Influence of identical applied initial pressures on the radial surfaces of a hollow cylinder which is compose of materials with first power hypo-elastic constitutive model was investigated.The basic equations of the p...Influence of identical applied initial pressures on the radial surfaces of a hollow cylinder which is compose of materials with first power hypo-elastic constitutive model was investigated.The basic equations of the problem were built up based on the framework of piecewise homogeneous body model with the use of three-dimensional linearized theory of elastic waves in initially stressed bodies(TLTEWISB).With the method proposed previously,this problem was then solved numerically.Moreover,the dispersion group velocity of the lowest order mode with different initial pressures was also studied.It can be concluded that the initial pressure and the geometry parameters will induce considerable changes of different degrees in dispersive relation between phase velocity and wave number in opposite trend(positive in initial pressure and negative in thickness).展开更多
There are few report on the directly measurement of the initial shock pressure of explosive charge at its interface of water for underwater explosion. The special technologies have been taken to the measurement system...There are few report on the directly measurement of the initial shock pressure of explosive charge at its interface of water for underwater explosion. The special technologies have been taken to the measurement system with manganin piezoresistive gauge （PRG） in order to measure the initial shock pressure at the interface and its near field of TNT chare and water. The free-holding PRG film gauge can directly determine the shock peak pressure at the interface and near field of TNT charge up to 12.85 GPa, which is satisfying for the good agreement to the 12.97 GPa with one dimensional theoretical analysis and 12.86 GPa with numerical simulation. The maximum discrepancy is 0.93 %. The results show that it is precise and reliable to determine the initial shock pressure of underwater explosion charge with the PRG technology.展开更多
The mechanism of the shift of the band-gap in phononic crystal （PC） with different initial confining pressures is studied experimentally and numerically. The experimental results and numerical analysis simultaneousl...The mechanism of the shift of the band-gap in phononic crystal （PC） with different initial confining pressures is studied experimentally and numerically. The experimental results and numerical analysis simultaneously indicate that the confining pressure can efficiently tune the location in and the width of the band-gap. The present work provides a basis for tuning the band-gap of phononic crystal in engineering applications.展开更多
Although a large volume of mudcake filtration test data is available in the literature, effects of mudcake on wellbore strengthening cannot be quantified without incorporating the data into a stress-analysis model. Tr...Although a large volume of mudcake filtration test data is available in the literature, effects of mudcake on wellbore strengthening cannot be quantified without incorporating the data into a stress-analysis model. Traditional models for determining fracture initiation pressure （FIP） either consider a wellbore with an impermeable mudcake or with no mudcake at all. An analytical model considering permeable mudcake is proposed in this paper. The model can predict pore pressure and stress profiles around the wellbore, and consequently the FIP, for different mudcake thickness, permeability, and strength. Numerical examples are provided to illustrate the effects of these mudcake parameters. The results show that a low-permeability mudcake enhances FIP, mainly through restricting fluid seepage and pore pressure increase in the near- wellbore region, rather than by mudcake strength. Fluid loss pressure （FLP） should be distinguished from FIP when a mudcake is present on the wellbore wall. Fracture may occur behind the mudcake at FIP without mudcake rupture. The small effect of mudcake strength on FIP does not mean its effect on FLP is small too. Mudcake strength may play an important role in maintaining integrity of the wellbore once a fracture has initiated behind the mudcake.展开更多
To reveal the water inrush mechanics of underground deep rock mass subjected to dynamic disturbance such as blasting, compression-shear rock crack initiation rule and the evolution of crack tip stress intensity factor...To reveal the water inrush mechanics of underground deep rock mass subjected to dynamic disturbance such as blasting, compression-shear rock crack initiation rule and the evolution of crack tip stress intensity factor are analyzed under static-dynamic loading and seepage water pressure on the basis of theoretical deduction and experimental research. It is shown that the major influence factors of the crack tip stress intensity factor are seepage pressure, dynamic load, static stress and crack angle. The existence of seepage water pressure aggravates propagation of branch cracks. With the seepage pressure increasing, the branch crack experiences unstable extension from stable propagation. The dynamic load in the direction of maximum main stress increases type I crack tip stress intensity factor and its influence on type II crack intensity factor is related with crack angle and material property. Crack initiation angle changes with the dynamic load. The initial crack initiation angle of type I dynamic crack fracture is 70.5°. The compression-shear crack initial strength is related to seepage pressure, confining pressure, and dynamic load. Experimental results verify that the initial crack strength increases with the confining pressure increasing, and decreases with the seepage pressure increasing.展开更多
