With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various complicatio...With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various complications.Currently,reagents based on modified natural polymers(which are naturally occurring compounds)and synthetic polymers(SPs)which are polymeric compounds created industrially,are widely used to prevent emerging complications in the drilling process.However,compared to modified natural polymers,SPs form a family of high-molecular-weight compounds that are fully synthesized by undergoing chemical polymerization reactions.SPs provide substantial flexibility in their design.Moreover,their size and chemical composition can be adjusted to provide properties for nearly all the functional objectives of drilling fluids.They can be classified based on chemical ingredients,type of reaction,and their responses to heating.However,some of SPs,due to their structural characteristics,have a high cost,a poor temperature and salt resistance in drilling fluids,and degradation begins when the temperature reaches 130℃.These drawbacks prevent SP use in some medium and deep wells.Thus,this review addresses the historical development,the characteristics,manufacturing methods,classification,and the applications of SPs in drilling fluids.The contributions of SPs as additives to drilling fluids to enhance rheology,filtrate generation,carrying of cuttings,fluid lubricity,and clay/shale stability are explained in detail.The mechanisms,impacts,and advances achieved when SPs are added to drilling fluids are also described.The typical challenges encountered by SPs when deployed in drilling fluids and their advantages and drawbacks are also discussed.Economic issues also impact the applications of SPs in drilling fluids.Consequently,the cost of the most relevant SPs,and the monomers used in their synthesis,are assessed.Environmental impacts of SPs when deployed in drilling fluids,and their manufacturing processes are identified,together with advances in SP-treatment methods aimed at reducing those impacts.Recommendations for required future research addressing SP property and performance gaps are provided.展开更多
μEDM(micro-electrical discharge machining)is a process for machining conductive materials without mechanical contact;it is particularly suitable for machining hard materials.The principle consists in creating electri...μEDM(micro-electrical discharge machining)is a process for machining conductive materials without mechanical contact;it is particularly suitable for machining hard materials.The principle consists in creating electrical discharges between a micro-tool and a workpiece,both of which are immersed in a dielectric.It is a complementary process to mechanical,laser,micro-machining techniques,and even to techniques derived from silicon microtechnology(RIE,DRIE,LIGA).However,the resolution ofμEDM is limited;it depends on several electrical and physical parameters.The goal of this paper is to characterize the holes obtained by drilling usingμEDM with different micro-tool diameters(Φ=250μm;Φ=80μm;Φ=40μm;Φ=20μm)for an experimental time of t=2 h.The results obtained let us conclude that a large diameter micro-tool(Φ=250μm)leads to removing a larger amount of material(43×10^(5)μm^(3))than small diameters:Φ=80μm;Φ=40μm;Φ=20μm where the removed volume is equal to 2.6×10^(5)μm^(3);105μm^(3);0.4×10^(5)μm^(3),respectively.The electrode-tool diameter influences the maximum depth of the holes;a diameter ofΦ=250μm generates a hole where the maximum depth is 170μm while small diameters:Φ=80μm;Φ=40μm;Φ=20μm provide holes with a depth of 82μm;51μm;50μm respectively.Through these experiments,we can also conclude that the lateral gap of the holes is almost constant.It is about 40μm whatever the diameter.展开更多
Force analysis using a compact tension model, as recommended by ASTM, was carried out on a crack stop hole. The stress before, and after, drilling the hole was compared in terms of stress concentration and stress grad...Force analysis using a compact tension model, as recommended by ASTM, was carried out on a crack stop hole. The stress before, and after, drilling the hole was compared in terms of stress concentration and stress gradient. The optimum drilling location and diameter were studied through analysis of different locations and diameters. By analyzing the effects of flank holes and an additional hole, drilling advice was proposed and fatigue testing of the cracks in a steel bridge deck with a crack stop hole was conducted. The results show that the stress at the crack tip with a crack stop hole decreased, and the major principal stress around the hole was distributed accordingly. The optimum position of the crack stop hole centre was where the centre of the crack stop hole was situated behind the crack and the hole edge coincided with the crack tip. Therefore, hole diameters larger than 8 mm, or those weakening the section by 10%, were suggested as the best diameters. In terms of multi-hole crack stopping, a flank hole was not recommended. The optimum horizontal position of flank holes was at a distance of 1/4 of a single hole diameter from, and in front of, the single hole. Besides, the experiment showed that crack stop hole could only prevent cracks from growing and had no influence on crack growth rate.展开更多
