Azimuth gamma logging while drilling(LWD)is one of the important technologies of geosteering but the information of real-time data transmission is limited and the interpretation is difficult.This study proposes a meth...Azimuth gamma logging while drilling(LWD)is one of the important technologies of geosteering but the information of real-time data transmission is limited and the interpretation is difficult.This study proposes a method of applying artificial intelligence in the LWD data interpretation to enhance the accuracy and efficiency of real-time data processing.By examining formation response characteristics of azimuth gamma ray(GR)curve,the preliminary formation change position is detected based on wavelet transform modulus maxima(WTMM)method,then the dynamic threshold is determined,and a set of contour points describing the formation boundary is obtained.The classification recognition model based on the long short-term memory(LSTM)is designed to judge the true or false of stratum information described by the contour point set to enhance the accuracy of formation identification.Finally,relative dip angle is calculated by nonlinear least square method.Interpretation of azimuth gamma data and application of real-time data processing while drilling show that the method proposed can effectively and accurately determine the formation changes,improve the accuracy of formation dip interpretation,and meet the needs of real-time LWD geosteering.展开更多
Different drill-hole positions may produce different drainage results in low protective coal seams.To investigate this possibility,a 3D stope model is established,which covers three kinds of drill holes.The FLUENT com...Different drill-hole positions may produce different drainage results in low protective coal seams.To investigate this possibility,a 3D stope model is established,which covers three kinds of drill holes.The FLUENT computational fluid mechanics software is used to solve the mass,momentum and species conservation equations of the model.The spatial distributions of oxygen and methane was obtained by calculations and the drainage results of different drill-hole positions were compared.The results show that,from top to bottom,methane dilution by oxygen weakens gradually from the intake to the return side,and methane tends to float;methane and oxygen distribute horizontally.The high-level crossing holes contribute to better methane drainage and a greater level of control.Around these holes,the methane density decreases dramatically and a "half circle"distribution is formed.The methane density decreases on the whole,but a proportion of the methane moves back to deep into the goaf.The research findings provide theoretical grounds for methane drainage.展开更多
Songke Well No.2,one of the main part of the scientific drilling project in Songliao Basin,which was drilled 7018 m and acquired the part of cores continuously from the Low Cretaceous to the Carboniferous and the Perm...Songke Well No.2,one of the main part of the scientific drilling project in Songliao Basin,which was drilled 7018 m and acquired the part of cores continuously from the Low Cretaceous to the Carboniferous and the Permian from the 2843 m deep,can be considered as the deepest continental drilling project in Asia.Aiming at the features of longer well sections,larger diameters and multiple spud-ins for coring of Songke Well No.2,this project broke through the "coring in small diameter and reaming in large diameter"spud-in drilling-completion procedures which are always used in large-diameter-well coring for continental scientific drilling projects in domestic and overseas and the drilling method of short-singlecylinder roundtrip footage.At the same time,"coring in the same diameter and completing drilling at one single diameter"was achieved at all φ311 mm and φ216 mm coring sections of more than one thousand meters long,high-efficient operation with "drilling long footage with drill tools combined in multicylinders"was achieved at deep coring section.Four world drilling records were created which include more than a thousand meters continuous coring at φ311 mm,and the footage per roundtrip footage at φ311 mm,φ216 mm and φ152 mm is all more than 30 m,all of these breakthroughs reduced at least 300 days for this project;moreover,considering the characteristics of formations that the geothermal gradient is high in the drilled sections and the inside-well temperature is over 240℃ after drilling completion,a formate-polymer water-based mud system was developed by compounding attapulgite and sodium bentonite and by adding independently developed high-temperature stabilizer,which can provide critical technical support for successful well completion at 7018 m in the super-high-temperature environment It is the first time that the water-based mud is operated at the working temperature higher than 240℃ in China;Besides,considering the high-quality requirement on cores imposed by the project,the method "mechanical cored is charge"to discharge core nondestructively on the ground was worked out,and more than 4000 m scatheless cores were discharged out of the drill pipes while maintaining original stratum structures.展开更多
