Simulation procedures

    ABAQUS is a powerful engineering numerical simulation software based on finite element method,which can solve linear and nonlinear problems in a wide range of fields.In the paper,to analyze the failure mechanism of the structure,numerical simulation is carried out based on ABAQUS software.The elastoplastic model is adopted,which is based on the fundament assumptions of isotropic elasticity continuum,i.e.,elasticity,homogeneity,isotropy and small deformation(see Fig.4).

    Based on the ABAQUS/CAE User's Manual and elasto-plasticity theory (Lubarda,2002),the general constitutive equation for an elastic-plastic material is briefly introduced.The stress increment,{dσ} can be expressed in terms of the elastic strain increment,{dεe},as

    Fig.3.Rotation of spherical-cylindrical shell pressure controllers.

    Fig.4.Establishment of a solid mechanics problem.

    Fig.5.The mesh of a spherical-cylindrical shell pressure controller.

    and

    with

    Fig.6.Boundary conditions.

    where[C]is the tensor of elastic modulus in matrix form,{dε}is the total strain increment,{dεp}is the plastic strain increment,dλ is the scalar function,{?g/?{σ}} is the gradient vector of the plastic potential function,L is the loading criterion function,h is the positive scalar function.The stress calculation will be performed for all Gaussian sampling points.

    3.2.Model setup

    To study the stress distribution and failure mechanism,a geometric model(shown in Fig.5)is established.The sealing groove is simplified.Hexahedral mesh is used.The boundary condition is shown in Fig.6.The underside of the seat is fully restrained.A simulated in situ hydrostatic pressure is applied to the top surface of the valve cover.Alloy 304 stainless steel is used as the test material.The original gauge length of the specimen is 32 mm.The tensile test(shown in Fig.7)is carried out on a Shimadzu electronic testing machine.The yield strength and tensile strength are 613.6 MPa and 828.6 MPa,respectively.The friction coefficient of the contact surface is 0.2.

    Fig.7.Tensile test results of stainless steel.

    Fig.8.Equivalent stress distribution of valve cover with different rotation angles.

    3.3.Simulation results

    The stress distribution of the valve cover is shown in Fig.8 with different rotation angles.There are two low stress zones,A and B,in the middle bottom surface of the valve cover.With the increase in the z-axis rotation angle,the left equivalent stress gradually decreases,and the left low stress area C expands.With the increase in the rotation angle around the x-axis and z-axis,the equivalent stresses in A and D increase continuously.The equivalent stress in zone C decreases continuously.This means that zone C may not be able to provide effective sealing pressure,which is the potential weak site of leakage.

    Three measuring lines are defined(as shown in Fig.9(a))where L1 and L2 are the monitoring lines along the minor axis and major axis,respectively,and L3 is the circumferential monitoring line of the valve cover.Fig.9(b)shows that with increasing z-axis rotation angle,the stress on L1 shows a decreasing trend.The stress deviation rate is defined as

    where ω is the stress deviation rate,and σNand σRare the stress values without rotation and after a certain angle of rotation,respectively.

    The stress deviation rates of L1 are -11.2,-75.4,and -92.6%when rotating 1,3,and 5°around the z-axis and rotating 0°around the x-axis.Fig.9 (c) and Fig.9 (d) show the stress distributions of the L1 and L2 measuring lines with different x-axis rotation angles.With the increase in the x-axis rotation angle,the stress deviation increases gradually.Compared with the x-axis rotation,the rotation around the z-axis has a more obvious effect on the stress deviation of L1.In fact,spherical-cylindrical shell pressure controllers may simultaneously experience the influences of x-axis and z-axis rotations.Fig.10 shows the stress distribution of L1 under the xz compound rotation.When rotating 5°around the x-axis,the stress deviation rates for 0,1,3 and 5°around the z-axis are-10.7,-58.9,-72.2 and-92.4%,respectively.The larger the xaxis rotation angle is,the greater the stress drop.

