This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas p...This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas production engineering in terms of technological adaptability,digital construction,energy-saving and emission reduction,and points out the future development direction.During the"Thirteenth Five-Year Plan"period,series of important progresses have been made in five major technologies,including separated-layer injection,artificial lift,reservoir stimulation,gas well de-watering,and workover,which provide key technical support for continuous potential tapping of mature oilfields and profitable production of new oilfields.Under the current complex international political and economic situation,oil and gas production engineering is facing severe challenges in three aspects:technical difficulty increases in oil and gas production,insignificant improvements in digital transformation,and lack of core technical support for energy-saving and emission reduction.This paper establishes three major strategic directions and implementation paths,including oil stabilization and gas enhancement,digital transformation,and green and low-carbon development.Five key research areas are listed including fine separated-layer injection technology,high efficiency artificial lift technology,fine reservoir stimulation technology,long term gas well de-watering technology and intelligent workover technology,so as to provide engineering technical support for the transformation,upgrading and high-quality development of China’s oil and gas industry.展开更多
The Qiangtang Basin of the Tibetan Plateau,located in the eastern Tethys tectonic domain,is the largest new marine petroliferous region for exploration in China.The scientific drilling project consisting primarily of ...The Qiangtang Basin of the Tibetan Plateau,located in the eastern Tethys tectonic domain,is the largest new marine petroliferous region for exploration in China.The scientific drilling project consisting primarily of well QK-1 and its supporting shallow boreholes for geological surveys(also referred to as the Project)completed in recent years contributes to a series of new discoveries and insights into the oil and gas preservation conditions and source rock evaluation of the Qiangtang Basin.These findings differ from previous views that the Qiangtang Basin has poor oil and gas preservation conditions and lacks high-quality source rocks.As revealed by well QK-1 and its supporting shallow boreholes in the Project,the Qiangtang Basin hosts two sets of high-quality regional seals,namely an anhydrite layer in the Quemo Co Formation and the gypsum-bearing mudstones in the Xiali Formation.Moreover,the Qiangtang Basin has favorable oil and gas preservation conditions,as verified by the comprehensive study of the sealing capacity of seals,basin structure,tectonic uplift,magmatic activity,and groundwater motion.Furthermore,the shallow boreholes have also revealed that the Qiangtang Basin has high-quality hydrocarbon source rocks in the Upper Triassic Bagong Formation,which are thick and widely distributed according to the geological and geophysical data.In addition,the petroleum geological conditions,such as the type,abundance,and thermal evolution of organic matter,indicate that the Qiangtang Basin has great hydrocarbon-generating potential.展开更多
To meet the requirements of marine natural gas hydrate exploitation,it is necessary to improve the penetration of completion sand control string in the large curvature borehole.In this study,large curvature test wells...To meet the requirements of marine natural gas hydrate exploitation,it is necessary to improve the penetration of completion sand control string in the large curvature borehole.In this study,large curvature test wells were selected to carry out the running test of sand control string with pre-packed screen.Meanwhile,the running simulation was performed by using the Landmark software.The results show that the sand control packer and screen can be run smoothly in the wellbore with a dogleg angle of more than 20°/30 m and keep the structure stable.Additionally,the comprehensive friction coefficient is 0.4,under which and the simulation shows that the sand control string for hydrate exploitation can be run smoothly.These findings have important guiding significance for running the completion sand control string in natural gas hydrate exploitation.展开更多
