Clay or industrial wastes containing trace rare earth (RE) oxides as one of the components are used to burn cement clinker. When the total amount of RE oxides reaches 0. 2×10-4 - 2. 0×10-4 (wt), it has posit...Clay or industrial wastes containing trace rare earth (RE) oxides as one of the components are used to burn cement clinker. When the total amount of RE oxides reaches 0. 2×10-4 - 2. 0×10-4 (wt), it has positive effect on the burnability of raw meals? and the Alite content in clinker increases. However, with the addition of lan-thanide, the formation process of clinker and the distribu-tion of lanthanide in clinker are different from those of yt-trium. If the burning temperature is 1 450 C , yttrium shiws negative effect on the formation of clinker. There-fore, to improve the quality of cement clinkern, the raw meals in which yttrium content is lower and lanthanide con-tent is higher is preferable; to reduce the consumption of coal, the raw meals that yttrium content is higher is suit-able. Using raw meals containing trace RE oxides can re-duce the cost of fluorite and protect environment.展开更多
For effectively removing the water-based drilling fluid filter cake and improving interfacial cementing strength and cementing quality,a new type of cementation flushing fluid(WD-C)was developed based on the strong fl...For effectively removing the water-based drilling fluid filter cake and improving interfacial cementing strength and cementing quality,a new type of cementation flushing fluid(WD-C)was developed based on the strong flushing principle of water soluble fiber and the oxygenolysis principle of filter cake.It is composed of 0.5%WF-H fiber,2.2%WF-O oxidant,0.35%FeSO_(4),1.8%KCl,3.0%swollen powder perlite and water with its density of 1.03 g/cm^(3).This cementation flushing fluid was systematically tested and evaluated in terms of its washing efficiency on the filter cake of water-based drilling fluid and its capacity to improve the bonding strength of cementation interface.In addition,an analysis was performed of its effect on the physical-chemical characteristics and the micro-structures of interfacial cements by means of infrared spectrum(IR),scanning electron microscope(SEM)and energy dispersive X-ray detector(EDS).It is shown that the new cementation flushing fluid presents excellent washing effect on water-based drilling fluid filter cake(with washing time within 10 min).The cement particles at the cemented interface can be hydrated normally,and hydrated calcium silicate gel,Ca(OH)_(2)and rod-shaped ettringite(AFt)crystal are generated and interwoven with each other.In this way,dense network structures are formed,so the bonding strength of the second cementing interface rises significantly,and then cementing quality is improved.Based on the research results,one more technology is set up for removing the water-based drilling fluid filter cake efficiently and improving the bonding strength of the second cementing interface.展开更多
We developed a novel cement evaluation logging tool,named the azimuthally acoustic bond tool（AABT）,which uses a phased-arc array transmitter with azimuthal detection capability.We combined numerical simulations and ...We developed a novel cement evaluation logging tool,named the azimuthally acoustic bond tool（AABT）,which uses a phased-arc array transmitter with azimuthal detection capability.We combined numerical simulations and field tests to verify the AABT tool.The numerical simulation results showed that the radiation direction of the subarray corresponding to the maximum amplitude of the first arrival matches the azimuth of the channeling when it is behind the casing.With larger channeling size in the circumferential direction,the amplitude difference of the casing wave at different azimuths becomes more evident.The test results showed that the AABT can accurately locate the casing collars and evaluate the cement bond quality with azimuthal resolution at the casing-cement interface,and can visualize the size,depth,and azimuth of channeling.In the case of good casingcement bonding,the AABT can further evaluate the cement bond quality at the cementformation interface with azimuthal resolution by using the amplitude map and the velocity of the formation wave.展开更多
Ultrasonic leaky Lamb waves are sensitive to defects and debonding in multilayer media. In this study, we use the finite-difference method to simulate the response of flexural waves in the presence of defects owing to...Ultrasonic leaky Lamb waves are sensitive to defects and debonding in multilayer media. In this study, we use the finite-difference method to simulate the response of flexural waves in the presence of defects owing to casing corrosion and rough fluctuations at the cement-formation interface. The ultrasonic obliquely incidence could effectively stimulate the flexural waves. The defects owing to casing corrosion change the amplitude of the early- arrival flexural wave, which gradually decrease with increasing defect thickness on the exterior walls and is the lowest when the defect length and wavelength were comparable. The scattering at the defects decreases the energy of flexural waves in the casing that leaks directly to fluids. For rough cement-formation interface, the early-arrival flexural waves do not change, whereas the late-arrival flexural waves have reduced amplitude owing to the scattering at rough interface.展开更多