An analytical model of a ring with six yield hinges and two deformable arc segments is presented for. the prediction of the buckle propagation pressure and initiation pressure in offshore pipelines. The configuration ...An analytical model of a ring with six yield hinges and two deformable arc segments is presented for. the prediction of the buckle propagation pressure and initiation pressure in offshore pipelines. The configuration of a fully collapsed ring is considered as a real dumbbell shape with a line touch between two 'bells', instead of the dumbbell shape with a point touch of two diametrically opposite points. Calculations are performed assuming that the dominant effect on the plastic energy dissipation has the circumferential bending mode. For the linear strain-hardening materials it is found that theoretical predictions based on the above model for both propagation pressure and initiation nressure are in good agreement with experimental results of Kyriakides et al.展开更多
In order to protect C/C composites from oxidation, SiC-MoSi2 composite coating was synthesized by chemical vapor infiltration /reaction （CVI/CVR） technology. A porous Mo layer was prefabricated on SiC coated C/C com...In order to protect C/C composites from oxidation, SiC-MoSi2 composite coating was synthesized by chemical vapor infiltration /reaction （CVI/CVR） technology. A porous Mo layer was prefabricated on SiC coated C/C composites, and then MoSi2 and SiC were subsequently prepared in a CVI /CVR process using methyltrichlorosilane （MTS） as precursor. The deposition and reaction mechanism of the MoSi2-SiC composite coating was investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The oxidation behavior of SiC-MoSi2 coated specimens was tested. The results show that the porous Mo layer can be densified with SiC phase decomposed from MTS, and transformed into SiC-MoSi2 by reacting with MTS as well. A dense composite coating was prepared with optimized deposition parameters. The coated specimen exhibits a good oxidation resistance with a little mass loss of 1.25% after oxidation at 1500 °C for 80 h.展开更多
In this paper the behavior of an O-ring made of NBR rubber was investigated under extreme conditions. The effect of the extreme initial compression, operating pressure and extreme temperature conditions were examined....In this paper the behavior of an O-ring made of NBR rubber was investigated under extreme conditions. The effect of the extreme initial compression, operating pressure and extreme temperature conditions were examined. The rubber material was tested in simple tension, pure shear and equibiaxial tension modes complemented with a Dynamic Mechanical Thermal Analysis (DMTA) to capture the viscoelastic behavior of the material. For the investigation, a large-strain viscoelastic material model was developed by the authors, to take into account the large deformations caused by extreme conditions. Insufficient space during installation causes extreme initial compression consequently leading the material to crack on the contacting outer surfaces. It was found that the excessive strain and friction induced shear stress contributes primarily to this phenomenon. Extreme operating pressure causes the seal to penetrate into the gap between the shaft and the housing. This behavior damages the material and cracks appear on the seal. High strain areas were found in the proximity of the gap in the material. The analysis of the extreme operating temperature showed that during cooling the O-ring can completely loose its ability to seal at -70°C. There are three contributing factors: the speed of cooling, the temperature and the coefficient of thermal expansion.展开更多
In this paper, detonation parameters of fuel cloud, such as propylene oxide （PO）, isopropyl nitrate （IPN）, hex- ane, 90# oil and decane were measured in a self-designed and constructed vertical shock tube. Results...In this paper, detonation parameters of fuel cloud, such as propylene oxide （PO）, isopropyl nitrate （IPN）, hex- ane, 90# oil and decane were measured in a self-designed and constructed vertical shock tube. Results show that the deto- nation pressure and velocity of PO increase to a peak value and then decrease smoothly with increasing equivalence ra- tio. Several nitrate sensitizers were added into PO to make fuel mixtures, and test results indicated that the additives can efficiently enhance detonation velocity and pressure of fuel cloud and one type of additive n-propyl nitrate （NPN） played the best in the improvement. The critical initiation energy that directly initiated detonation of all the test liquid fuel clouds showed a U-shape curve relationship with equiva- lence ratios. The optimum concentration lies on the rich-fuel side （;b 〉 1）. The critical initiation energy is closely related to molecular structure and volatility of fuels. IPN and PO have similar critical values while that of alkanes are larger. Detonation cell sizes of PO were respectively investigated at 25;C, 35;C and 50;C with smoked foil technique. The cell width shows a U-shape curve relationship with equivalence ratios at all temperatures. The minimal cell width also lies on the rich-fuel side （;b 〉 1）. The cell width of PO vapor is slightly larger than that of PO cloud. Therefore, the deto- nation reaction of PO at normal temperature is controlled by gas phase reaction.展开更多