Oil and gas resources are short in Pakistan and no commercially viable oil and gas sources have been yet discovered in its offshore areas up to now.In this study,the onshore-offshore stratigraphic correlation and seis...Oil and gas resources are short in Pakistan and no commercially viable oil and gas sources have been yet discovered in its offshore areas up to now.In this study,the onshore-offshore stratigraphic correlation and seismic data interpretation were conducted to determine the oil and gas resource potential in the Offshore Indus Basin,Pakistan.Based on the comprehensive analysis of the results and previous data,it is considered that the Cretaceous may widely exist and three sets of source rocks may be developed in the Offshore Indus Basin.The presence of Miocene mudstones has been proven by drilling to be high-quality source rocks,while the Cretaceous and Paleocene–Eocene mudstones are potential source rocks.Tectonic-lithologic traps are developed in the northwestern part of the basin affected by the strike-slip faults along Murray Ridge.Furthermore,the Cretaceous and Paleocene–Eocene source rocks are thick and are slightly affected by volcanic activities.Therefore,it can be inferred that the northwestern part of Offshore Indus Basin enjoys good prospects of oil and gas resources.展开更多
The Daqing exploration area in the northern Songliao Basin has great potential for unconventional oil and gas resources,among which the total resources of tight oil alone exceed 109 t and is regarded as an important r...The Daqing exploration area in the northern Songliao Basin has great potential for unconventional oil and gas resources,among which the total resources of tight oil alone exceed 109 t and is regarded as an important resource base of Daqing oilfield.After years of exploration in the Qijia area,Songliao Basin,NE China,tight oil has been found in the Upper Cretaceous Qingshankou Formation.To work out tight oil’s geological characteristics,taking tight oil in Gaotaizi oil layers of the Upper Cretaceous Qingshankou Formation in northern Songliao Basin as an example,this paper systematically analyzed the geological characteristics of unconventional tight oil in Gao3 and Gao4 layers of the Qijia area,based on the data of the geological survey,well drilling journey,well logging,and test.It is that three sets of hydrocarbon source rocks(K2qn1,K2qn2+3,and K2n1)develop in the examined area,and exhibit excellent type I and II kerogens,high organic matter abundance,and moderate maturity.The reservoir is generally composed of thin-bedded mudstone,siltstone,and sandstone,and presents poor porosity(average 8.5 vol.%)and air permeability(average 4 mD).The main reservoir space primarily includes intergranular pores,secondary soluble pores,and intergranular soluble pores.Three types of orifice throats were identified,namely fine throat,extra-fine throat,and micro-fine throat.The siltstone is generally oil-bearing,the reservoirs with slime and calcium become worse oil-bearing,and the mudstone has no obvious oil-bearing characteristics.The brittleness indices of the sandstone in the tight oil reservoir range from 40%to 60%,and those of the mudstone range from 40%to 45%,indicating a better brittleness of the tight oil reservoir.Based on the study of typical core hole data,this paper gives a comprehensive evaluation of the properties of the tight oil and establishes a tight oil single well composite bar chart as well as the initial evaluation system with the core of properties in the tight oil reservoir.This study has theoretical guiding significance and practical application value for tight oil exploration and evaluation in the Qijia area.展开更多
Shenhu Area is located in the Baiyun Sag of Pearl River Mouth Basin,which is on the northern continental slope of the South China Sea.Gas hydrates in this area have been intensively investigated,achieving a wide cover...Shenhu Area is located in the Baiyun Sag of Pearl River Mouth Basin,which is on the northern continental slope of the South China Sea.Gas hydrates in this area have been intensively investigated,achieving a wide coverage of the three-dimensional seismic survey,a large number of boreholes,and detailed data of the seismic survey,logging,and core analysis.In the beginning of 2020,China has successfully conducted the second offshore production test of gas hydrates in this area.In this paper,studies were made on the structure of the hydrate system for the production test,based on detailed logging data and core analysis of this area.As to the results of nuclear magnetic resonance(NMR)logging and sonic logging of Well GMGS6-SH02 drilled during the GMGS6 Expedition,the hydrate system on which the production well located can be divided into three layers:(1)207.8–253.4 mbsf,45.6 m thick,gas hydrate layer,with gas hydrate saturation of 0–54.5%(31%av.);(2)253.4–278 mbsf,24.6 m thick,mixing layer consisting of gas hydrates,free gas,and water,with gas hydrate saturation of 0–22%(10%av.)and free gas saturation of 0–32%(13%av.);(3)278–297 mbsf,19 m thick,with free gas saturation of less than 7%.Moreover,the pore water freshening identified in the sediment cores,taken from the depth below the theoretically calculated base of methane hydrate stability zone,indicates the occurrence of gas hydrate.All these data reveal that gas hydrates,free gas,and water coexist in the mixing layer from different aspects.展开更多