    According to the numerical simulation results,the valve cover can form a strong support along the major axis.The low stress zone C is likely to be the weak site of leakage.The deformation along the minor axis is the main factor affecting the structural strength of the valve cover.The effect of z-axis rotation on the monitoring line L3 is much higher than that of the x-axis(see Fig.11).For instance,when rotating 5°around the z-axis and 0°around the x-axis,the stress deviation rate reaches 92.6%.It is difficult to provide enough contact pressure for the sealing surface.Finally,the overall strength of the pressure controller is invalid.In the engineering practice of pressure coring,the sealing performance is very important for maintaining oil and gas pressure.Due to the stress redistribution during the rotation of the structure,the stress at the edge of the valve cover is reduced,and the fluid medium with pressure will leak from the contact surfaces.

    Fig.9.Equivalent stress distribution of different measuring lines.

    4.Failure pressure of spherical shell pressure controller

    The deformation characteristics and sealing stability of the pressure controller are very important to the success rate of pressure coring.However,there is no special test device for evaluating pressure controllers domestically and abroad.Therefore,we developed a pressure controller test platform that,according to the size of the coring device,can test the failure pressure of pressure controllers with different configurations.

    4.1.Testing system

    To obtain the failure pressure of the spherical-cylindrical shell pressure controllers under different working conditions,an experimental platform(Fig.12)was designed in this laboratory.The specimen was installed inside the test chamber.Then,water was pumped to the chamber through the injection port until the specimen failed.The watertight joint provided a data channel for the strain gauge at the top of the valve cover.According to the numerical simulations,the positions of three strain gauges were determined.Among them,SG-1,SG-2 and SG-3 were the equivalent stress concentration area,the large deformation area and the stress concentration edge,respectively.

    4.2.Physical experiment results

    Two tests were carried out based on the test system.The pressure controllers before and after the test are shown in Fig.13(a).Under the condition of high pressure,the sealing ring was damaged due to the insufficient contact pressure in the weak area C.

    Fig.14(a)shows that with the increasing load,the strains of SG-1Z and SG-2Z were gradually increasing tensile deformation,while the strains of SG-1X,SG-2X and SG-3X were compressive deformation.After a certain rotation angle,the ultimate bearing strength was only 8.4 MPa.After the failure of the pressure controller,the pressure in the test chamber decreases,and the strain data tended to zero.The compressive strains in SG-1X and SG-2X were the largest,4.02 × 10-4and 4.43 × 10-4,respectively.Torsional instability occurred in the pressure controller,and the force on the valve cover was uneven.There was a notch on one side of the seat(Fig.15).According to the second test results under the same conditions,the maximum bearing strength of the spherical pressure controller was 43.8 MPa (shown in Fig.14(b)).There was a great gap due to the rotation of the structure.Therefore,it was necessary to add a limiting surface to reduce the rotation of the structure.

    According to the numerical simulations and laboratory tests,the bearing strengths are greatly reduced by rotation to any angle.The strains predicted by the numerical simulations are basically consistent with the experimental results.As seen from Fig.16,the strain on the left side of the cover is very small,which means that the contact pressure at this position is small.The sealing ring is extruded from the enlarged gap,which is consistent with the physical experimental results.Therefore,by adjusting the angle of the valve cover,the structural strength is increased from 8.4 to 43.8 MPa.

    Fig.10.Stress distribution of L1 under XZ compound rotation.

    Fig.11.Equivalent stress distributions of L3 under different rotation angles.