For figuring out the stress interference of multiphase fracture combinations and its effect on the fracture initiation pressure of subsequent hydraulic fracturing,a calculation model for the coupled stress field with ...For figuring out the stress interference of multiphase fracture combinations and its effect on the fracture initiation pressure of subsequent hydraulic fracturing,a calculation model for the coupled stress field with multiple induced fractures preexisted was established based on the calculation model for the stress field with single induced fracture preexisted,and the change laws of circumferential stress field around the wellbore under the effect of induced stress were analyzed.Then,the fracture initiation pressure of subsequent hydraulic fracturing was calculated according to the fracturing mechanics criterion.Finally,the effects of the length,phase,horizontal principal stress difference co-efficient and quantity of preexisting fractures on its initiation pressure were analyzed.And the following research results were obtained.First,the circumferential stress difference in the area near the fractures behind the preexisting fractures increase greatly and even the horizontal principal stress is reversed.Second,as the length of new preexisting fractures increases,the initiation pressure of initial preexisting fractures rises first and then drops.And when the length of new preexisting fractures is equal to that of the initial preexisting fractures,the initiation pressure of initial preexisting fractures drops quickly first and then slowly.Third,the initiation pressure of high phase fractures is lower than that of low phase fractures.Fourth,with the increase of fracture quantity,the initiation pressure of new preexisting fractures drops gradually,but the decline trend of initiation pressure difference is not obvious.Fifth,the stress interference of multiphase fractures influences the fracture initiation pressure,and high-phase long fractures and low-phase short fractures are both favorable for the simultaneous initiation of multiphase fractures.Sixth,syn-chronous propagation of multiple fractures can generate more complicated stress interference and excite the evolution of hydraulic fracture network,so as to realize uniform fracturing stimulation.In conclusion,the research results can provide a theoretical guidance for the design of fracturing operation,e.g.perforation phase of blasting induced fracturing,scale of induced fractures,and pump pressure of subsequent hydraulic fracturing.展开更多
Low average single-well production resulting in low economic benefit has become the main bottleneck of the CBM gas development in China.So it is significant to choose suitable efficient development technologies based ...Low average single-well production resulting in low economic benefit has become the main bottleneck of the CBM gas development in China.So it is significant to choose suitable efficient development technologies based on CBM geological factors for high rank CBM recovery enhancement.In view of this,CBM geological factors were analyzed,different geological models were established and the corresponding models of development engineering technologies were thus put forward.It was proposed that the four main factors affecting high rank CBM recovery from a lower degree to a higher degree respectively include coal texture,rank of coal metamorphism,in-situ stress,and the ratio of critical desorption pressure to initial reservoir pressure.On this basis,four engineering geological models were classified as follows:vertical well,open-hole multilateral horizontal well,U-shaped and roof tree-like horizontal wells,and fish-bone and L-shaped wells.It is concluded that the former two models are more adaptable in such areas with better coal texture and high degree of thermal maturity,while the latter two are commonly applied in a wide range of areas.展开更多
Horizontal wells show better affect and higher success rate in low water ratio cement,complex fracture zone,crevice and heavy oil blocks,it is the main measures to expand control area of a single well.Hydraulic fractu...Horizontal wells show better affect and higher success rate in low water ratio cement,complex fracture zone,crevice and heavy oil blocks,it is the main measures to expand control area of a single well.Hydraulic fracturing technology is the most financial way to improve the penetration of the reservoir to increase the production.However,compare with the vertical wells,the fracture of Horizontal wells are more complex,and lead to the initiation crack pressure is much higher than vertical wells.In this paper,defined the crack judging basis,and established the finite element model which could compute the initial crack pressure,to research the affection mechanism of perforation azimuth angle,density,diameter and depth,to provide references of perforation project's design and optimize.The research of this paper has significances on further understanding the affection mechanism of perforation parameters.展开更多
基金Project(51378463)supported by National Natural Science Foundation of China
文摘Influence of identical applied initial pressures on the radial surfaces of a hollow cylinder which is compose of materials with first power hypo-elastic constitutive model was investigated.The basic equations of the problem were built up based on the framework of piecewise homogeneous body model with the use of three-dimensional linearized theory of elastic waves in initially stressed bodies(TLTEWISB).With the method proposed previously,this problem was then solved numerically.Moreover,the dispersion group velocity of the lowest order mode with different initial pressures was also studied.It can be concluded that the initial pressure and the geometry parameters will induce considerable changes of different degrees in dispersive relation between phase velocity and wave number in opposite trend(positive in initial pressure and negative in thickness).