Revolution radius is one of the significant parameters in orbital drilling,which has great influence on many factors,such as the cutting area of front and side cutting edge,undeformed chip geometry,delamination and bu...Revolution radius is one of the significant parameters in orbital drilling,which has great influence on many factors,such as the cutting area of front and side cutting edge,undeformed chip geometry,delamination and burr at hole exit side,hole surface roughness,cutting tool force and deflection,chip removal and heat transmission.First,the influence of revolution radius on the factors is discussed theoretically in detail.Analysis results show that big revolution radius can reduce axial cutting force,restrain exit delamination and burr,and improve chip removal and heat transmission.Then,single factor test and orthogonal test are utilized in the two processing methods as machining unidiameter holes with several cutting tools and machining different diameter holes with one tool.Finally,the influence of revolution radius on cutting force and hole machining precision is studied.These results provide a profound foundation for future optimization of cutting control parameters.展开更多
The ages of coral reef samples from several shallow drill holes in the South China Sea are determined by ESR and U-series (230Th/234U) methods. The experimental results show ideal agreement between ESR and U-series ag...The ages of coral reef samples from several shallow drill holes in the South China Sea are determined by ESR and U-series (230Th/234U) methods. The experimental results show ideal agreement between ESR and U-series ages and that the coral reefs were formed in the early Holocene. In the determination of natural total dose of coral reef by use of the additive dose method good results can be obtained by exponential fitting, no matter how the effect of dose saturation is. It was found that the ratio of the natural ESR signal intensity ( I0) to the ESR signal intensity at dose saturation ( Imax) of sample can reflect the significance of a irradiation efficiency-k value. Using the k value of sample determined by the formula given in this paper, the precision of ESR dating of marine carbonates can be improved.展开更多
A possibility of the efficient use of rotary percussive drilling to provide drilling smaller diameter holes(40–70 mm) both in mining and prospecting is disclosed herein. A new construction designed for the nipple thr...A possibility of the efficient use of rotary percussive drilling to provide drilling smaller diameter holes(40–70 mm) both in mining and prospecting is disclosed herein. A new construction designed for the nipple thread connection is described. The relative amplitude variation, change of power pulse time and energy in their propagation throughout the drilling tool are determined. A possibility of the efficient power pulse transfer along the drill string to the rock destruction tools with new nipple connections which allow automating the make-up and breakout system of drill pipe was supported by experiments.展开更多
With special drilling operation equipment and specific conditions of geology, how does drilling fluid carry cuttings effectively? So far, it is still an urgent problem for drilling researchers to study. This work just...With special drilling operation equipment and specific conditions of geology, how does drilling fluid carry cuttings effectively? So far, it is still an urgent problem for drilling researchers to study. This work just aims at the actual engineering background to develop studying model. In this paper, according to non Newtonian fluid mechanics, the law of the solid liquid, two phase fluid flow and actual drilling engineering, the major factors affecting cuttings transport are drilling fluid velocity, hole inclination and fluid rheological properties. Getting a clear understanding of the law of drilling fluid and its cutting taking mechanism, this paper puts forward a model for analysis of field data and quantitative forecast of cutting taking capability of drilling fluid. The full scale annular test section was 6.1 m with 76 and 114 mm drillpipe in a 203 mm ID (wellbore diameter). Hole angle varied from 0° to 90°.展开更多
Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss p...Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss produced by multi-beam parabolic antenna.Based on 3-D printing technique,Luneburg lens antennas by drilling holes are studied.Permittivity and loss tangent of the equivalent lens materials can be influenced by original materials,hole shapes,hole directions,and porosity.After tests,polystyrene with waxes may be the most appropriate materials for Luneburg lens with high strength.Permittivity with the shape of triangle is the lowest due to the homogeneity.Relative permittivities with the direction at a range of 15°-45°are lower while loss tangent at a range of 0°-30°.Radial directional holes are more appropriate for Luneburg lens.The relative permittivity is decreased with the increment of porosity.After calculations,the forecasts calculated by Looyenga and A-BG theory are more precise.Finally,Luneburg lens with two layers is fabricated by 3-D printing.展开更多
Manufacturing accuracy, especially position accuracy of fastener holes, directly affects service life and security of aircraft. The traditional modification has poor robustness, while the modification based on laser t...Manufacturing accuracy, especially position accuracy of fastener holes, directly affects service life and security of aircraft. The traditional modification has poor robustness, while the modification based on laser tracker costs too much. To improve the relative position accuracy of aircraft assembly drilling, and ensure the hole-edge distance requirement, a method was presented to modify the coordinates of drilling holes. Based on online inspecting two positions of pre-assembly holes and their theoretical coordinates, the spatial coordinate transformation matrix of modification could be calculated. Thus the straight drilling holes could be modified. The method improves relative position accuracy of drilling on simple structure effectively. And it reduces the requirement of absolute position accuracy and the cost of position modification. And the process technician also can use this method to decide the position accuracy of different pre-assembly holes based on the accuracy requirement of assembly holes.展开更多