    The in situ physical and mechanical properties are crucial for deep oil and gas exploration.The paper focuses on the pressure controllers,which is one of the key components of deep-sea pressure coring device.It can obtain cores with deep-sea in situ pressure.On the one hand,pressure cores are the premise of quantitative evaluation of in situ permeability and saturation of oil and gas.It is of great significance for understanding geological conditions,evaluating recoverable reserves and improving recovery rate.On the other hand,it provides a technical means for the study of in situ mechanical parameters of natural gas hydrate,affecting the efficiency of industrial production.Through the research of this paper,the strength of the developed IPP-Coring can be suitable for in situ applications at depths of thousands of meters,and cores with higher pressures can be obtained.This capability of the newly developed pressure coring device not only effectively ensures the safety and lives of on-site operators,but also brings certain economic benefits.

    Fig.12.Test equipment designed in this laboratory.

    Fig.13.Spherical pressure controller.

    Fig.14.Physical test results.

    5.Conclusion

    The conclusions are as follows:

    1.Based on the principle of intersecting spherical shells and cylindrical shells,a new structure for a spherical-cylindrical shell pressure retaining controller is designed.Through numerical simulation and experimental test,its ultimate bearing strength reaches 43.8 MPa.

    Fig.15.Unbalanced notch in the valve seat caused by structural rotation.

    Fig.16.Strain of the pressure controller.

    2.The rotation of the valve cover increases the deformation of the valve cover,which greatly reduces the contact pressure of the sealing surface,resulting in sealing failure.To quantitatively characterize the stress concentration caused by the rotation,the stress deviation rate is defined.The effect of z-axis rotation is much greater than that of x-axis rotation.When rotating 5°around the z-axis,the equivalent stress drop is -92.6%.

    3.The contact pressure reduction caused by rotation is the root cause of the failure of the pressure maintaining controller.To prevent the rotational failure,an anti-rotation structure should be adopted to control the valve cover rotation within 1°around the major axis.

    IPP-Coring has a great influence on the measurement of oil and gas saturation parameters.The fluid saturation provided by analysis of core obtained by pressure coring can better represent the original reservoir state than that provided by conventional core analysis,especially in cases of the evaluation of gas reservoir reserves and the feasibility of enhanced oil recovery.This study reveals the rotation failure principle of spherical pressure controllers,which can help to improve the success rate of pressure coring and provide technical support for the exploration and evaluation of deep oil and gas resources.

    Declaration of competing interest

    The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

    Acknowledgments

    The paper was supported by the Program for Guangdong Introducing Innovative and Enterpreneurial Teams (No.2019ZT08G315) and National Natural Science Foundation of China No.51827901 and U2013603.