Cement bond model wells （1：10 scaled-down） were made with a gradually degrading cement annulus for cement bond evaluation of the first interface （between the casing and the cement annulus） and the second interfa...Cement bond model wells （1：10 scaled-down） were made with a gradually degrading cement annulus for cement bond evaluation of the first interface （between the casing and the cement annulus） and the second interface （between the cement annulus and the formation）. Experimental simulation on cement bond logging was carried out with these model wells. The correlation of acoustic waveforms, casing wave energy and flee casing area before and after cement bonding of the second interface was established. The experimental results showed that the arrival of the casing waves had no relationship with the cement bonding of the second interface, but the amplitude of the casing head wave decreased obviously after the second interface was bonded. So, cement bonding of the second interface had little effect on the evaluation of the cement bond quality of the first interface by using casing head wave arrivals. Strong cement annulus waves with early arrivals were observed before the second interface was bonded, while obvious ＂formation waves＂ instead of cement annulus waves were observed after the second interface was bonded.展开更多
In liner cementing,the upper cement plug and inner components of a common hanger needs to be drilled out after cementing,which will result in a poor cementing quality or even gas leakage at the flare opening.Therefore...In liner cementing,the upper cement plug and inner components of a common hanger needs to be drilled out after cementing,which will result in a poor cementing quality or even gas leakage at the flare opening.Therefore,a new packer-type drilling-free liner hanger has been developed,and a hydraulic setting-control packer,a flexible drilling-free seal box,and an auxiliary bearing back-off mechanism that go with the line hanger have been designed at the same time.Specific operation procedures include:(1)run in the liner string to the designed depth,then fully circulate the drilling fluid,finally drop the ball.When the tripping ball gets into the seat,the pressure will go up to cut off the hanging control pin and set the hanger;(2)continue to hold the pressure and cut off the ball seat pin to form circulation;(3)trip in the drill pipe to exert pressure on the hanger,back off to release the hanger from the running tool;(4)lower the drill pipe plug upon the completion of cement in-jection,cut off the releasing control pin of hollow casing plug,and run down further to bump with the bumping assembly;(5)remove the cementing head and connect the kelly driver,hold pressure again,then slowly pull up the drill tools,exert hydraulic pressure on the setting hydraulic cylinder of the packer assembly to cut off the setting control pin and set the packer;and(6)pull up the tools to the flare opening and wash out excessive cement slurry by circulating to realize free drilling of the whole hole.The successful application of the liner hanger in 127 mm diameter liner in Well BQ203-H1 indicates that the packer-type liner hanger has such advantages as easy hanging and back-off,accurate bumping,simple setting,and sound sealing performance.展开更多
Coalbeds are characterized by high organic matter content,presence of joints and smooth joint surface,which lead to weak bonding between coal and set cement and poor cementing quality of coalbeds,and consequently the ...Coalbeds are characterized by high organic matter content,presence of joints and smooth joint surface,which lead to weak bonding between coal and set cement and poor cementing quality of coalbeds,and consequently the economic and effective development of coalbed methane(CBM)is restricted seriously.In this paper,components,compositions and wetting characteristics of coal were analyzed in order to improve the water wettability of coal,the effects of different surfactants and their concentration and soaking time on the surface wetting angle of coal and interfacial bonding strength were tested and measured.The high-efficiency hydrophilic wettability modifier was optimized.The strengthened coalbed bonding prepad fluid system was developed and applied practically in the Qinshui Basin,Shanxi province.The results of laboratory tests and field applications show that the compact adsorption of surfactant containing ether and sulfate radical on the surface of coal can convert the surface wettability into strong hydrophilicity at the concentration of 0.3%within 30 s,thus improving significantly the interface bonding strength(up to 65.5%)between coal and set cement.The field application in CBM well cementing shows that the strengthened coalbed bonding prepad fluid can improve the cementing quality from unqualified level to high level,and play a significant role in improving CBM hole interval cementing quality.It is concluded that this technology provides an effective guarantee for coalbed cementing quality improvement and smooth implementation of stimulation measures like fracturing.展开更多