With the innovation and development of offshore oil drilling technology, drilling wells in deep waters areas have become an important activity for the development of new hydrocarbon reservoirs in this type of environm...With the innovation and development of offshore oil drilling technology, drilling wells in deep waters areas have become an important activity for the development of new hydrocarbon reservoirs in this type of environment. CNOOC (China National Offshore Oil Corporation) won the rights to exploit two unexplored deepwater blocks in the Gulf of Mexico, in a bid realized by the Mexican Government (CNH), in 2016. The challenge to combine the newest technology with the oil industry experienced knowledge to lead the exploration and development of these deep-water blocks in Mexico is around the corner. Therefore, the basic techniques for deep waters wells drilling and the main potential risks are expounded in this paper. A set of deep waters wells drilling processes and methodologies are previously designed, and a specific case is demonstrated next, which provides a referential model for deep waters wells drilling in the Gulf of Mexico.展开更多
Based on the content of radioactive elements (U, Th, K) of strata in two drill holes in the Fuzhou basin, and combined with the result of spore_pollen analysis, the relationship between radioactivity and lithology and...Based on the content of radioactive elements (U, Th, K) of strata in two drill holes in the Fuzhou basin, and combined with the result of spore_pollen analysis, the relationship between radioactivity and lithology and deposit environments is discussed and the results show that the content of radioactive substances is related to the granularity and lithology in sediment, and it is higher in argillaceous sediment (e.g. silt and clay), lower in sand sediment and in the middle in gravels between the above two kinds of sediment. The content of radioactive substances is also related to paleoclimate. A warm and humid environment is propitious to the deposition of radioactive substances, while a cool and dry climate is just the reverse.展开更多
Enhancement of technology and techniques for drilling deep directed oil and gas bore hole is one of the most important problems of the current petroleum industry.Not infrequently, the drilling of these bore holes is a...Enhancement of technology and techniques for drilling deep directed oil and gas bore hole is one of the most important problems of the current petroleum industry.Not infrequently, the drilling of these bore holes is attended by occurrence of extraordinary situations associated with technical accidents. Among these is the Eulerian loss of stability of a drill string in the channel of a curvilinear bore hole. Methods of computer simulation should play a dominant role in prediction of these states. In this paper, a new statement of the problem of critical buckling of the drill strings in 3D curvilinear bore holes is proposed. It is based on combined use of the theory of curvilinear elastic rods, Eulerian theory of stability, theory of channel surfaces, and methods of classical mechanics of systems with nonlinear constraints. It is noted that the stated problem is singularly perturbed and its solutions have the shapes of localized harmonic wavelets. The calculation results showed that the friction effects lead to essential redistribution of internal axial forces, as well as changing the eigenmode shapes and sites of their localization. These features make the buckling phenomena less predictable and raise the role of computer simulation of these effects.展开更多
Study of micro-area chemical compositions indicates that phengite in albite gneiss from hole ZK2304 of the Donghai region has evident compositional zoning. SiO2 and tetrahedrally coordinated Si contents decrease, and ...Study of micro-area chemical compositions indicates that phengite in albite gneiss from hole ZK2304 of the Donghai region has evident compositional zoning. SiO2 and tetrahedrally coordinated Si contents decrease, and Al2O3, AlIVand AlVIcontents increase gradually from core to rim. However, K2O, MgO and FeO contents basically remain unchanged from core to rim. According to P-T estimates obtained from geothermometers and barometers, combined with previous experimental data, the core belt (micro-area I) of phengite was formed at T=637–672°C and P=1.55–1.73 GPa, and the transitional belt (micro-area II) of the phengite were formed at T=594–654°C and P=1.35–1.45 GPa. Towards the rim belt (micro-area III), the temperature decreased slightly, but the pressure decreased rapidly with T=542–630°C and P=1.12–1.19 GPa. The P-T evolution path recorded by the compositional zoning of phengite is characterized by significant near-isothermal decompression, revealing that the gneiss has undergone high-pressure-ultrahigh-pressure metamorphism. The compositional zoning of the phengite in the albite gneiss may have formed in the geodynamic process of rapid exhumation in the Sulu ultrahigh-pressure metamorphic belt.展开更多