    亚洲美女视频黄频| 欧美精品国产亚洲| 一级毛片我不卡| 成人二区视频| 伊人久久精品亚洲午夜| 久久精品人妻少妇| 亚洲18禁久久av| 成年女人在线观看亚洲视频 | 国产伦一二天堂av在线观看| 日本与韩国留学比较| 亚洲内射少妇av| 成人午夜高清在线视频| 亚洲成人一二三区av| 久久久欧美国产精品| 人妻制服诱惑在线中文字幕| 97人妻精品一区二区三区麻豆| 国产亚洲午夜精品一区二区久久 | 高清在线视频一区二区三区| 精品不卡国产一区二区三区| 最近最新中文字幕免费大全7| 国产av国产精品国产| 色视频www国产| 赤兔流量卡办理| 纵有疾风起免费观看全集完整版 | 午夜激情福利司机影院| 国产成人午夜福利电影在线观看| 国产黄频视频在线观看| 久久99热这里只频精品6学生| 日韩一区二区三区影片| 久久久久久久久中文| 一区二区三区高清视频在线| 久久精品综合一区二区三区| 建设人人有责人人尽责人人享有的 | 欧美日韩在线观看h| 我要看日韩黄色一级片| 女人被狂操c到高潮| 亚洲精品一二三| 成人毛片a级毛片在线播放| 亚洲av.av天堂| 91精品伊人久久大香线蕉| 中文字幕亚洲精品专区| av福利片在线观看| 亚洲伊人久久精品综合| 一区二区三区乱码不卡18| 直男gayav资源| 成人亚洲精品一区在线观看 | 波野结衣二区三区在线| 久久久久久久久大av| 六月丁香七月| 亚洲av成人精品一区久久| 一级毛片黄色毛片免费观看视频| 一级片'在线观看视频| 久久久色成人| 欧美97在线视频| 寂寞人妻少妇视频99o| 日韩欧美三级三区| 狂野欧美白嫩少妇大欣赏| av专区在线播放| 22中文网久久字幕| 18禁在线播放成人免费| 午夜福利成人在线免费观看| 熟女电影av网| 一边亲一边摸免费视频| 亚洲成人久久爱视频| 成人午夜精彩视频在线观看| 婷婷色麻豆天堂久久| 国产亚洲最大av| 久久人人爽人人片av| 国产成人午夜福利电影在线观看| 免费看a级黄色片| 青春草亚洲视频在线观看| 亚洲精品成人av观看孕妇| 国产精品不卡视频一区二区| 黄片wwwwww| 亚洲国产精品成人综合色| 久久久久久久大尺度免费视频| 日韩国内少妇激情av| 日韩中字成人| 少妇猛男粗大的猛烈进出视频 | 插逼视频在线观看| 九色成人免费人妻av| 亚洲欧美一区二区三区国产| 亚洲最大成人中文| 免费不卡的大黄色大毛片视频在线观看 | 亚洲在久久综合| 少妇人妻一区二区三区视频| 亚洲婷婷狠狠爱综合网| 免费观看精品视频网站| 男人舔奶头视频| 欧美一区二区亚洲| 国产单亲对白刺激| 国产av码专区亚洲av| 国产一区亚洲一区在线观看| 日韩亚洲欧美综合| 人妻一区二区av| 国产真实伦视频高清在线观看| 国精品久久久久久国模美| 熟妇人妻不卡中文字幕| 人妻夜夜爽99麻豆av| 一级毛片电影观看| 中文字幕免费在线视频6| 亚洲色图av天堂| 免费av毛片视频| 日本欧美国产在线视频| kizo精华| 少妇丰满av| 亚洲婷婷狠狠爱综合网| 国产免费又黄又爽又色| 日韩欧美精品v在线| 91在线精品国自产拍蜜月| 久久精品国产亚洲av天美| 最近中文字幕2019免费版| 亚洲av免费在线观看| 久久久久网色| 欧美人与善性xxx| 少妇丰满av| 一本久久精品| 97超碰精品成人国产| 国产午夜精品久久久久久一区二区三区| 国产av国产精品国产| 亚洲精品一区蜜桃| 亚洲欧美一区二区三区黑人 | .