Cement bond quality evaluations are essential for assessing zonal isolation between formation strata,providing crucial information for ensuring environmental and ecological safety in oil and gas exploitation,geotherma...Cement bond quality evaluations are essential for assessing zonal isolation between formation strata,providing crucial information for ensuring environmental and ecological safety in oil and gas exploitation,geothermal energy injection and geological carbon dioxide sequestration.In the past decade,the ultrasonic pulse-echo and pitch-catch logging techniques have emerged as effective and non-destructive methods for quantitatively eval-uating bond quality at both the casing-cement and cement-formation interfaces.This review presents a comprehensive overview of recent advancements in cement bond quality assessment based on ultrasonic mea-surements.Key developments include automatic waveform quality assessment,inversion techniques for mud and cement impedance,tool trajectory corrections,separation of flexural and extensional mode waves,machine learning-based extraction and enhancement of TIE waveforms,and imaging of the cement-formation interface using the reverse time migration approach.The review thoroughly explores the methodological principles and applications of these techniques,supported by synthetic datasets,full-scale physical well experiments,and field well data.Considering the recent progress in machine learning and the growing availability of advanced computational resources,we highlight the most significant achievements and ongoing challenges in data pro-cessing,while discussing the potential advancements these techniques could offer in the near future.展开更多
High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth ...High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth detection. Full waveforms reflected from the cased hole are simulated for different bonding conditions by the generalized transfer matrix method. Because of the high acoustic impedance of casing, the amplitudes of the reflected waves from the cement and the formation are small and cannot easily be used to evaluate the cementing condition. The wave that can propagate into the cement and the formation through the casing concentrates closely on the casing resonant frequency. To reduce the amplitude of the reflected wave from the casing inner surface and highlight the part of the reflected wave which carries the cementing quality information, the reflected full wave is filtered according to the casing resonant frequency. There are several wave packets in the filtered waveform. When the amplitude of the second wave packet is low, the cement bonds well with the casing, otherwise poorly. A low amplitude third wave packet is an indication of a good bond of the cement with the formation, otherwise poor. To reveal the sensitivity of the reflection wave amplitudes to the incident angle, reflected full waveform is modeled when an acoustic beam with finite width is incident on the casing. It is shown that the bond evaluation method based on filtered wave packets is valid for incident angle less than 5 degrees.展开更多
In this paper, it is presented that an approach based on Continuous Wavelet Thansform(CWT) and Fourier Transform(FT) for identifying ultrasonic echoes in inspecting oil well cementing quality. First, CWT is used to pr...In this paper, it is presented that an approach based on Continuous Wavelet Thansform(CWT) and Fourier Transform(FT) for identifying ultrasonic echoes in inspecting oil well cementing quality. First, CWT is used to process echo signals. Then spectra of the processing results in some specilic scale-time segments are calculated as pattern features. The research results show that theoretical calculations basically agree with experimental results. Compared with the aPproach based on the spectra or Discrete Wavlet Transform, our approach has advantages of fine analyzing scales, stable features and high recognizing rate. It is very suitable to identify echo signals whose spectra vary with time.展开更多
Slip boundary condition is commonly utilized to model elastic wave propagation through layered earth media. The same approach is used here to characterize acoustic wave propagation along a cased borehole with various ...Slip boundary condition is commonly utilized to model elastic wave propagation through layered earth media. The same approach is used here to characterize acoustic wave propagation along a cased borehole with various cement bond conditions. By modeling the cement layer between casing and formation as a viscoelastic slip interface with complex coupling rigidity parameters, one can not only reduce the complexity in the classical elastic wave modeling of the problem, but also efficiently model various complicated wave phenomena that are difficult for the existing modeling. More specifically, the new theory can well describe the effect of the cement bond condition change and the location of the change(i.e., whether it is in the first interface between casing and cement, or the second interface between cement and formation) on the acoustic waves,demonstrating the good modeling capability and predicting power. Application of the theory to field data shows that the theory can correctly model the acoustic wave characteristics and interpret the cement bond condition, thus providing a useful fundament theory for casing bond evaluation using acoustic logging.展开更多
基金Sapported by the National Natural Science Foundation of China(No. 2977012)
文摘Clay or industrial wastes containing trace rare earth (RE) oxides as one of the components are used to burn cement clinker. When the total amount of RE oxides reaches 0. 2×10-4 - 2. 0×10-4 (wt), it has positive effect on the burnability of raw meals? and the Alite content in clinker increases. However, with the addition of lan-thanide, the formation process of clinker and the distribu-tion of lanthanide in clinker are different from those of yt-trium. If the burning temperature is 1 450 C , yttrium shiws negative effect on the formation of clinker. There-fore, to improve the quality of cement clinkern, the raw meals in which yttrium content is lower and lanthanide con-tent is higher is preferable; to reduce the consumption of coal, the raw meals that yttrium content is higher is suit-able. Using raw meals containing trace RE oxides can re-duce the cost of fluorite and protect environment.