Foam drilling is increasingly used to develop low pressure reservoirs or highly depleted mature reservoirs because of minimizing the formation damage and potential hazardous drilling problems. Prediction of the cuttin...Foam drilling is increasingly used to develop low pressure reservoirs or highly depleted mature reservoirs because of minimizing the formation damage and potential hazardous drilling problems. Prediction of the cuttings concentration in the wellbore annulus as a function of operational drilling parameters such as wellbore geometry, pumping rate, drilling fluid rheology and density and maximum drilling rate is very important for optimizing these parameters. This paper describes a simple and more reliable artificial neural network (ANN) method and multiple linear regression (MLR) to predict cuttings concentration during foam drilling operation. This model is applicable for various borehole conditions using some critical parameters associated with foam velocity, foam quality, hole geometry, subsurface condition (pressure and temperature) and pipe rotation. The average absolute percent relative error (AAPE) between the experimental cuttings concentration and ANN model is less than 6%, and using MLR, AAPE is less than 9%. A comparison of the ANN and mechanistic model was done. The AAPE values for all datasets in this study were 3.2%, 8.5% and 10.3% for ANN model, MLR model and mechanistic model respectively. The results show high ability of ANN in prediction with respect to statistical methods.展开更多
Efficient cuttings transport and improving rate of penetration(ROP)are two major challenges in horizontal drilling and extended reach drilling.A type of jet mill bit(JMB)may provide an opportunity to catch the two bir...Efficient cuttings transport and improving rate of penetration(ROP)are two major challenges in horizontal drilling and extended reach drilling.A type of jet mill bit(JMB)may provide an opportunity to catch the two birds with one stone:not only enhancing cuttings transport efficiency but also improving ROP by depressuring at the bottom hole.In this paper,the JMB is further improved and a new type of depressure-dominated JMB is presented;meanwhile,the depressurization capacity of the depressure-dominated JMB is investigated by numerical simulation and experiment.The numerical study shows that low flow-rate ratio helps to enhance the depressurization capacity of the depressure-dominated JMB;for both depressurization and bottom hole cleaning concern,the flow-rate ratio is suggested to be set at approximately 1:1.With all other parameter values being constant,lower dimensionless nozzle-to-throat-area ratio may result in higher depressurization capacity and better bottom hole cleaning,and the optimal dimensionless nozzle-to-throat-area ratio is at approximately0.15.Experiments also indicate that reducing the dimensionless flow-rate ratio may help to increase the depressurization capacity of the depressure-dominated JMB.This work provides drilling engineers with a promising tool to improve ROP.展开更多
The hole-drilling method is one of the most wellknown methods for measuring residual stresses. To identify unknown plane stresses in a specimen, a circular hole is first drilled in the infinite plate under plane stres...The hole-drilling method is one of the most wellknown methods for measuring residual stresses. To identify unknown plane stresses in a specimen, a circular hole is first drilled in the infinite plate under plane stress, then the strains resulting from the hole drilling is measured. The strains may be acquired from interpreting the Moire signature around the hole. In crossed grating Moire interferometry, the horizontal and vertical displacement fields (u and v) can be obtained to determinate two strain fields and one shearing strain field. In this paper, by means of Moire interferometry and three directions grating (grating rosette) developed by the authors, three displacement fields (u, v and s) are obtained to acquire three strain fields. As a practical application, the hole-drilling method is adopted to measure the relief strains for aluminum and fiber reinforced composite. It is a step by step method; in each step a single laminate or equivalent depth is drilled to find some relationships between the drilling depth and the residual strains relieved in the fiber reinforced composite materials.展开更多
The stability and nonlinear dynamic behavior of drilling shaft system in copper stave deep hole drilling were analyzed. The effects of the fluctuation of the cutting force, the mass eccentricity and the hydrodynamic f...The stability and nonlinear dynamic behavior of drilling shaft system in copper stave deep hole drilling were analyzed. The effects of the fluctuation of the cutting force, the mass eccentricity and the hydrodynamic forces of cutting fluid could be taken into consideration in the model of drilling shaft system. Based on the isoparametric finite element method, the variational form of Reynolds equation in hydrodynamic fluid was used to calculate nonlinear hydrodynamic forces and their Jacobian matrices simultaneously. In the stability analysis, a new shooting method for rapidly determining the periodic orbit of the nonlinear drilling shaft system and its period was presented by rebuilding the traditional shooting method and changing the time scale. Through the combination of theories with experiment, the correctness and effectiveness of the above methods are verified by using the Floquet theory. The results show that the mass eccentricity can inhibit the whirling motion of drilling shaft to some extent.展开更多
Residual stresses in ion-implanted NiTi alloy are measured by a combined method ofMoir6 interferometry and hole-drilling. Oxygen ions are implanted into the NiTi alloy under a voltage of 30 kV by a dose of 1.0×10...Residual stresses in ion-implanted NiTi alloy are measured by a combined method ofMoir6 interferometry and hole-drilling. Oxygen ions are implanted into the NiTi alloy under a voltage of 30 kV by a dose of 1.0×10^17ions/cm^2 for one hour. Subsequently, in order to avoid dimensional error, a hole is drilled exactly in the center of the sample. The distribution of residual stresses around the hole is measured. It is indicated that the method which combines the Moire interferometry with hole-drilling is able to be used to measure residual stresses produced by ion implantation.展开更多