基金Sponsored by the National"973"Program Project(51335030103)
文摘There are few report on the directly measurement of the initial shock pressure of explosive charge at its interface of water for underwater explosion. The special technologies have been taken to the measurement system with manganin piezoresistive gauge （PRG） in order to measure the initial shock pressure at the interface and its near field of TNT chare and water. The free-holding PRG film gauge can directly determine the shock peak pressure at the interface and near field of TNT charge up to 12.85 GPa, which is satisfying for the good agreement to the 12.97 GPa with one dimensional theoretical analysis and 12.86 GPa with numerical simulation. The maximum discrepancy is 0.93 %. The results show that it is precise and reliable to determine the initial shock pressure of underwater explosion charge with the PRG technology.
基金Project supported by the National Natural Science Foundation of China(Grant No.10732010,10972010,and 11028206)
文摘The mechanism of the shift of the band-gap in phononic crystal （PC） with different initial confining pressures is studied experimentally and numerically. The experimental results and numerical analysis simultaneously indicate that the confining pressure can efficiently tune the location in and the width of the band-gap. The present work provides a basis for tuning the band-gap of phononic crystal in engineering applications.
基金the Wider Windows Industrial Affiliate Program,the University of Texas at Austin,for financial and logistical support of this workProgram support from BHP Billiton,British Petroleum,Chevron,Conoco Phillips,Halliburton,Marathon,National Oilwell Varco,Occidental Oil and Gas
文摘Although a large volume of mudcake filtration test data is available in the literature, effects of mudcake on wellbore strengthening cannot be quantified without incorporating the data into a stress-analysis model. Traditional models for determining fracture initiation pressure （FIP） either consider a wellbore with an impermeable mudcake or with no mudcake at all. An analytical model considering permeable mudcake is proposed in this paper. The model can predict pore pressure and stress profiles around the wellbore, and consequently the FIP, for different mudcake thickness, permeability, and strength. Numerical examples are provided to illustrate the effects of these mudcake parameters. The results show that a low-permeability mudcake enhances FIP, mainly through restricting fluid seepage and pore pressure increase in the near- wellbore region, rather than by mudcake strength. Fluid loss pressure （FLP） should be distinguished from FIP when a mudcake is present on the wellbore wall. Fracture may occur behind the mudcake at FIP without mudcake rupture. The small effect of mudcake strength on FIP does not mean its effect on FLP is small too. Mudcake strength may play an important role in maintaining integrity of the wellbore once a fracture has initiated behind the mudcake.
基金Projects(51174228,51174088,51204068,51274097)supported by the National Natural Science Foundation of China
文摘To reveal the water inrush mechanics of underground deep rock mass subjected to dynamic disturbance such as blasting, compression-shear rock crack initiation rule and the evolution of crack tip stress intensity factor are analyzed under static-dynamic loading and seepage water pressure on the basis of theoretical deduction and experimental research. It is shown that the major influence factors of the crack tip stress intensity factor are seepage pressure, dynamic load, static stress and crack angle. The existence of seepage water pressure aggravates propagation of branch cracks. With the seepage pressure increasing, the branch crack experiences unstable extension from stable propagation. The dynamic load in the direction of maximum main stress increases type I crack tip stress intensity factor and its influence on type II crack intensity factor is related with crack angle and material property. Crack initiation angle changes with the dynamic load. The initial crack initiation angle of type I dynamic crack fracture is 70.5°. The compression-shear crack initial strength is related to seepage pressure, confining pressure, and dynamic load. Experimental results verify that the initial crack strength increases with the confining pressure increasing, and decreases with the seepage pressure increasing.