国产精品久久| 免费av毛片视频| 男人爽女人下面视频在线观看| 日韩一区二区视频免费看| 日日啪夜夜撸| 丰满少妇做爰视频| 天堂av国产一区二区熟女人妻| 亚洲乱码一区二区免费版| 国产免费视频播放在线视频 | 听说在线观看完整版免费高清| 色视频www国产| 久久久久久久久久久免费av| 亚洲欧洲日产国产| 中文字幕亚洲精品专区| 国产精品久久久久久久电影| 偷拍熟女少妇极品色| 九九爱精品视频在线观看| 日本免费在线观看一区| 青春草亚洲视频在线观看| 午夜精品国产一区二区电影 | 国产av不卡久久| 亚洲国产精品成人久久小说| 看免费成人av毛片| 亚洲熟妇中文字幕五十中出| 久久草成人影院| 成人亚洲精品一区在线观看 | ponron亚洲| 免费看美女性在线毛片视频| 日本一本二区三区精品| 亚洲精品成人久久久久久| 能在线免费看毛片的网站| 亚洲天堂国产精品一区在线| 日韩av不卡免费在线播放| 久久99热这里只频精品6学生| 极品少妇高潮喷水抽搐| 亚洲av国产av综合av卡| 欧美xxxx黑人xx丫x性爽| 成人一区二区视频在线观看| 少妇被粗大猛烈的视频| 最近的中文字幕免费完整| 亚洲在久久综合| 色吧在线观看| 久久精品久久久久久久性| 波野结衣二区三区在线| 床上黄色一级片| 欧美xxxx性猛交bbbb| 内射极品少妇av片p| 日韩制服骚丝袜av| 国产精品一二三区在线看| 亚洲色图av天堂| 亚洲内射少妇av| 一级av片app| 欧美区成人在线视频| 97在线视频观看| 中文字幕亚洲精品专区| 国内少妇人妻偷人精品xxx网站| 综合色丁香网| 午夜免费观看性视频| 免费观看a级毛片全部| 六月丁香七月| 高清视频免费观看一区二区 | 赤兔流量卡办理| 久久久久精品久久久久真实原创| 少妇熟女欧美另类| 九九在线视频观看精品| 国产综合精华液| 乱码一卡2卡4卡精品| 91午夜精品亚洲一区二区三区| 午夜亚洲福利在线播放| 免费少妇av软件| 亚洲国产精品sss在线观看| 18禁裸乳无遮挡免费网站照片| 午夜免费观看性视频| 久久久久精品久久久久真实原创| 国产乱来视频区| 久久久久久久久久人人人人人人| 校园人妻丝袜中文字幕| 久久精品熟女亚洲av麻豆精品 | 午夜爱爱视频在线播放| 亚洲成人av在线免费| 国产精品日韩av在线免费观看| 中文字幕亚洲精品专区| 久久99精品国语久久久| 一本久久精品| 久久久久久久久久成人| 国产精品日韩av在线免费观看| 九九爱精品视频在线观看| 22中文网久久字幕| 高清欧美精品videossex| 高清视频免费观看一区二区 | 在线天堂最新版资源| 嫩草影院精品99| 极品少妇高潮喷水抽搐| 看非洲黑人一级黄片| 成年人午夜在线观看视频 | 国产精品爽爽va在线观看网站| 久久精品国产亚洲av天美| 亚洲av中文av极速乱| 一级毛片我不卡| 亚洲精品一二三| 日韩欧美三级三区| 国产久久久一区二区三区| 神马国产精品三级电影在线观看| 婷婷色综合www| 不卡视频在线观看欧美| 91久久精品国产一区二区三区| 精品久久久久久久久久久久久| 免费高清在线观看视频在线观看| 久久久久网色| 亚洲国产高清在线一区二区三| 日韩成人av中文字幕在线观看| 亚洲天堂国产精品一区在线| 我的老师免费观看完整版| 国产精品三级大全| 久久精品国产鲁丝片午夜精品| 久久久久久九九精品二区国产| 少妇猛男粗大的猛烈进出视频 | 国产三级在线视频| 亚洲国产色片| 你懂的网址亚洲精品在线观看| 国产精品女同一区二区软件| 日韩一区二区视频免费看| 精品久久久久久电影网| 