基金Supported by National Natural Science Foundation of China(Grand No.51174226)National Science and Technology Major Project(Grand No.2009ZX05060)。
文摘For effectively removing the water-based drilling fluid filter cake and improving interfacial cementing strength and cementing quality,a new type of cementation flushing fluid(WD-C)was developed based on the strong flushing principle of water soluble fiber and the oxygenolysis principle of filter cake.It is composed of 0.5%WF-H fiber,2.2%WF-O oxidant,0.35%FeSO_(4),1.8%KCl,3.0%swollen powder perlite and water with its density of 1.03 g/cm^(3).This cementation flushing fluid was systematically tested and evaluated in terms of its washing efficiency on the filter cake of water-based drilling fluid and its capacity to improve the bonding strength of cementation interface.In addition,an analysis was performed of its effect on the physical-chemical characteristics and the micro-structures of interfacial cements by means of infrared spectrum(IR),scanning electron microscope(SEM)and energy dispersive X-ray detector(EDS).It is shown that the new cementation flushing fluid presents excellent washing effect on water-based drilling fluid filter cake(with washing time within 10 min).The cement particles at the cemented interface can be hydrated normally,and hydrated calcium silicate gel,Ca(OH)_(2)and rod-shaped ettringite(AFt)crystal are generated and interwoven with each other.In this way,dense network structures are formed,so the bonding strength of the second cementing interface rises significantly,and then cementing quality is improved.Based on the research results,one more technology is set up for removing the water-based drilling fluid filter cake efficiently and improving the bonding strength of the second cementing interface.
基金supported by the National Natural Science Foundation of China(Nos.11204380,11374371,61102102,and11134011)National Science and Technology Major Project(No.2011ZX05020-009)+1 种基金China National Petroleum Corporation(Nos.2014B-4011,2014D-4105,and 2014A-3912)PetroChina Innovation Foundation(No.2014D-5006-0307)
文摘We developed a novel cement evaluation logging tool,named the azimuthally acoustic bond tool（AABT）,which uses a phased-arc array transmitter with azimuthal detection capability.We combined numerical simulations and field tests to verify the AABT tool.The numerical simulation results showed that the radiation direction of the subarray corresponding to the maximum amplitude of the first arrival matches the azimuth of the channeling when it is behind the casing.With larger channeling size in the circumferential direction,the amplitude difference of the casing wave at different azimuths becomes more evident.The test results showed that the AABT can accurately locate the casing collars and evaluate the cement bond quality with azimuthal resolution at the casing-cement interface,and can visualize the size,depth,and azimuth of channeling.In the case of good casingcement bonding,the AABT can further evaluate the cement bond quality at the cementformation interface with azimuthal resolution by using the amplitude map and the velocity of the formation wave.
基金supported by the Research and Development of Key Instruments and Technologies for Deep Resources Prospecting(No.ZDYZ2012-1-07)the National Natural Science Foundation of China(Nos.41204099,11134011,and 11274341)
文摘Ultrasonic leaky Lamb waves are sensitive to defects and debonding in multilayer media. In this study, we use the finite-difference method to simulate the response of flexural waves in the presence of defects owing to casing corrosion and rough fluctuations at the cement-formation interface. The ultrasonic obliquely incidence could effectively stimulate the flexural waves. The defects owing to casing corrosion change the amplitude of the early- arrival flexural wave, which gradually decrease with increasing defect thickness on the exterior walls and is the lowest when the defect length and wavelength were comparable. The scattering at the defects decreases the energy of flexural waves in the casing that leaks directly to fluids. For rough cement-formation interface, the early-arrival flexural waves do not change, whereas the late-arrival flexural waves have reduced amplitude owing to the scattering at rough interface.