The object of this work is to investigate the influence of process parameters on drilling characteristics of an Al 1050 sheet with a thickness of 0.2 mm using a pulsed Nd:YAG laser through numerical analyses and exper...The object of this work is to investigate the influence of process parameters on drilling characteristics of an Al 1050 sheet with a thickness of 0.2 mm using a pulsed Nd:YAG laser through numerical analyses and experiments. By comparing the numerical analyses with the experiments, a proper numerical model was obtained. From the results of the numerical analyses and the experiments, the effects of process parameters on entrance diameters of drilled holes, shapes of the holes, taper angles of the holes and temperature distributions in the vicinity of the holes were examined quantitatively. In addition, the optimal drilling condition was estimated to improve the quality of the drilled holes.展开更多
文摘With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various complications.Currently,reagents based on modified natural polymers(which are naturally occurring compounds)and synthetic polymers(SPs)which are polymeric compounds created industrially,are widely used to prevent emerging complications in the drilling process.However,compared to modified natural polymers,SPs form a family of high-molecular-weight compounds that are fully synthesized by undergoing chemical polymerization reactions.SPs provide substantial flexibility in their design.Moreover,their size and chemical composition can be adjusted to provide properties for nearly all the functional objectives of drilling fluids.They can be classified based on chemical ingredients,type of reaction,and their responses to heating.However,some of SPs,due to their structural characteristics,have a high cost,a poor temperature and salt resistance in drilling fluids,and degradation begins when the temperature reaches 130℃.These drawbacks prevent SP use in some medium and deep wells.Thus,this review addresses the historical development,the characteristics,manufacturing methods,classification,and the applications of SPs in drilling fluids.The contributions of SPs as additives to drilling fluids to enhance rheology,filtrate generation,carrying of cuttings,fluid lubricity,and clay/shale stability are explained in detail.The mechanisms,impacts,and advances achieved when SPs are added to drilling fluids are also described.The typical challenges encountered by SPs when deployed in drilling fluids and their advantages and drawbacks are also discussed.Economic issues also impact the applications of SPs in drilling fluids.Consequently,the cost of the most relevant SPs,and the monomers used in their synthesis,are assessed.Environmental impacts of SPs when deployed in drilling fluids,and their manufacturing processes are identified,together with advances in SP-treatment methods aimed at reducing those impacts.Recommendations for required future research addressing SP property and performance gaps are provided.
文摘μEDM(micro-electrical discharge machining)is a process for machining conductive materials without mechanical contact;it is particularly suitable for machining hard materials.The principle consists in creating electrical discharges between a micro-tool and a workpiece,both of which are immersed in a dielectric.It is a complementary process to mechanical,laser,micro-machining techniques,and even to techniques derived from silicon microtechnology(RIE,DRIE,LIGA).However,the resolution ofμEDM is limited;it depends on several electrical and physical parameters.The goal of this paper is to characterize the holes obtained by drilling usingμEDM with different micro-tool diameters(Φ=250μm;Φ=80μm;Φ=40μm;Φ=20μm)for an experimental time of t=2 h.The results obtained let us conclude that a large diameter micro-tool(Φ=250μm)leads to removing a larger amount of material(43×10^(5)μm^(3))than small diameters:Φ=80μm;Φ=40μm;Φ=20μm where the removed volume is equal to 2.6×10^(5)μm^(3);105μm^(3);0.4×10^(5)μm^(3),respectively.The electrode-tool diameter influences the maximum depth of the holes;a diameter ofΦ=250μm generates a hole where the maximum depth is 170μm while small diameters:Φ=80μm;Φ=40μm;Φ=20μm provide holes with a depth of 82μm;51μm;50μm respectively.Through these experiments,we can also conclude that the lateral gap of the holes is almost constant.It is about 40μm whatever the diameter.
基金Projects(51278166,51478163)supported by the National Natural Science Foundation of ChinaProject(2015B17414)supported by the Fundamental Research Funds for the Central Universities,China
文摘Force analysis using a compact tension model, as recommended by ASTM, was carried out on a crack stop hole. The stress before, and after, drilling the hole was compared in terms of stress concentration and stress gradient. The optimum drilling location and diameter were studied through analysis of different locations and diameters. By analyzing the effects of flank holes and an additional hole, drilling advice was proposed and fatigue testing of the cracks in a steel bridge deck with a crack stop hole was conducted. The results show that the stress at the crack tip with a crack stop hole decreased, and the major principal stress around the hole was distributed accordingly. The optimum position of the crack stop hole centre was where the centre of the crack stop hole was situated behind the crack and the hole edge coincided with the crack tip. Therefore, hole diameters larger than 8 mm, or those weakening the section by 10%, were suggested as the best diameters. In terms of multi-hole crack stopping, a flank hole was not recommended. The optimum horizontal position of flank holes was at a distance of 1/4 of a single hole diameter from, and in front of, the single hole. Besides, the experiment showed that crack stop hole could only prevent cracks from growing and had no influence on crack growth rate.