NiCoCrAlYTa coatings have been deposited onto an aircraft gas turbine engine blade using a LPPS unit equipped with a computerized robot. Optimal processing conditions, including spray parameters, the trajectory of the...NiCoCrAlYTa coatings have been deposited onto an aircraft gas turbine engine blade using a LPPS unit equipped with a computerized robot. Optimal processing conditions, including spray parameters, the trajectory of the robot, and the synchronized movements between the torch and the blade, have been developed for superior coating properties. Transferred arc treatment, providing a preheating and a cleaning of the substrate surface, enhances the adherence of the coatings to the substrate. The resulting LPPS coatings show dense and uniform characteristics with ideal hardness, and good corrosion resistance to cycle oxidation.展开更多
A variable nozzle turbocharger (VNT) was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in whic...A variable nozzle turbocharger (VNT) was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in which VNT adjustment is carried out through pre-calibrated VNT handling rod position,combined with a closed-loop target boost pressure feedback using proportional-integral-derivative(PID) algorithm.Experimental results showed that the VNT control system presented in this thesis can lead to optimized performance of VNT,increase engine volumetric efficiency over a wide speed range,improve engine dynamic characteristics and upgrade economic performance.展开更多
The permeability of a natural gas hydrate reservoir is a critical parameter associated with gas hydrate production.Upon producing gas from a hydrate reservoir via depressurization,the permeability of sediments changes...The permeability of a natural gas hydrate reservoir is a critical parameter associated with gas hydrate production.Upon producing gas from a hydrate reservoir via depressurization,the permeability of sediments changes in two ways with hydrate dissociation,increasing with more pore space released from hydrate and decreasing due to pore compression by stronger effective stress related to depressurization.In order to study the evolution of sediment permeability during the production process with the depressurization method,an improved pore network model(PNM)method is developed to establish the permeability change model.In this model,permeability change induced by hydrate dissociation is investigated under hydrate occurrence morphology of pore filling and grain coating.The results obtained show that hydrate occurrence in sediment pore is with significant influence on permeability change.Within a reasonable degree of pore compression in field trial,the effect of pore space release on the reservoir permeability is greater than that of pore compression.The permeability of hydrate containing sediments keeps increasing in the course of gas production,no matter with what hydrate occurrence in sediment pore.展开更多
In order to evaluate the geological characteristics and gas-bearing factors of Niutitang Formation within the Lower Cambrian of northern Guizhou,the Huangping area located at the southern edge of the ancient uplift be...In order to evaluate the geological characteristics and gas-bearing factors of Niutitang Formation within the Lower Cambrian of northern Guizhou,the Huangping area located at the southern edge of the ancient uplift belt of Xuefeng Mountain was selected as the target area,and Well Huangdi 1 was drilled for the geological survey of shale gas.Through geological background analysis and well logging and laboratory analysis such as organic geochemical test,gas content analysis,isothermal adsorption,and specific surface area experiments on Well Huangdi 1,the results show that the Niutitang Formation is a deep-water shelf,trough-like folds and thrust fault.The thickness of black shale is 119.95 m,of which carbonaceous shale is 89.6 m.The average value of organic carbon content is 3.55%,kerogen vitrinite reflectance value is 2.37% and kerogen type is sapropel-type.The brittle mineral content is 51%(quartz 38%),clay mineral content is 38.3%.The value of porosity and permeability are 0.5%and 0.0014 mD,which the reservoir of the Niutitang Formation belongs to low permeability with characteristics of ultra-low porosity.The gas content is 0.09‒1.31 m^3/t with a high-value area and a second high-value area.By comparing with the geological parameters of adjacent wells in the adjacent area,the accumulation model of“sediment control zone,Ro control zone,structure controlling reservoir”in the study area is proposed.Therefore,deep-water shelf-slope facies,Ro is between high maturity-early stage of overmaturity and well-preserved zones in the Niutitang Formation in this area are favorable direction for the next step of shale gas exploration.展开更多
