Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal ...Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal of backward jets in bottom holes. Meanwhile this paper establishes a mechanical equation for a high pressure hose and analyzes the axial force distribution. Laboratory experiments indicate that the flow rate, the angle between the backward nozzle axis and the jet bit axis, and the hole diameter are the major influencing factors; the generation of the pulling force is mainly due to the inlet pressure of the jet bit; the backward jets can significantly increase not only the pulling force but also the stability of jet bits. The pulling force would reach 8,376 N under experimental conditions, which can steadily pull the high-pressure hose forward.展开更多
42CrMo steel has the characteristics of high strength,high wear resistance,high impact resistance,and fatigue resistance.Therefore,drilling 42CrMo steel has always been a challenging task.The indexable drill bit has t...42CrMo steel has the characteristics of high strength,high wear resistance,high impact resistance,and fatigue resistance.Therefore,drilling 42CrMo steel has always been a challenging task.The indexable drill bit has the advantages of high processing efficiency and low processing cost and has been widely used in the field of aerospace hole processing.To better understand the machining mechanism of the indexable drill bit,this paper uses the Coupled EulerianLagrangian method(CEL)to simulate the three-dimensional drilling model for the first time.The simulation results of the drilling force obtained by the CEL method and Lagrangian method are compared with the experimental results.It is verified that the CEL method is easy to converge and can avoid the problem of program interruption caused by mesh distortion,and the CEL simulation value is more consistent with the actual value.Secondly,the simulation results of cutting force and blade cutting edge node temperature under different process parameters are extracted.The variation of time domain cutting force,frequency domain cutting force and tool temperature with process parameters are obtained.This study provides a new method for the prediction of cutting performance and the optimization of process parameters of indexable drills.展开更多
The deviation control of directional drilling is essentially the controlling of two angles of the wellbore actually drilled, namely, the inclination and azimuth. In directional drilling the bit trajectory never coinci...The deviation control of directional drilling is essentially the controlling of two angles of the wellbore actually drilled, namely, the inclination and azimuth. In directional drilling the bit trajectory never coincides exactly with the planned path, which is usually a plane curve with straight, building, holding, and dropping sections in succession. The drilling direction is of course dependant on the direction of the resultant forces acting on the bit and it is quite a tough job to hit the optimum target at the hole bottom as required. The traditional passive methods for correcting the drilling path have not met the demand to improve the techniques of deviation control. A method for combining wellbore surveys to obtain a composite, more accurate well position relies on accepting the position of the well from the most accurate survey instrument used in a given section of the wellbore. The error in each position measurement is the sum of many independent root sources of error effects. The relationship between surveys and other influential factors is considered, along with an analysis of different points of view. The collaborative work describes, establishes a common starting point of wellbore position uncertainty model, definition of what constitutes an error model, mathematics of position uncertainty calculation and an error model for basic directional service.展开更多
Over the last 10 years,the China Geological Survey has deployed 137 slim-hole shale gas geological exploration wells for coring entire wellbores.These wells are primarily located in new blocks and geological formation...Over the last 10 years,the China Geological Survey has deployed 137 slim-hole shale gas geological exploration wells for coring entire wellbores.These wells are primarily located in new blocks and geological formations where neighboring well data are insufficient,beyond the scope of developed oil fields in China,or outside of oil and gas company mining-right areas.The drilling rig equipment,coring tools,and core drill bits of slim-hole shale gas drilling technology are different from those associated with traditional petroleum drilling.Many studies have been conducted on non-coring slim-hole drilling technology.This paper focuses on coring technology and drilling safety,summarizing a set of high-efficiency shale gas drilling equipment and technology systems based on geological drilling equipment and techniques(that can be used for solid mineral exploration).We report on:1)an improved vertical shaft drilling rig adapted to shale gas well control safety;2)high-efficiency core drilling techniques,focusing on coring tools,and techniques incorporating an inverted tower drilling tool combination,air circulation follow-through technology,and expanded casing technology;3)research progress on high-efficiency core drill bits,including non-planar tooth polycrystalline diamond compact bits and impregnated diamond core bits,along with their application effects.This research provides substantial advances in drill-core technology and improvements in exploration efficiency.Moreover,it provides a reference frame for well structural design and selection of construction technology for shale gas exploration drilling projects.展开更多
Chemical vapor deposition (CVD) diamond coated drills are fabricated by depositing diamond films on Co-cemented tungsten carbide (WC-Co) drills. The characteristics of as-deposited diamond coatings are investigated by...Chemical vapor deposition (CVD) diamond coated drills are fabricated by depositing diamond films on Co-cemented tungsten carbide (WC-Co) drills. The characteristics of as-deposited diamond coatings are investigated by scanning electron microscope (SEM) and Raman spectra. To evaluate the cutting performance of diamond coated drills, comparative drilling tests are conducted using diamond coated and uncoated WC-Co drills, with carbon fiber reinforced plastics (CFRPs) as the workpiece on a high-speed computer numerical control (CNC) machine. Thrust force and tool wear are measured during the drilling process. The results show that diamond coated drill exhibits better cutting performance, compared with the uncoated drill. The value of flank wear is about 70 μm after machining 90 holes, about a half of that of the WC-Co drill with 145 μm after drilling only 30 holes. The wear rate of WC-Co drill is higher than that of diamond coated drill before diamond films peeling off. The diamond coated drill achieves more predictable hole quality. The improved cutting performance of the diamond coated drill is due to the high hardness, wear resistance and low coefficient of friction.展开更多
基金supported by High-tech Research and Development Program of China (No. 2007AA09Z315)Doctoral Foundation of Ministry of Education of China (No. 20070425006)
文摘Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal of backward jets in bottom holes. Meanwhile this paper establishes a mechanical equation for a high pressure hose and analyzes the axial force distribution. Laboratory experiments indicate that the flow rate, the angle between the backward nozzle axis and the jet bit axis, and the hole diameter are the major influencing factors; the generation of the pulling force is mainly due to the inlet pressure of the jet bit; the backward jets can significantly increase not only the pulling force but also the stability of jet bits. The pulling force would reach 8,376 N under experimental conditions, which can steadily pull the high-pressure hose forward.