一级av片app| 91久久精品电影网| 一本久久精品| 99久久九九国产精品国产免费| 麻豆国产97在线/欧美| 亚洲久久久久久中文字幕| 亚洲精品乱码久久久久久按摩| 18禁在线无遮挡免费观看视频| 国产精品人妻久久久久久| 97超视频在线观看视频| 亚洲精品456在线播放app| 成人毛片60女人毛片免费| 欧美zozozo另类| 国产午夜精品一二区理论片| 亚洲av福利一区| 亚洲久久久久久中文字幕| 只有这里有精品99| 一本久久精品| 国产高清不卡午夜福利| 69av精品久久久久久| 亚洲精品一二三| 精品午夜福利在线看| 中文字幕免费在线视频6| 汤姆久久久久久久影院中文字幕 | 少妇高潮的动态图| 观看美女的网站| 国产探花在线观看一区二区| 免费不卡的大黄色大毛片视频在线观看 | 久久热精品热| av女优亚洲男人天堂| 国产白丝娇喘喷水9色精品| 成人漫画全彩无遮挡| 成人综合一区亚洲| 亚州av有码| 亚洲久久久久久中文字幕| 久久99蜜桃精品久久| 男人爽女人下面视频在线观看| 成人亚洲欧美一区二区av| 超碰av人人做人人爽久久| 可以在线观看毛片的网站| 色吧在线观看| videos熟女内射| 3wmmmm亚洲av在线观看| 国产精品蜜桃在线观看| 中文欧美无线码| 少妇人妻精品综合一区二区| 国产高潮美女av| 欧美成人一区二区免费高清观看| 国产精品1区2区在线观看.| 欧美日韩视频高清一区二区三区二| 午夜视频国产福利| 床上黄色一级片| 丝袜喷水一区| 我的女老师完整版在线观看| 80岁老熟妇乱子伦牲交| 少妇的逼好多水| 久久久a久久爽久久v久久| 亚洲美女视频黄频| 久久精品国产亚洲av天美| 日本色播在线视频| 国产v大片淫在线免费观看| av在线观看视频网站免费| 国产片特级美女逼逼视频| 国产男女超爽视频在线观看| 性插视频无遮挡在线免费观看| 不卡视频在线观看欧美| 91在线精品国自产拍蜜月| 中文资源天堂在线| 国产精品精品国产色婷婷| 80岁老熟妇乱子伦牲交| 国产成年人精品一区二区| 天堂影院成人在线观看| 日韩制服骚丝袜av| 精品亚洲乱码少妇综合久久| 少妇被粗大猛烈的视频| 国产精品久久久久久久久免| eeuss影院久久| 国产单亲对白刺激| 精品人妻视频免费看| 久久99热6这里只有精品| 亚洲精品亚洲一区二区| 99热全是精品| 国产黄频视频在线观看| 超碰97精品在线观看| 2022亚洲国产成人精品| 麻豆精品久久久久久蜜桃| 久久热精品热| 秋霞在线观看毛片| 2021天堂中文幕一二区在线观| 欧美xxxx性猛交bbbb| 欧美精品一区二区大全| 国产老妇伦熟女老妇高清| 成年女人看的毛片在线观看| 国产亚洲精品久久久com| 三级男女做爰猛烈吃奶摸视频| 午夜福利视频精品| 国产白丝娇喘喷水9色精品| 久久97久久精品| 99re6热这里在线精品视频| 乱人视频在线观看| 尾随美女入室| 国产黄色小视频在线观看| 在线播放无遮挡| 淫秽高清视频在线观看| 国产伦理片在线播放av一区| 日韩成人av中文字幕在线观看| 色5月婷婷丁香| 欧美性猛交╳xxx乱大交人| 80岁老熟妇乱子伦牲交| 亚洲最大成人av| 成人午夜精彩视频在线观看| 久久久精品欧美日韩精品| 久久久久久久久中文| 激情五月婷婷亚洲| 人人妻人人看人人澡| 亚洲精品国产成人久久av| 亚洲人成网站在线观看播放| 18禁在线播放成人免费| 日本熟妇午夜| 69人妻影院| 国产成人freesex在线| 搡老妇女老女人老熟妇| 国产成人freesex在线| 最近中文字幕高清免费大全6| 十八禁网站网址无遮挡 | 国产熟女欧美一区二区| 一本一本综合久久| 国产高潮美女av| 熟女人妻精品中文字幕| 汤姆久久久久久久影院中文字幕 | 国产精品一区二区性色av| 在现免费观看毛片| 亚洲精品aⅴ在线观看| 亚洲国产色片| 日日啪夜夜撸| 久久草成人影院| 黄片wwwwww| 成年av动漫网址| 精品国产三级普通话版| 亚洲av在线观看美女高潮| www.