The Sichuan Basin is one of the vital basins in China,boasting abundant hydrocarbon reservoirs.To clarify the intensity of the tectonic stress field of different tectonic episodes since the Mesozoic and to identify th...The Sichuan Basin is one of the vital basins in China,boasting abundant hydrocarbon reservoirs.To clarify the intensity of the tectonic stress field of different tectonic episodes since the Mesozoic and to identify the regional dynamic background of different tectonic movements in the Sichuan Basin and its adjacent areas,the characteristics of the acoustic emission in rocks in different strata of these areas were researched in this paper.Meanwhile,the tectonic stress magnitude in these areas since the Mesozoic was restored.The laws state that the tectonic stress varied with depth was revealed,followed by the discussion of the influence of structural stress intensity on structural patterns in different tectonic episodes.These were conducted based on the paleostress measurement by acoustic emission method and the inversion principle of the stress fields in ancient periods and the present,as well as previous research achievements.The results of this paper demonstrate that the third episode of Yanshanian Movement(Yanshanian III)had the maximum activity intensity and tremendously influenced the structural pattern in the study area.The maximum horizontal principal stress of Yanshanian III varied with depth as follows:0.0168 x+37.001(MPa),R^2=0.8891.The regional structural fractures were mainly formed in Yanshanian III in Xujiahe Formation,west Sichuan Basin,of which the maximum paleoprincipal stress ranging from 85.1 MPa to 120.1 MPa.In addition,the law stating the present maximum horizontal principal stress varies with depth was determined to be 0.0159 x+10.221(MPa),R^2=0.7868 in Wuling Mountain area.Meanwhile,it was determined to be 0.0221 x+9.4733(MPa),R^2=0.9121 in the western part of Xuefeng Mountain area and 0.0174 x+10.247(MPa),R^2=0.8064 in the whole study area.These research results will not only provide data for the simulation of stress field,the evaluation of deformation degree,and the prediction of structural fractures,but also offer absolute geological scientific bases for the elevation of favorable shale gas preservation.展开更多
Traditional suction anchor technology is mainly used in the fields of subsea structure bearing foundations,single-point mooring systems and offshore wind power.It is characterized by providing sufficient lateral and v...Traditional suction anchor technology is mainly used in the fields of subsea structure bearing foundations,single-point mooring systems and offshore wind power.It is characterized by providing sufficient lateral and vertical bearing capacities and lateral bending moment.The anchor structure of a traditional suction anchor structure is improved with wellhead suction anchor technology,where a central pipe is added as a channel for drilling and completion operations.To solve the technical problems of a low wellhead bearing capacity,shallow built-up depth,and limited application of conductor jetting in the second production test of natural gas hydrates(NGHs)in the South China Sea(SCS),the China Geological Survey(CGS)took the lead in independently designing and manufacturing a wellhead suction anchor,which fulfilled the requirements of the production test.This novel anchor was successfully implemented in the second production test for the first time,providing a stable wellhead foundation for the success of the second production test of NGHs in the SCS.展开更多
The composition of gas released under vacuum by crushing from the gas shale of Longmaxi Formation in Upper Yangtze Plate,Southern China was systematically investigated in this study.The effect of residual gas release ...The composition of gas released under vacuum by crushing from the gas shale of Longmaxi Formation in Upper Yangtze Plate,Southern China was systematically investigated in this study.The effect of residual gas release on pore structures was checked using low-pressure nitrogen adsorption techniques.The influence of particle size on the determination of pore structure characteristics was considered.Using the Frenkel-Halsey-Hill method from low-pressure nitrogen adsorption data,the fractal dimensions were identified at relative pressures of 0‒0.5 and 0.5‒1 as D1 and D2,respectively,and the evolution of fractal features related to gas release was also discussed.The results showed that a variety component of residual gas was released from all shale samples,containing hydrocarbon gas of CH4(29.58%‒92.53%),C2H6(0.97%‒2.89%),C3H8(0.01%‒0.65%),and also some non-hydrocarbon gas such as CO2(3.54%‒67.09%)and N2(1.88%‒8.07%).The total yield of residual gas was in a range from 6.1μL/g to 17.0μL/g related to rock weight.The geochemical and mineralogical analysis suggested that the residual gas yield was positively correlated with quartz(R^2=0.5480)content.The residual gas released shale sample has a higher surface area of 17.20‒25.03 m^2/g and the nitrogen adsorption capacity in a range of 27.32‒40.86 ml/g that is relatively higher than the original samples(with 9.22‒16.30 