Wel ens综合征是一种与冠状动脉左前降支严重狭窄有关的心电图T波异常改变,其特征为心绞痛发作时心电图正常,而缓解后发生T波改变,即胸闷症状与心电图变化分离。其属于高危不稳定型心绞痛,应尽早行介入检查治疗,否则可能会发生严重心血...Wel ens综合征是一种与冠状动脉左前降支严重狭窄有关的心电图T波异常改变,其特征为心绞痛发作时心电图正常,而缓解后发生T波改变,即胸闷症状与心电图变化分离。其属于高危不稳定型心绞痛,应尽早行介入检查治疗,否则可能会发生严重心血管病事件。临床医生应熟悉这一特征性的心电图改变与左前降支病变致急性心肌梗死有关。展开更多
Aiming at the requirements of installation and work environment of metal-based fiber Bragg grating(FBG)sensor,a resistance spot welding method is presented.Firstly,the effect of welding parameters on welding quality i...Aiming at the requirements of installation and work environment of metal-based fiber Bragg grating(FBG)sensor,a resistance spot welding method is presented.Firstly,the effect of welding parameters on welding quality is discussed theoretically,and a suitable resistance spot welding method for the metal-based FBG sensor is proposed for the first time.Then through serial resistance spot welding tests,the feasibility and practicability of the method are verified,and optimal welding parameters for two different tested metals are obtained.Fatigue performance test validates FBG sensors installed by the proposed method with good fatigue properties and long-term stable measurement performance.The research results can provide technical guidance for engineering structure long-term safety monitoring.展开更多
Critical erosionflow rate is the key factor restricting the injection/production capacity of an injection/production well.At present,it is commonly calculated according to API RP 14E standard and its calculation resul...Critical erosionflow rate is the key factor restricting the injection/production capacity of an injection/production well.At present,it is commonly calculated according to API RP 14E standard and its calculation result tends to be conservative.So far,however,there is no definite laboratory experiment orfield data that can prove that critical erosionflow rate can be increased on the basis of API RP 14E.To deal this end,the concept of critical erosionflow rate was proposed based on corrosion rate for thefirst time in this paper.Then,a laboratory equivalent simulation experiment under real injection and production conditions was carried out by comprehensively taking into account the factors influencing string erosion(including temperature,pressure,gas component,water content,solid particle content and string material)while introducing the wall shear stress.Accordingly,the critical erosion coefficient(C)under experimental working conditions was calculated.Finally,a C value chart for three kinds of strings that are commonly used onfield(N80,SM80S and S13Cr)was established.And the following research results are ob-tained.First,solid particle content,water content,CO_(2)differential pressure and wall shear stress are the main erosion controlling factors.Second,solid particle content is the most significant factor that affects the erosion of N80,SM80S and S13Cr strings,and erosion of N80 and SM80S strings is more sensitive to wall shear stress and water content.Third,as for S13Cr string,the C value can be 100 when the solid particle content is lower than 250 mg/L,180 when thefluid contains liquid but no solid particles,and 275 when thefluid is gas phase.Fourth,as for N80 and SM80S strings,the C value can be in the range of 100e180 based on different water content and wall shear stress when thefluid contains liquid but no solid particles,and 275 when thefluid is in gas phase.Fifth,in view that thefluid produced from the injection/production wells of Hutubi gas storage has a water content of 0.0010‰without solid particles,S13Cr is adopted as string material and the C value is set at 180.It is shown in the laboratory erosion experiments that no erosion trace occurs on the string samples under injection and production conditions and the erosion rate is extremely low without point erosion.In conclusion,the C value chart established in this paper is reliable and can provide the guidance for the scientific and reasonable determination of critical erosionflow rate.展开更多
文摘Aiming at the requirements of installation and work environment of metal-based fiber Bragg grating(FBG)sensor,a resistance spot welding method is presented.Firstly,the effect of welding parameters on welding quality is discussed theoretically,and a suitable resistance spot welding method for the metal-based FBG sensor is proposed for the first time.Then through serial resistance spot welding tests,the feasibility and practicability of the method are verified,and optimal welding parameters for two different tested metals are obtained.Fatigue performance test validates FBG sensors installed by the proposed method with good fatigue properties and long-term stable measurement performance.The research results can provide technical guidance for engineering structure long-term safety monitoring.
基金supported by PetroChina Major Scientifie Research&Techno-logical Development Project"Research on Key Technologies of Injection and Production Engincering of Underground Gas Storage"(No:2015E-4004).
文摘Critical erosionflow rate is the key factor restricting the injection/production capacity of an injection/production well.At present,it is commonly calculated according to API RP 14E standard and its calculation result tends to be conservative.So far,however,there is no definite laboratory experiment orfield data that can prove that critical erosionflow rate can be increased on the basis of API RP 14E.To deal this end,the concept of critical erosionflow rate was proposed based on corrosion rate for thefirst time in this paper.Then,a laboratory equivalent simulation experiment under real injection and production conditions was carried out by comprehensively taking into account the factors influencing string erosion(including temperature,pressure,gas component,water content,solid particle content and string material)while introducing the wall shear stress.Accordingly,the critical erosion coefficient(C)under experimental working conditions was calculated.Finally,a C value chart for three kinds of strings that are commonly used onfield(N80,SM80S and S13Cr)was established.And the following research results are ob-tained.First,solid particle content,water content,CO_(2)differential pressure and wall shear stress are the main erosion controlling factors.Second,solid particle content is the most significant factor that affects the erosion of N80,SM80S and S13Cr strings,and erosion of N80 and SM80S strings is more sensitive to wall shear stress and water content.Third,as for S13Cr string,the C value can be 100 when the solid particle content is lower than 250 mg/L,180 when thefluid contains liquid but no solid particles,and 275 when thefluid is gas phase.Fourth,as for N80 and SM80S strings,the C value can be in the range of 100e180 based on different water content and wall shear stress when thefluid contains liquid but no solid particles,and 275 when thefluid is in gas phase.Fifth,in view that thefluid produced from the injection/production wells of Hutubi gas storage has a water content of 0.0010‰without solid particles,S13Cr is adopted as string material and the C value is set at 180.It is shown in the laboratory erosion experiments that no erosion trace occurs on the string samples under injection and production conditions and the erosion rate is extremely low without point erosion.In conclusion,the C value chart established in this paper is reliable and can provide the guidance for the scientific and reasonable determination of critical erosionflow rate.