基金Project supported by National Natural Science Foundation
文摘An analytical model of a ring with six yield hinges and two deformable arc segments is presented for. the prediction of the buckle propagation pressure and initiation pressure in offshore pipelines. The configuration of a fully collapsed ring is considered as a real dumbbell shape with a line touch between two 'bells', instead of the dumbbell shape with a point touch of two diametrically opposite points. Calculations are performed assuming that the dominant effect on the plastic energy dissipation has the circumferential bending mode. For the linear strain-hardening materials it is found that theoretical predictions based on the above model for both propagation pressure and initiation nressure are in good agreement with experimental results of Kyriakides et al.
基金Projects(51221001,51272213,51072166)supported by the National Natural Science Foundation of ChinaProject(GBKY1021)supported by the Fundamental Research Foundation of Northwestern Polytechnical University,ChinaProject(B08040)supported by Program of Introducing Talents of Discipline to Universities,China
文摘In order to protect C/C composites from oxidation, SiC-MoSi2 composite coating was synthesized by chemical vapor infiltration /reaction （CVI/CVR） technology. A porous Mo layer was prefabricated on SiC coated C/C composites, and then MoSi2 and SiC were subsequently prepared in a CVI /CVR process using methyltrichlorosilane （MTS） as precursor. The deposition and reaction mechanism of the MoSi2-SiC composite coating was investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The oxidation behavior of SiC-MoSi2 coated specimens was tested. The results show that the porous Mo layer can be densified with SiC phase decomposed from MTS, and transformed into SiC-MoSi2 by reacting with MTS as well. A dense composite coating was prepared with optimized deposition parameters. The coated specimen exhibits a good oxidation resistance with a little mass loss of 1.25% after oxidation at 1500 °C for 80 h.
文摘In this paper the behavior of an O-ring made of NBR rubber was investigated under extreme conditions. The effect of the extreme initial compression, operating pressure and extreme temperature conditions were examined. The rubber material was tested in simple tension, pure shear and equibiaxial tension modes complemented with a Dynamic Mechanical Thermal Analysis (DMTA) to capture the viscoelastic behavior of the material. For the investigation, a large-strain viscoelastic material model was developed by the authors, to take into account the large deformations caused by extreme conditions. Insufficient space during installation causes extreme initial compression consequently leading the material to crack on the contacting outer surfaces. It was found that the excessive strain and friction induced shear stress contributes primarily to this phenomenon. Extreme operating pressure causes the seal to penetrate into the gap between the shaft and the housing. This behavior damages the material and cracks appear on the seal. High strain areas were found in the proximity of the gap in the material. The analysis of the extreme operating temperature showed that during cooling the O-ring can completely loose its ability to seal at -70°C. There are three contributing factors: the speed of cooling, the temperature and the coefficient of thermal expansion.
文摘In this paper, detonation parameters of fuel cloud, such as propylene oxide （PO）, isopropyl nitrate （IPN）, hex- ane, 90# oil and decane were measured in a self-designed and constructed vertical shock tube. Results show that the deto- nation pressure and velocity of PO increase to a peak value and then decrease smoothly with increasing equivalence ra- tio. Several nitrate sensitizers were added into PO to make fuel mixtures, and test results indicated that the additives can efficiently enhance detonation velocity and pressure of fuel cloud and one type of additive n-propyl nitrate （NPN） played the best in the improvement. The critical initiation energy that directly initiated detonation of all the test liquid fuel clouds showed a U-shape curve relationship with equiva- lence ratios. The optimum concentration lies on the rich-fuel side （;b 〉 1）. The critical initiation energy is closely related to molecular structure and volatility of fuels. IPN and PO have similar critical values while that of alkanes are larger. Detonation cell sizes of PO were respectively investigated at 25;C, 35;C and 50;C with smoked foil technique. The cell width shows a U-shape curve relationship with equivalence ratios at all temperatures. The minimal cell width also lies on the rich-fuel side （;b 〉 1）. The cell width of PO vapor is slightly larger than that of PO cloud. Therefore, the deto- nation reaction of PO at normal temperature is controlled by gas phase reaction.
基金Project supported by the National Natural Science Foundation of China,“Microscopic Damage Mechanism of Saturated Brittle Rock during Blasting Induced Fracturing and Its Control Law on Macroscopic Damage”(No.51874339)the Natural Science Foundation of Shandong Province,“Study on the Coupled Response Mechanism of Crack Propagation and Rock Damage in the fracturing condition of multistage strong pulse”(No.ZR2016EEQ04)the Fundamental Research Funds for the Central Universities,China,“Study on the Mechanical Mechanism of Multistage Blasting Induced SRV in Deep-Seated Tight Reservoirs with High Horizontal Stress Difference”(No.17CX05004).