m^2/g and 10.84‒17.55 ml/g).Clearer hysteresis loop was observed for the original shale sample in nitrogen adsorption-desorption isotherms than residual gas released sample.Pore structure analysis showed that the proportions of micro-,meso-and macropores were changed as micropores decreased while meso-and macropores increased.The fractal dimensions D1 were in range from 2.5466 to 2.6117 and D2 from 2.6998 to 2.7119 for the residual gas released shale,which is smaller than the original shale.This factor may indicate that the pore in residual gas released shale was more homogeneous than the original shale.The results indicated that both residual gas and their pore space have few contributions to shale gas production and effective reservoir evaluation.The larger fragments samples of granular rather than powdery smaller than 60 mesh fraction of shale seem to be better for performing effective pore structure analysis to the Longmaxi shale.展开更多
Various factors controlling the accumulation of natural gas hydrates(NGHs)form various enrichment and accumulation modes through organic combination.This study mainly analyzes the geological and geophysical characteri...Various factors controlling the accumulation of natural gas hydrates(NGHs)form various enrichment and accumulation modes through organic combination.This study mainly analyzes the geological and geophysical characteristics of the NGHs occurrence in the uplifts and their slope zones within the deep-water area in the Qiongdongnan(QDN)Basin(also referred to as the study area).Furthermore,it investigates the dominant governing factors and models of NGHs migration and accumulation in the study area.The results are as follows.(1)The uplifts and their slope zones in the study area lie in the dominant pressure-relief direction of fluids in central hydrocarbon-rich sags in the area,which provide sufficient gas sources for the NGHs accumulation and enrichment through pathways such as gas chimneys and faults.(2)The top and flanks of gas chimneys below the bottom simulating reflectors(BSRs)show high-amplitude seismic reflections and pronounced transverse charging of free gas,indicating the occurrence of a large amount of gas accumulation at the heights of the uplifts.(3)Chimneys,faults,and high-porosity and high-permeability strata,which connect the gas hydrate temperature-pressure stability zones(GHSZs)with thermogenic gas and biogenic gas,form the main hydrate migration system.(4)The reservoir system in the study area comprises sedimentary interlayers consisting of mass transport deposits(MTDs)and turbidites.In addition,the reservoir system has developed fissure-and pore-filling types of hydrates in the pathways.The above well-matched controlling factors of hydrate accumulation enable the uplifts and their slope zones in the study area to become the favorable targets of NGHs exploration.展开更多
North Carnarvon Basin is a gas province with minor oily sweet spots in deepwater area with water depth more than 500 m,which is one of the hot spots of global petroleum exploration for its series of giant hydrocarbon ...North Carnarvon Basin is a gas province with minor oily sweet spots in deepwater area with water depth more than 500 m,which is one of the hot spots of global petroleum exploration for its series of giant hydrocarbon discoveries in recent years.However,the degree of oil and gas exploration in deepwater area is still low,and the conditions for oil and gas accumulation are not clear.Based on the current exploration situation and latest database of fields,applying multidisciplinary analysis of hydrocarbon geology,hydrocarbon accumulation elements and its exploration direction of North Carnarvon Basin in deepwater area are analyzed.The results show that there are three sets of main source rocks in deepwater area of North Carnarvon Basin,which are Triassic marine shale in Locker Formation and delta coal-bearing mudstone with thin carbonaceous mudstone in Mungaroo Formation,Lower–Middle Jurassic paralic carbargilite and coal measure strata in Athol Formation and Murat Formation,Cretaceous delta mudstone in Barrow Group and marine shale in Muderong Formation.Most source rock samples show gas-prone capability.The coarse sandstone of delta facies in Middle–Upper Triassic Mungaroo Formation is the most important reservoir in deepwater area,Lower Cretaceous Barrow Group deep-water gravity flow or underwater fan turbidite sandstone is the secondly main reservoir.Lower Cretaceous marine shale in Muderong Formation is most important regional caprock.Triassic mudstone in Mungaroo Formation is an important interlayer caprock in deepwater area.There are two main reservoir accumulation assemblages in deepwater area,one is Triassic structural-unconformity plane reservoir accumulation assemblage of Locker Formation to Mungaroo Formation,and the other is Lower–Middle Jurassic Athol Formation and Murat Formation–Lower Cretaceous stratigraphic