基金Supported by the PetroChina Major Scientific and Technological Project(ZD2019-183-006)Fundamental Scientific Research Fund of Central Universities(20CX05017A)China National Science and Technology Major Project(2016ZX05021-001)。
文摘Azimuth gamma logging while drilling(LWD)is one of the important technologies of geosteering but the information of real-time data transmission is limited and the interpretation is difficult.This study proposes a method of applying artificial intelligence in the LWD data interpretation to enhance the accuracy and efficiency of real-time data processing.By examining formation response characteristics of azimuth gamma ray(GR)curve,the preliminary formation change position is detected based on wavelet transform modulus maxima(WTMM)method,then the dynamic threshold is determined,and a set of contour points describing the formation boundary is obtained.The classification recognition model based on the long short-term memory(LSTM)is designed to judge the true or false of stratum information described by the contour point set to enhance the accuracy of formation identification.Finally,relative dip angle is calculated by nonlinear least square method.Interpretation of azimuth gamma data and application of real-time data processing while drilling show that the method proposed can effectively and accurately determine the formation changes,improve the accuracy of formation dip interpretation,and meet the needs of real-time LWD geosteering.
基金The authors gratefully acknowledge the financial support of the 2013 Science and Technological Projects of Henan Province(132102210448).
文摘Different drill-hole positions may produce different drainage results in low protective coal seams.To investigate this possibility,a 3D stope model is established,which covers three kinds of drill holes.The FLUENT computational fluid mechanics software is used to solve the mass,momentum and species conservation equations of the model.The spatial distributions of oxygen and methane was obtained by calculations and the drainage results of different drill-hole positions were compared.The results show that,from top to bottom,methane dilution by oxygen weakens gradually from the intake to the return side,and methane tends to float;methane and oxygen distribute horizontally.The high-level crossing holes contribute to better methane drainage and a greater level of control.Around these holes,the methane density decreases dramatically and a "half circle"distribution is formed.The methane density decreases on the whole,but a proportion of the methane moves back to deep into the goaf.The research findings provide theoretical grounds for methane drainage.
文摘Songke Well No.2,one of the main part of the scientific drilling project in Songliao Basin,which was drilled 7018 m and acquired the part of cores continuously from the Low Cretaceous to the Carboniferous and the Permian from the 2843 m deep,can be considered as the deepest continental drilling project in Asia.Aiming at the features of longer well sections,larger diameters and multiple spud-ins for coring of Songke Well No.2,this project broke through the "coring in small diameter and reaming in large diameter"spud-in drilling-completion procedures which are always used in large-diameter-well coring for continental scientific drilling projects in domestic and overseas and the drilling method of short-singlecylinder roundtrip footage.At the same time,"coring in the same diameter and completing drilling at one single diameter"was achieved at all φ311 mm and φ216 mm coring sections of more than one thousand meters long,high-efficient operation with "drilling long footage with drill tools combined in multicylinders"was achieved at deep coring section.Four world drilling records were created which include more than a thousand meters continuous coring at φ311 mm,and the footage per roundtrip footage at φ311 mm,φ216 mm and φ152 mm is all more than 30 m,all of these breakthroughs reduced at least 300 days for this project;moreover,considering the characteristics of formations that the geothermal gradient is high in the drilled sections and the inside-well temperature is over 240℃ after drilling completion,a formate-polymer water-based mud system was developed by compounding attapulgite and sodium bentonite and by adding independently developed high-temperature stabilizer,which can provide critical technical support for successful well completion at 7018 m in the super-high-temperature environment It is the first time that the water-based mud is operated at the working temperature higher than 240℃ in China;Besides,considering the high-quality requirement on cores imposed by the project,the method "mechanical cored is charge"to discharge core nondestructively on the ground was worked out,and more than 4000 m scatheless cores were discharged out of the drill pipes while maintaining original stratum structures.