基金supported by the Natural Science Foundation of Heilongjiang Province(No.TD2022E003)the National Natural Science Foundation of China(No.52175393)。
文摘42CrMo steel has the characteristics of high strength,high wear resistance,high impact resistance,and fatigue resistance.Therefore,drilling 42CrMo steel has always been a challenging task.The indexable drill bit has the advantages of high processing efficiency and low processing cost and has been widely used in the field of aerospace hole processing.To better understand the machining mechanism of the indexable drill bit,this paper uses the Coupled EulerianLagrangian method(CEL)to simulate the three-dimensional drilling model for the first time.The simulation results of the drilling force obtained by the CEL method and Lagrangian method are compared with the experimental results.It is verified that the CEL method is easy to converge and can avoid the problem of program interruption caused by mesh distortion,and the CEL simulation value is more consistent with the actual value.Secondly,the simulation results of cutting force and blade cutting edge node temperature under different process parameters are extracted.The variation of time domain cutting force,frequency domain cutting force and tool temperature with process parameters are obtained.This study provides a new method for the prediction of cutting performance and the optimization of process parameters of indexable drills.
文摘The deviation control of directional drilling is essentially the controlling of two angles of the wellbore actually drilled, namely, the inclination and azimuth. In directional drilling the bit trajectory never coincides exactly with the planned path, which is usually a plane curve with straight, building, holding, and dropping sections in succession. The drilling direction is of course dependant on the direction of the resultant forces acting on the bit and it is quite a tough job to hit the optimum target at the hole bottom as required. The traditional passive methods for correcting the drilling path have not met the demand to improve the techniques of deviation control. A method for combining wellbore surveys to obtain a composite, more accurate well position relies on accepting the position of the well from the most accurate survey instrument used in a given section of the wellbore. The error in each position measurement is the sum of many independent root sources of error effects. The relationship between surveys and other influential factors is considered, along with an analysis of different points of view. The collaborative work describes, establishes a common starting point of wellbore position uncertainty model, definition of what constitutes an error model, mathematics of position uncertainty calculation and an error model for basic directional service.
基金supported by project of China Geological Survey (Grant No.DD20230262,DD20221653,DD20221674,DD20190725,and DD20190561)the Science and Technology Innovation Fund of the Oil and Gas Survey (Grant No.[2023]-YC03).
文摘Over the last 10 years,the China Geological Survey has deployed 137 slim-hole shale gas geological exploration wells for coring entire wellbores.These wells are primarily located in new blocks and geological formations where neighboring well data are insufficient,beyond the scope of developed oil fields in China,or outside of oil and gas company mining-right areas.The drilling rig equipment,coring tools,and core drill bits of slim-hole shale gas drilling technology are different from those associated with traditional petroleum drilling.Many studies have been conducted on non-coring slim-hole drilling technology.This paper focuses on coring technology and drilling safety,summarizing a set of high-efficiency shale gas drilling equipment and technology systems based on geological drilling equipment and techniques(that can be used for solid mineral exploration).We report on:1)an improved vertical shaft drilling rig adapted to shale gas well control safety;2)high-efficiency core drilling techniques,focusing on coring tools,and techniques incorporating an inverted tower drilling tool combination,air circulation follow-through technology,and expanded casing technology;3)research progress on high-efficiency core drill bits,including non-planar tooth polycrystalline diamond compact bits and impregnated diamond core bits,along with their application effects.This research provides substantial advances in drill-core technology and improvements in exploration efficiency.Moreover,it provides a reference frame for well structural design and selection of construction technology for shale gas exploration drilling projects.
基金the National Natural Science Foundation of China(Nos.51275302 and 51005154)the Important National Science and Technology Specific Projects(No.2012ZX04003-031)
文摘Chemical vapor deposition (CVD) diamond coated drills are fabricated by depositing diamond films on Co-cemented tungsten carbide (WC-Co) drills. The characteristics of as-deposited diamond coatings are investigated by scanning electron microscope (SEM) and Raman spectra. To evaluate the cutting performance of diamond coated drills, comparative drilling tests are conducted using diamond coated and uncoated WC-Co drills, with carbon fiber reinforced plastics (CFRPs) as the workpiece on a high-speed computer numerical control (CNC) machine. Thrust force and tool wear are measured during the drilling process. The results show that diamond coated drill exhibits better cutting performance, compared with the uncoated drill. The value of flank wear is about 70 μm after machining 90 holes, about a half of that of the WC-Co drill with 145 μm after drilling only 30 holes. The wear rate of WC-Co drill is higher than that of diamond coated drill before diamond films peeling off. The diamond coated drill achieves more predictable hole quality. The improved cutting performance of the diamond coated drill is due to the high hardness, wear resistance and low coefficient of friction.