lithology-structural reservoir accumulation assemblage of Barrow Group to Muderong Formation.There are three main control factors of hydrocarbon Accumulation:One is coupling of source and seal control hydrocarbon distribution area,the second is multi-stage large wave dominated deltas dominate accumulation zone,the third is direction of hydrocarbon migration and accumulation in hydrocarbon-rich generation depression was controlled by overpressure.The south of Exmouth platform in deepwater area is adjacent to hydrocarbon rich depression zone,reservoir assemblage is characterized by“near source rocks,excellent reservoir facies,high position and excellent caprocks”,which is the main battlefield of deepwater oil and gas exploration in North Carnarvon Basin at present.There are a lot of fault block traps in the northern structural belt of Exmouth platform,and the favorable sedimentary facies belt at the far end of delta plain in Mungaroo Formation is widely distributed,which is the next favorable exploration zone.The Lower Cretaceous,which is located at the concave edge uplift adjacent to the investigator depression and the Exmouth platform,also has a certain exploration prospect in northwest of deepwater area.展开更多
A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted ...A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted in improved activities of the fresh and aged catalyst by lowering the light-off temperature for methane in natural gas engines exhaust.展开更多
Natural gas hydrates(NGHs)are a new type of clean energy with great development potential.However,it is urgent to achieve safe and economical NGHs development and utilization.This study established a physical model of...Natural gas hydrates(NGHs)are a new type of clean energy with great development potential.However,it is urgent to achieve safe and economical NGHs development and utilization.This study established a physical model of the study area using the FLAC^(3D) software based on the key parameters of the NGHs production test area in the South China Sea,including the depressurization method,and mechanical parameters of strata,NGHs occurrence characteristics,and the technological characteristics of horizontal wells.Moreover,this study explored the law of influences of the NGHs dissociation range on the stability of the overburden strata and the casing structure of a horizontal well.The results are as follows.With the dissociation of NGHs,the overburden strata of the NGHs dissociation zone subsided and formed funnelshaped zones and then gradually stabilized.However,the upper interface of the NGHs dissociation zone showed significant redistribution and discontinuity of stress.Specifically,distinct stress concentration and corresponding large deformation occurred in the build-up section of the horizontal well,which was thus prone to suffering shear failure.Moreover,apparent end effects occurred at the end of the horizontal well section and might cause the deformation and failure of the casing structure.Therefore,it is necessary to take measures in the build-up section and at the end of the horizontal section of the horizontal well to prevent damage and ensure the wellbore safety in the long-term NGHs exploitation.展开更多
基金Supported by the Basic Science Center Project of National Natural Science Foundation of China(72088101)National Natural Science Funded Project(52074345)CNPC Scientific Research and Technology Development Project(2020D-5001-21)。
文摘This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas production engineering in terms of technological adaptability,digital construction,energy-saving and emission reduction,and points out the future development direction.During the"Thirteenth Five-Year Plan"period,series of important progresses have been made in five major technologies,including separated-layer injection,artificial lift,reservoir stimulation,gas well de-watering,and workover,which provide key technical support for continuous potential tapping of mature oilfields and profitable production of new oilfields.Under the current complex international political and economic situation,oil and gas production engineering is facing severe challenges in three aspects:technical difficulty increases in oil and gas production,insignificant improvements in digital transformation,and lack of core technical support for energy-saving and emission reduction.This paper establishes three major strategic directions and implementation paths,including oil stabilization and gas enhancement,digital transformation,and green and low-carbon development.Five key research areas are listed including fine separated-layer injection technology,high efficiency artificial lift technology,fine reservoir stimulation technology,long term gas well de-watering technology and intelligent workover technology,so as to provide engineering technical support for the transformation,upgrading and high-quality development of China’s oil and gas industry.