基金supported by the National Natural Science Foundation of China(Grant No.10534040 and No.40574049)key laboratory of well logging of China National Petroleum Corporation(CNPC).
文摘Cement bond model wells （1：10 scaled-down） were made with a gradually degrading cement annulus for cement bond evaluation of the first interface （between the casing and the cement annulus） and the second interface （between the cement annulus and the formation）. Experimental simulation on cement bond logging was carried out with these model wells. The correlation of acoustic waveforms, casing wave energy and flee casing area before and after cement bonding of the second interface was established. The experimental results showed that the arrival of the casing waves had no relationship with the cement bonding of the second interface, but the amplitude of the casing head wave decreased obviously after the second interface was bonded. So, cement bonding of the second interface had little effect on the evaluation of the cement bond quality of the first interface by using casing head wave arrivals. Strong cement annulus waves with early arrivals were observed before the second interface was bonded, while obvious ＂formation waves＂ instead of cement annulus waves were observed after the second interface was bonded.
基金2011 Overall Project of China National Petroleum Corpo-ration(No.2011T-0501).
文摘In liner cementing,the upper cement plug and inner components of a common hanger needs to be drilled out after cementing,which will result in a poor cementing quality or even gas leakage at the flare opening.Therefore,a new packer-type drilling-free liner hanger has been developed,and a hydraulic setting-control packer,a flexible drilling-free seal box,and an auxiliary bearing back-off mechanism that go with the line hanger have been designed at the same time.Specific operation procedures include:(1)run in the liner string to the designed depth,then fully circulate the drilling fluid,finally drop the ball.When the tripping ball gets into the seat,the pressure will go up to cut off the hanging control pin and set the hanger;(2)continue to hold the pressure and cut off the ball seat pin to form circulation;(3)trip in the drill pipe to exert pressure on the hanger,back off to release the hanger from the running tool;(4)lower the drill pipe plug upon the completion of cement in-jection,cut off the releasing control pin of hollow casing plug,and run down further to bump with the bumping assembly;(5)remove the cementing head and connect the kelly driver,hold pressure again,then slowly pull up the drill tools,exert hydraulic pressure on the setting hydraulic cylinder of the packer assembly to cut off the setting control pin and set the packer;and(6)pull up the tools to the flare opening and wash out excessive cement slurry by circulating to realize free drilling of the whole hole.The successful application of the liner hanger in 127 mm diameter liner in Well BQ203-H1 indicates that the packer-type liner hanger has such advantages as easy hanging and back-off,accurate bumping,simple setting,and sound sealing performance.
文摘Coalbeds are characterized by high organic matter content,presence of joints and smooth joint surface,which lead to weak bonding between coal and set cement and poor cementing quality of coalbeds,and consequently the economic and effective development of coalbed methane(CBM)is restricted seriously.In this paper,components,compositions and wetting characteristics of coal were analyzed in order to improve the water wettability of coal,the effects of different surfactants and their concentration and soaking time on the surface wetting angle of coal and interfacial bonding strength were tested and measured.The high-efficiency hydrophilic wettability modifier was optimized.The strengthened coalbed bonding prepad fluid system was developed and applied practically in the Qinshui Basin,Shanxi province.The results of laboratory tests and field applications show that the compact adsorption of surfactant containing ether and sulfate radical on the surface of coal can convert the surface wettability into strong hydrophilicity at the concentration of 0.3%within 30 s,thus improving significantly the interface bonding strength(up to 65.5%)between coal and set cement.The field application in CBM well cementing shows that the strengthened coalbed bonding prepad fluid can improve the cementing quality from unqualified level to high level,and play a significant role in improving CBM hole interval cementing quality.It is concluded that this technology provides an effective guarantee for coalbed cementing quality improvement and smooth implementation of stimulation measures like fracturing.