基金Supported by the Major Science and Technology Project(2012ZX04003-031)
文摘Revolution radius is one of the significant parameters in orbital drilling,which has great influence on many factors,such as the cutting area of front and side cutting edge,undeformed chip geometry,delamination and burr at hole exit side,hole surface roughness,cutting tool force and deflection,chip removal and heat transmission.First,the influence of revolution radius on the factors is discussed theoretically in detail.Analysis results show that big revolution radius can reduce axial cutting force,restrain exit delamination and burr,and improve chip removal and heat transmission.Then,single factor test and orthogonal test are utilized in the two processing methods as machining unidiameter holes with several cutting tools and machining different diameter holes with one tool.Finally,the influence of revolution radius on cutting force and hole machining precision is studied.These results provide a profound foundation for future optimization of cutting control parameters.
文摘The ages of coral reef samples from several shallow drill holes in the South China Sea are determined by ESR and U-series (230Th/234U) methods. The experimental results show ideal agreement between ESR and U-series ages and that the coral reefs were formed in the early Holocene. In the determination of natural total dose of coral reef by use of the additive dose method good results can be obtained by exponential fitting, no matter how the effect of dose saturation is. It was found that the ratio of the natural ESR signal intensity ( I0) to the ESR signal intensity at dose saturation ( Imax) of sample can reflect the significance of a irradiation efficiency-k value. Using the k value of sample determined by the formula given in this paper, the precision of ESR dating of marine carbonates can be improved.
基金supported by the research Grant within the framework of the Federal Target Program ‘Scientific and Academic Staff of Innovative Russia’ during the years of 2009–2013competitive activity 1.3.1. ‘Research conducted by young researchers, Ph.D. holders’, the project theme ‘Research of power pulse interaction in a drilling tool and in rock mass in underground borehole drilling’
文摘A possibility of the efficient use of rotary percussive drilling to provide drilling smaller diameter holes(40–70 mm) both in mining and prospecting is disclosed herein. A new construction designed for the nipple thread connection is described. The relative amplitude variation, change of power pulse time and energy in their propagation throughout the drilling tool are determined. A possibility of the efficient power pulse transfer along the drill string to the rock destruction tools with new nipple connections which allow automating the make-up and breakout system of drill pipe was supported by experiments.
文摘With special drilling operation equipment and specific conditions of geology, how does drilling fluid carry cuttings effectively? So far, it is still an urgent problem for drilling researchers to study. This work just aims at the actual engineering background to develop studying model. In this paper, according to non Newtonian fluid mechanics, the law of the solid liquid, two phase fluid flow and actual drilling engineering, the major factors affecting cuttings transport are drilling fluid velocity, hole inclination and fluid rheological properties. Getting a clear understanding of the law of drilling fluid and its cutting taking mechanism, this paper puts forward a model for analysis of field data and quantitative forecast of cutting taking capability of drilling fluid. The full scale annular test section was 6.1 m with 76 and 114 mm drillpipe in a 203 mm ID (wellbore diameter). Hole angle varied from 0° to 90°.
基金supported by the Science and Technology Programme of Shijiazhuang under Grant 151130081A
文摘Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss produced by multi-beam parabolic antenna.Based on 3-D printing technique,Luneburg lens antennas by drilling holes are studied.Permittivity and loss tangent of the equivalent lens materials can be influenced by original materials,hole shapes,hole directions,and porosity.After tests,polystyrene with waxes may be the most appropriate materials for Luneburg lens with high strength.Permittivity with the shape of triangle is the lowest due to the homogeneity.Relative permittivities with the direction at a range of 15°-45°are lower while loss tangent at a range of 0°-30°.Radial directional holes are more appropriate for Luneburg lens.The relative permittivity is decreased with the increment of porosity.After calculations,the forecasts calculated by Looyenga and A-BG theory are more precise.Finally,Luneburg lens with two layers is fabricated by 3-D printing.
文摘Manufacturing accuracy, especially position accuracy of fastener holes, directly affects service life and security of aircraft. The traditional modification has poor robustness, while the modification based on laser tracker costs too much. To improve the relative position accuracy of aircraft assembly drilling, and ensure the hole-edge distance requirement, a method was presented to modify the coordinates of drilling holes. Based on online inspecting two positions of pre-assembly holes and their theoretical coordinates, the spatial coordinate transformation matrix of modification could be calculated. Thus the straight drilling holes could be modified. The method improves relative position accuracy of drilling on simple structure effectively. And it reduces the requirement of absolute position accuracy and the cost of position modification. And the process technician also can use this method to decide the position accuracy of different pre-assembly holes based on the accuracy requirement of assembly holes.