基金funded by projects of the National Natural Science Foundation of China(91955204,42241202)the Second Tibetan Plateau Scientific Expedition and Research(2019QZKK080301)a project entitled Tectonics,Sedimentation,Evolution,and Basic Petroleum Geology of the Qiangtang Basin(2021DJ0801)of the Forward-looking Basic Subjects of PetroChina’s 14th Five-Year Plan.
文摘The Qiangtang Basin of the Tibetan Plateau,located in the eastern Tethys tectonic domain,is the largest new marine petroliferous region for exploration in China.The scientific drilling project consisting primarily of well QK-1 and its supporting shallow boreholes for geological surveys(also referred to as the Project)completed in recent years contributes to a series of new discoveries and insights into the oil and gas preservation conditions and source rock evaluation of the Qiangtang Basin.These findings differ from previous views that the Qiangtang Basin has poor oil and gas preservation conditions and lacks high-quality source rocks.As revealed by well QK-1 and its supporting shallow boreholes in the Project,the Qiangtang Basin hosts two sets of high-quality regional seals,namely an anhydrite layer in the Quemo Co Formation and the gypsum-bearing mudstones in the Xiali Formation.Moreover,the Qiangtang Basin has favorable oil and gas preservation conditions,as verified by the comprehensive study of the sealing capacity of seals,basin structure,tectonic uplift,magmatic activity,and groundwater motion.Furthermore,the shallow boreholes have also revealed that the Qiangtang Basin has high-quality hydrocarbon source rocks in the Upper Triassic Bagong Formation,which are thick and widely distributed according to the geological and geophysical data.In addition,the petroleum geological conditions,such as the type,abundance,and thermal evolution of organic matter,indicate that the Qiangtang Basin has great hydrocarbon-generating potential.
基金supported jointly by one of the major projects of Basic and Applied Basic Research in Guangdong Province“Key Basic Theory Research for Natural Gas Hydrate Trial Production in Shenhu Pilot Test Area”(2020B0301030003)the project from Southern Marine Science&Engineering Guangdong Laboratory Guangzhou City“Research on New Closed Circulation Drilling Technology without Riser”(GML2019ZD0501)the special project for hydrate from China Geological Survey“Trial Production Implementation for Natural Gas Hydrate in Shenhu Pilot Test Area”(DD20190226)。
文摘To meet the requirements of marine natural gas hydrate exploitation,it is necessary to improve the penetration of completion sand control string in the large curvature borehole.In this study,large curvature test wells were selected to carry out the running test of sand control string with pre-packed screen.Meanwhile,the running simulation was performed by using the Landmark software.The results show that the sand control packer and screen can be run smoothly in the wellbore with a dogleg angle of more than 20°/30 m and keep the structure stable.Additionally,the comprehensive friction coefficient is 0.4,under which and the simulation shows that the sand control string for hydrate exploitation can be run smoothly.These findings have important guiding significance for running the completion sand control string in natural gas hydrate exploitation.
基金This work was financially supported by National Natural Science Foundation of China(91858208,41406080,42076069)China Geological Survey(DD20190581).
文摘Oil and gas resources are short in Pakistan and no commercially viable oil and gas sources have been yet discovered in its offshore areas up to now.In this study,the onshore-offshore stratigraphic correlation and seismic data interpretation were conducted to determine the oil and gas resource potential in the Offshore Indus Basin,Pakistan.Based on the comprehensive analysis of the results and previous data,it is considered that the Cretaceous may widely exist and three sets of source rocks may be developed in the Offshore Indus Basin.The presence of Miocene mudstones has been proven by drilling to be high-quality source rocks,while the Cretaceous and Paleocene–Eocene mudstones are potential source rocks.Tectonic-lithologic traps are developed in the northwestern part of the basin affected by the strike-slip faults along Murray Ridge.Furthermore,the Cretaceous and Paleocene–Eocene source rocks are thick and are slightly affected by volcanic activities.Therefore,it can be inferred that the northwestern part of Offshore Indus Basin enjoys good prospects of oil and gas resources.
基金funded by the shale oil and gas geological survey project in Quemoco sag,Qiangtang Basin of China Geological Survey(DD20221855,DD20230315).