基金supported by a National Natural Science Foundation of China(Grant numbers 42474167,41974150,42174158,W2522002)Natural Science Basic Research Program of Shaanxi(2023-JC-YB-220)the Shenzhen Science and Technology Program(grant numbers JCYJ20230807120007015 and RCJC20231211085916003).
文摘Cement bond quality evaluations are essential for assessing zonal isolation between formation strata,providing crucial information for ensuring environmental and ecological safety in oil and gas exploitation,geothermal energy injection and geological carbon dioxide sequestration.In the past decade,the ultrasonic pulse-echo and pitch-catch logging techniques have emerged as effective and non-destructive methods for quantitatively eval-uating bond quality at both the casing-cement and cement-formation interfaces.This review presents a comprehensive overview of recent advancements in cement bond quality assessment based on ultrasonic mea-surements.Key developments include automatic waveform quality assessment,inversion techniques for mud and cement impedance,tool trajectory corrections,separation of flexural and extensional mode waves,machine learning-based extraction and enhancement of TIE waveforms,and imaging of the cement-formation interface using the reverse time migration approach.The review thoroughly explores the methodological principles and applications of these techniques,supported by synthetic datasets,full-scale physical well experiments,and field well data.Considering the recent progress in machine learning and the growing availability of advanced computational resources,we highlight the most significant achievements and ongoing challenges in data pro-cessing,while discussing the potential advancements these techniques could offer in the near future.
基金supported by the National Natural Science Foundation of China(41174110,41204092)
文摘High cement bond quality is required to keep an oil well from hydraulic commu- nication between zones. In the cement bond evaluation, the ultrasonic echo method is widely used for its capability of channeling azimuth detection. Full waveforms reflected from the cased hole are simulated for different bonding conditions by the generalized transfer matrix method. Because of the high acoustic impedance of casing, the amplitudes of the reflected waves from the cement and the formation are small and cannot easily be used to evaluate the cementing condition. The wave that can propagate into the cement and the formation through the casing concentrates closely on the casing resonant frequency. To reduce the amplitude of the reflected wave from the casing inner surface and highlight the part of the reflected wave which carries the cementing quality information, the reflected full wave is filtered according to the casing resonant frequency. There are several wave packets in the filtered waveform. When the amplitude of the second wave packet is low, the cement bonds well with the casing, otherwise poorly. A low amplitude third wave packet is an indication of a good bond of the cement with the formation, otherwise poor. To reveal the sensitivity of the reflection wave amplitudes to the incident angle, reflected full waveform is modeled when an acoustic beam with finite width is incident on the casing. It is shown that the bond evaluation method based on filtered wave packets is valid for incident angle less than 5 degrees.
文摘In this paper, it is presented that an approach based on Continuous Wavelet Thansform(CWT) and Fourier Transform(FT) for identifying ultrasonic echoes in inspecting oil well cementing quality. First, CWT is used to process echo signals. Then spectra of the processing results in some specilic scale-time segments are calculated as pattern features. The research results show that theoretical calculations basically agree with experimental results. Compared with the aPproach based on the spectra or Discrete Wavlet Transform, our approach has advantages of fine analyzing scales, stable features and high recognizing rate. It is very suitable to identify echo signals whose spectra vary with time.
基金supported by the National Natural Science Foundation of China (Grant No. 41774141)
文摘Slip boundary condition is commonly utilized to model elastic wave propagation through layered earth media. The same approach is used here to characterize acoustic wave propagation along a cased borehole with various cement bond conditions. By modeling the cement layer between casing and formation as a viscoelastic slip interface with complex coupling rigidity parameters, one can not only reduce the complexity in the classical elastic wave modeling of the problem, but also efficiently model various complicated wave phenomena that are difficult for the existing modeling. More specifically, the new theory can well describe the effect of the cement bond condition change and the location of the change(i.e., whether it is in the first interface between casing and cement, or the second interface between cement and formation) on the acoustic waves,demonstrating the good modeling capability and predicting power. Application of the theory to field data shows that the theory can correctly model the acoustic wave characteristics and interpret the cement bond condition, thus providing a useful fundament theory for casing bond evaluation using acoustic logging.