文摘With the innovation and development of offshore oil drilling technology, drilling wells in deep waters areas have become an important activity for the development of new hydrocarbon reservoirs in this type of environment. CNOOC (China National Offshore Oil Corporation) won the rights to exploit two unexplored deepwater blocks in the Gulf of Mexico, in a bid realized by the Mexican Government (CNH), in 2016. The challenge to combine the newest technology with the oil industry experienced knowledge to lead the exploration and development of these deep-water blocks in Mexico is around the corner. Therefore, the basic techniques for deep waters wells drilling and the main potential risks are expounded in this paper. A set of deep waters wells drilling processes and methodologies are previously designed, and a specific case is demonstrated next, which provides a referential model for deep waters wells drilling in the Gulf of Mexico.
基金This project was granted bythe National Developmentand Reform Commission.Item Number:20041138
文摘Based on the content of radioactive elements (U, Th, K) of strata in two drill holes in the Fuzhou basin, and combined with the result of spore_pollen analysis, the relationship between radioactivity and lithology and deposit environments is discussed and the results show that the content of radioactive substances is related to the granularity and lithology in sediment, and it is higher in argillaceous sediment (e.g. silt and clay), lower in sand sediment and in the middle in gravels between the above two kinds of sediment. The content of radioactive substances is also related to paleoclimate. A warm and humid environment is propitious to the deposition of radioactive substances, while a cool and dry climate is just the reverse.
文摘Enhancement of technology and techniques for drilling deep directed oil and gas bore hole is one of the most important problems of the current petroleum industry.Not infrequently, the drilling of these bore holes is attended by occurrence of extraordinary situations associated with technical accidents. Among these is the Eulerian loss of stability of a drill string in the channel of a curvilinear bore hole. Methods of computer simulation should play a dominant role in prediction of these states. In this paper, a new statement of the problem of critical buckling of the drill strings in 3D curvilinear bore holes is proposed. It is based on combined use of the theory of curvilinear elastic rods, Eulerian theory of stability, theory of channel surfaces, and methods of classical mechanics of systems with nonlinear constraints. It is noted that the stated problem is singularly perturbed and its solutions have the shapes of localized harmonic wavelets. The calculation results showed that the friction effects lead to essential redistribution of internal axial forces, as well as changing the eigenmode shapes and sites of their localization. These features make the buckling phenomena less predictable and raise the role of computer simulation of these effects.
基金This study was supported by the Ministry of Land and Resources of China Projects“1:250000 Regional Geological Surveyofthe Lianyugang Sheet (150C002004) of P.R.China""Geological Research for Selecting a Drillhole in the Donghai TargetArea of the Chinese Continental Scientific Drilling Programme”.
文摘Study of micro-area chemical compositions indicates that phengite in albite gneiss from hole ZK2304 of the Donghai region has evident compositional zoning. SiO2 and tetrahedrally coordinated Si contents decrease, and Al2O3, AlIVand AlVIcontents increase gradually from core to rim. However, K2O, MgO and FeO contents basically remain unchanged from core to rim. According to P-T estimates obtained from geothermometers and barometers, combined with previous experimental data, the core belt (micro-area I) of phengite was formed at T=637–672°C and P=1.55–1.73 GPa, and the transitional belt (micro-area II) of the phengite were formed at T=594–654°C and P=1.35–1.45 GPa. Towards the rim belt (micro-area III), the temperature decreased slightly, but the pressure decreased rapidly with T=542–630°C and P=1.12–1.19 GPa. The P-T evolution path recorded by the compositional zoning of phengite is characterized by significant near-isothermal decompression, revealing that the gneiss has undergone high-pressure-ultrahigh-pressure metamorphism. The compositional zoning of the phengite in the albite gneiss may have formed in the geodynamic process of rapid exhumation in the Sulu ultrahigh-pressure metamorphic belt.
文摘Foam drilling is increasingly used to develop low pressure reservoirs or highly depleted mature reservoirs because of minimizing the formation damage and potential hazardous drilling problems. Prediction of the cuttings concentration in the wellbore annulus as a function of operational drilling parameters such as wellbore geometry, pumping rate, drilling fluid rheology and density and maximum drilling rate is very important for optimizing these parameters. This paper describes a simple and more reliable artificial neural network (ANN) method and multiple linear regression (MLR) to predict cuttings concentration during foam drilling operation. This model is applicable for various borehole conditions using some critical parameters associated with foam velocity, foam quality, hole geometry, subsurface condition (pressure and temperature) and pipe rotation. The average absolute percent relative error (AAPE) between the experimental cuttings concentration and ANN model is less than 6%, and using MLR, AAPE is less than 9%. A comparison of the ANN and mechanistic model was done. The AAPE values for all datasets in this study were 3.2%, 8.5% and 10.3% for ANN model, MLR model and mechanistic model respectively. The results show high ability of ANN in prediction with respect to statistical methods.