文摘For figuring out the stress interference of multiphase fracture combinations and its effect on the fracture initiation pressure of subsequent hydraulic fracturing,a calculation model for the coupled stress field with multiple induced fractures preexisted was established based on the calculation model for the stress field with single induced fracture preexisted,and the change laws of circumferential stress field around the wellbore under the effect of induced stress were analyzed.Then,the fracture initiation pressure of subsequent hydraulic fracturing was calculated according to the fracturing mechanics criterion.Finally,the effects of the length,phase,horizontal principal stress difference co-efficient and quantity of preexisting fractures on its initiation pressure were analyzed.And the following research results were obtained.First,the circumferential stress difference in the area near the fractures behind the preexisting fractures increase greatly and even the horizontal principal stress is reversed.Second,as the length of new preexisting fractures increases,the initiation pressure of initial preexisting fractures rises first and then drops.And when the length of new preexisting fractures is equal to that of the initial preexisting fractures,the initiation pressure of initial preexisting fractures drops quickly first and then slowly.Third,the initiation pressure of high phase fractures is lower than that of low phase fractures.Fourth,with the increase of fracture quantity,the initiation pressure of new preexisting fractures drops gradually,but the decline trend of initiation pressure difference is not obvious.Fifth,the stress interference of multiphase fractures influences the fracture initiation pressure,and high-phase long fractures and low-phase short fractures are both favorable for the simultaneous initiation of multiphase fractures.Sixth,syn-chronous propagation of multiple fractures can generate more complicated stress interference and excite the evolution of hydraulic fracture network,so as to realize uniform fracturing stimulation.In conclusion,the research results can provide a theoretical guidance for the design of fracturing operation,e.g.perforation phase of blasting induced fracturing,scale of induced fractures,and pump pressure of subsequent hydraulic fracturing.
基金Project supported by the National Major Science and Technology Project“Demonstrative horizontal well development of CBM in Qinshui Basin,Shanxi”(No.:2011ZX05061)PetroChina Major Science and Technology Project“Demonstrative exploration and development of CBM in Qinshui Basin”(No.:2010E-2208)PetroChina Huabei Oilfield Science and Technology Project“Research on efficient development technologies for Mabe East block”(No.:2016-HB-M06).
文摘Low average single-well production resulting in low economic benefit has become the main bottleneck of the CBM gas development in China.So it is significant to choose suitable efficient development technologies based on CBM geological factors for high rank CBM recovery enhancement.In view of this,CBM geological factors were analyzed,different geological models were established and the corresponding models of development engineering technologies were thus put forward.It was proposed that the four main factors affecting high rank CBM recovery from a lower degree to a higher degree respectively include coal texture,rank of coal metamorphism,in-situ stress,and the ratio of critical desorption pressure to initial reservoir pressure.On this basis,four engineering geological models were classified as follows:vertical well,open-hole multilateral horizontal well,U-shaped and roof tree-like horizontal wells,and fish-bone and L-shaped wells.It is concluded that the former two models are more adaptable in such areas with better coal texture and high degree of thermal maturity,while the latter two are commonly applied in a wide range of areas.
基金This research is supported by the Natural Science Fund for Outstanding Youth Science Fund(Grant No.51222406)New Century Excellent Talents in University of China(NCET-12-1061)+2 种基金Scientific Research Innovation Team Project of Sichuan Colleges and Universities(12TD007)the key projects of academic and technical leaders cultivate fund in Sichuan Province,China(2011-441-zxh)Sichuan Science and Technology Innovation Talent Project(20132057).
文摘Horizontal wells show better affect and higher success rate in low water ratio cement,complex fracture zone,crevice and heavy oil blocks,it is the main measures to expand control area of a single well.Hydraulic fracturing technology is the most financial way to improve the penetration of the reservoir to increase the production.However,compare with the vertical wells,the fracture of Horizontal wells are more complex,and lead to the initiation crack pressure is much higher than vertical wells.In this paper,defined the crack judging basis,and established the finite element model which could compute the initial crack pressure,to research the affection mechanism of perforation azimuth angle,density,diameter and depth,to provide references of perforation project's design and optimize.The research of this paper has significances on further understanding the affection mechanism of perforation parameters.