色视频.com| 成年av动漫网址| 精品久久久久久电影网| 亚洲人成网站高清观看| 男女边吃奶边做爰视频| 国产精品不卡视频一区二区| 日日干狠狠操夜夜爽| www.av在线官网国产| 亚洲欧美日韩卡通动漫| 三级男女做爰猛烈吃奶摸视频| 午夜老司机福利剧场| 欧美区成人在线视频| 午夜福利视频1000在线观看| 国产女主播在线喷水免费视频网站 | h日本视频在线播放| 国产精品久久视频播放| 国产免费福利视频在线观看| 亚洲精品日本国产第一区| 国产女主播在线喷水免费视频网站 | 国产男女超爽视频在线观看| 2021少妇久久久久久久久久久| 国产免费一级a男人的天堂| 国产人妻一区二区三区在| 国内少妇人妻偷人精品xxx网站| 最近的中文字幕免费完整| 亚洲真实伦在线观看| 亚洲成人一二三区av| 国产一区二区在线观看日韩| 乱码一卡2卡4卡精品| 国产精品一区二区三区四区久久| 亚洲av中文字字幕乱码综合| 青春草亚洲视频在线观看| 搞女人的毛片| 欧美zozozo另类| 成人亚洲欧美一区二区av| 国产亚洲av嫩草精品影院| 91久久精品电影网| 色视频www国产| 黄片wwwwww| 日日啪夜夜爽| 777米奇影视久久| 成人午夜精彩视频在线观看| 日本免费a在线| 中文字幕av在线有码专区| 免费看美女性在线毛片视频| 国产黄片美女视频| 国产亚洲精品久久久com| 男的添女的下面高潮视频| 三级国产精品片| 欧美日韩精品成人综合77777| 熟妇人妻不卡中文字幕| 亚洲精品色激情综合| 国产伦精品一区二区三区四那| 亚洲av电影在线观看一区二区三区 | 美女脱内裤让男人舔精品视频| 2021少妇久久久久久久久久久| 国产爱豆传媒在线观看| 欧美3d第一页| 亚洲国产av新网站| 精品国内亚洲2022精品成人| 激情 狠狠 欧美| 伊人久久精品亚洲午夜| 国语对白做爰xxxⅹ性视频网站| 亚洲欧美精品自产自拍| 三级毛片av免费| 日本色播在线视频| 国产亚洲av片在线观看秒播厂 | 久久久a久久爽久久v久久| 色哟哟·www| 高清视频免费观看一区二区 | 国产永久视频网站| 美女高潮的动态| 国产精品av视频在线免费观看| 国产一区有黄有色的免费视频 | 国产日韩欧美在线精品| 久久久精品欧美日韩精品| 久久久久国产网址| 春色校园在线视频观看| 精品一区在线观看国产| 麻豆乱淫一区二区| 国产白丝娇喘喷水9色精品| 国产成人精品婷婷| 午夜免费观看性视频| 国产综合精华液| .国产精品久久| 国产片特级美女逼逼视频| 国产亚洲5aaaaa淫片| 99热这里只有精品一区| 亚洲av男天堂| 久久久欧美国产精品| 久久6这里有精品| av.