基金financially supported by the National Natural Science Foundation of China(Grant Numbers:51804322,51821092,51774301,U1762214)National Key Research and Development Project(Grant Numbers:2017ZX05009003,2017ZX05005-005-007,2016YFC0303303)other projects(Grant Numbers:2462017YJRC050,SXCU-201903,CNOOC-KJ135ZDXM37SZ05SZ)。
文摘Efficient cuttings transport and improving rate of penetration(ROP)are two major challenges in horizontal drilling and extended reach drilling.A type of jet mill bit(JMB)may provide an opportunity to catch the two birds with one stone:not only enhancing cuttings transport efficiency but also improving ROP by depressuring at the bottom hole.In this paper,the JMB is further improved and a new type of depressure-dominated JMB is presented;meanwhile,the depressurization capacity of the depressure-dominated JMB is investigated by numerical simulation and experiment.The numerical study shows that low flow-rate ratio helps to enhance the depressurization capacity of the depressure-dominated JMB;for both depressurization and bottom hole cleaning concern,the flow-rate ratio is suggested to be set at approximately 1:1.With all other parameter values being constant,lower dimensionless nozzle-to-throat-area ratio may result in higher depressurization capacity and better bottom hole cleaning,and the optimal dimensionless nozzle-to-throat-area ratio is at approximately0.15.Experiments also indicate that reducing the dimensionless flow-rate ratio may help to increase the depressurization capacity of the depressure-dominated JMB.This work provides drilling engineers with a promising tool to improve ROP.
基金the National Natural Science Foundation of China (10772117, 10572089)
文摘The hole-drilling method is one of the most wellknown methods for measuring residual stresses. To identify unknown plane stresses in a specimen, a circular hole is first drilled in the infinite plate under plane stress, then the strains resulting from the hole drilling is measured. The strains may be acquired from interpreting the Moire signature around the hole. In crossed grating Moire interferometry, the horizontal and vertical displacement fields (u and v) can be obtained to determinate two strain fields and one shearing strain field. In this paper, by means of Moire interferometry and three directions grating (grating rosette) developed by the authors, three displacement fields (u, v and s) are obtained to acquire three strain fields. As a practical application, the hole-drilling method is adopted to measure the relief strains for aluminum and fiber reinforced composite. It is a step by step method; in each step a single laminate or equivalent depth is drilled to find some relationships between the drilling depth and the residual strains relieved in the fiber reinforced composite materials.
基金Project(2007CB707706) supported by the Major State Basic Research Development Program of ChinaProjects(2007E213,2007E203) supported by the Natural Science Foundation of Shaanxi Province,China
文摘The stability and nonlinear dynamic behavior of drilling shaft system in copper stave deep hole drilling were analyzed. The effects of the fluctuation of the cutting force, the mass eccentricity and the hydrodynamic forces of cutting fluid could be taken into consideration in the model of drilling shaft system. Based on the isoparametric finite element method, the variational form of Reynolds equation in hydrodynamic fluid was used to calculate nonlinear hydrodynamic forces and their Jacobian matrices simultaneously. In the stability analysis, a new shooting method for rapidly determining the periodic orbit of the nonlinear drilling shaft system and its period was presented by rebuilding the traditional shooting method and changing the time scale. Through the combination of theories with experiment, the correctness and effectiveness of the above methods are verified by using the Floquet theory. The results show that the mass eccentricity can inhibit the whirling motion of drilling shaft to some extent.
基金National Natural Science Foundation of China (10572155)
文摘Residual stresses in ion-implanted NiTi alloy are measured by a combined method ofMoir6 interferometry and hole-drilling. Oxygen ions are implanted into the NiTi alloy under a voltage of 30 kV by a dose of 1.0×10^17ions/cm^2 for one hour. Subsequently, in order to avoid dimensional error, a hole is drilled exactly in the center of the sample. The distribution of residual stresses around the hole is measured. It is indicated that the method which combines the Moire interferometry with hole-drilling is able to be used to measure residual stresses produced by ion implantation.
基金supported by a grant-in-aid of Regional Innovation Center(RIC),New Technology Development and Research Center of Laser Application in Chosun University,Korea.
文摘The object of this work is to investigate the influence of process parameters on drilling characteristics of an Al 1050 sheet with a thickness of 0.2 mm using a pulsed Nd:YAG laser through numerical analyses and experiments. By comparing the numerical analyses with the experiments, a proper numerical model was obtained. From the results of the numerical analyses and the experiments, the effects of process parameters on entrance diameters of drilled holes, shapes of the holes, taper angles of the holes and temperature distributions in the vicinity of the holes were examined quantitatively. In addition, the optimal drilling condition was estimated to improve the quality of the drilled holes.