在线天堂| 亚洲精品第二区| 看非洲黑人一级黄片| 男女那种视频在线观看| 91久久精品国产一区二区三区| 看免费成人av毛片| 午夜爱爱视频在线播放| 五月伊人婷婷丁香| 免费少妇av软件| 中国国产av一级| 亚洲成色77777| 老司机影院成人| 2021天堂中文幕一二区在线观| 久久精品国产亚洲av天美| 2018国产大陆天天弄谢| 国产午夜精品论理片| 欧美成人a在线观看| 你懂的网址亚洲精品在线观看| 国产老妇伦熟女老妇高清| av在线观看视频网站免费| 国产久久久一区二区三区| 2018国产大陆天天弄谢| 久久鲁丝午夜福利片| 大香蕉97超碰在线| 91aial.com中文字幕在线观看| 亚洲av在线观看美女高潮| 日本猛色少妇xxxxx猛交久久| 日韩国内少妇激情av| 日本一二三区视频观看| 国产精品福利在线免费观看| 极品少妇高潮喷水抽搐| 搡老乐熟女国产| .国产精品久久| 亚洲欧美一区二区三区国产| 精品国产三级普通话版| 天堂av国产一区二区熟女人妻| 成人午夜高清在线视频| 寂寞人妻少妇视频99o| 欧美3d第一页| 亚洲精品色激情综合| 麻豆成人av视频| 亚洲va在线va天堂va国产| 婷婷色麻豆天堂久久| 99久久人妻综合| 久久久久久国产a免费观看| 亚洲最大成人中文| 在线 av 中文字幕| 亚洲成人中文字幕在线播放| 黄色欧美视频在线观看| 一个人免费在线观看电影| 成年女人看的毛片在线观看| 成人二区视频| 国产亚洲91精品色在线| 岛国毛片在线播放| 人妻少妇偷人精品九色| 热99在线观看视频| 精品久久久久久久人妻蜜臀av| 欧美激情在线99| 中文天堂在线官网| 内地一区二区视频在线| 国产精品三级大全| 亚洲成色77777| 在线免费观看不下载黄p国产| 日韩伦理黄色片| 免费人成在线观看视频色| 久久精品久久精品一区二区三区| 两个人的视频大全免费| 狠狠精品人妻久久久久久综合| 国产成人福利小说| 免费无遮挡裸体视频| 51国产日韩欧美| 精品国产三级普通话版| 久久久久久久久中文| 欧美日韩国产mv在线观看视频 | 国产高清不卡午夜福利| 青春草国产在线视频| 高清日韩中文字幕在线| 国产伦在线观看视频一区| 亚洲欧美清纯卡通| av播播在线观看一区| 老师上课跳d突然被开到最大视频| 我要看日韩黄色一级片| 精品熟女少妇av免费看| 亚洲成人一二三区av| 欧美精品国产亚洲| 成年版毛片免费区| 久久人人爽人人片av| 99热网站在线观看| 国产伦在线观看视频一区| 男人和女人高潮做爰伦理| 国产不卡一卡二| 亚洲人成网站在线观看播放| 插阴视频在线观看视频| 黄片无遮挡物在线观看| 精品一区二区三卡| 男女视频在线观看网站免费| 91午夜精品亚洲一区二区三区| 又爽又黄a免费视频| 免费看美女性在线毛片视频| 麻豆久久精品国产亚洲av| 熟妇人妻不卡中文字幕| 舔av片在线| 寂寞人妻少妇视频99o| 亚洲精品国产av蜜桃| 淫秽高清视频在线观看| 你懂的网址亚洲精品在线观看| 极品教师在线视频| 色哟哟·www| 精品不卡国产一区二区三区| 婷婷色av中文字幕| 天堂√8在线中文| 国产精品一区二区在线观看99 | 午夜福利高清视频| 日日啪夜夜爽| 校园人妻丝袜中文字幕| 精品人妻偷拍中文字幕| 老师上课跳d突然被开到最大视频| 天美传媒精品一区二区| 国产乱人视频| 国产大屁股一区二区在线视频| 亚洲精品久久午夜乱码| 男女啪啪激烈高潮av片| 丝袜喷水一区| 丝袜美腿在线中文| 国产亚洲5aaaaa淫片| 中文字幕久久专区| 久久午夜福利片| 日本与韩国留学比较| 成人一区二区视频在线观看| 97热精品久久久久久| 国产午夜精品久久久久久一区二区三区| 一级爰片在线观看| 欧美激情在线99| 亚洲真实伦在线观看| 啦啦啦韩国在线观看视频| 成人无遮挡网站| av播播在线观看一区| 午夜免费观看性视频| 午夜福利视频1000在线观看|