文摘The Daqing exploration area in the northern Songliao Basin has great potential for unconventional oil and gas resources,among which the total resources of tight oil alone exceed 109 t and is regarded as an important resource base of Daqing oilfield.After years of exploration in the Qijia area,Songliao Basin,NE China,tight oil has been found in the Upper Cretaceous Qingshankou Formation.To work out tight oil’s geological characteristics,taking tight oil in Gaotaizi oil layers of the Upper Cretaceous Qingshankou Formation in northern Songliao Basin as an example,this paper systematically analyzed the geological characteristics of unconventional tight oil in Gao3 and Gao4 layers of the Qijia area,based on the data of the geological survey,well drilling journey,well logging,and test.It is that three sets of hydrocarbon source rocks(K2qn1,K2qn2+3,and K2n1)develop in the examined area,and exhibit excellent type I and II kerogens,high organic matter abundance,and moderate maturity.The reservoir is generally composed of thin-bedded mudstone,siltstone,and sandstone,and presents poor porosity(average 8.5 vol.%)and air permeability(average 4 mD).The main reservoir space primarily includes intergranular pores,secondary soluble pores,and intergranular soluble pores.Three types of orifice throats were identified,namely fine throat,extra-fine throat,and micro-fine throat.The siltstone is generally oil-bearing,the reservoirs with slime and calcium become worse oil-bearing,and the mudstone has no obvious oil-bearing characteristics.The brittleness indices of the sandstone in the tight oil reservoir range from 40%to 60%,and those of the mudstone range from 40%to 45%,indicating a better brittleness of the tight oil reservoir.Based on the study of typical core hole data,this paper gives a comprehensive evaluation of the properties of the tight oil and establishes a tight oil single well composite bar chart as well as the initial evaluation system with the core of properties in the tight oil reservoir.This study has theoretical guiding significance and practical application value for tight oil exploration and evaluation in the Qijia area.
基金Jointly funded by a major research plan of National Natural Science Foundation of China(51991365)titled“Multi-Field Spatial-Temporal Evolution Laws of Phase Transition and Seepage of Natural Gas Hydrate in Reservoirs”and a geological survey project initiated by China Geological Survey(DD20190226)titled“Implementation of Natural Gas Hydrate Production Test in Pilot Test Area in Shenhu Area”.
文摘Shenhu Area is located in the Baiyun Sag of Pearl River Mouth Basin,which is on the northern continental slope of the South China Sea.Gas hydrates in this area have been intensively investigated,achieving a wide coverage of the three-dimensional seismic survey,a large number of boreholes,and detailed data of the seismic survey,logging,and core analysis.In the beginning of 2020,China has successfully conducted the second offshore production test of gas hydrates in this area.In this paper,studies were made on the structure of the hydrate system for the production test,based on detailed logging data and core analysis of this area.As to the results of nuclear magnetic resonance(NMR)logging and sonic logging of Well GMGS6-SH02 drilled during the GMGS6 Expedition,the hydrate system on which the production well located can be divided into three layers:(1)207.8–253.4 mbsf,45.6 m thick,gas hydrate layer,with gas hydrate saturation of 0–54.5%(31%av.);(2)253.4–278 mbsf,24.6 m thick,mixing layer consisting of gas hydrates,free gas,and water,with gas hydrate saturation of 0–22%(10%av.)and free gas saturation of 0–32%(13%av.);(3)278–297 mbsf,19 m thick,with free gas saturation of less than 7%.Moreover,the pore water freshening identified in the sediment cores,taken from the depth below the theoretically calculated base of methane hydrate stability zone,indicates the occurrence of gas hydrate.All these data reveal that gas hydrates,free gas,and water coexist in the mixing layer from different aspects.
文摘NiCoCrAlYTa coatings have been deposited onto an aircraft gas turbine engine blade using a LPPS unit equipped with a computerized robot. Optimal processing conditions, including spray parameters, the trajectory of the robot, and the synchronized movements between the torch and the blade, have been developed for superior coating properties. Transferred arc treatment, providing a preheating and a cleaning of the substrate surface, enhances the adherence of the coatings to the substrate. The resulting LPPS coatings show dense and uniform characteristics with ideal hardness, and good corrosion resistance to cycle oxidation.
基金Sponsored by the Ministerial Advanced Research Foundation (C2002AA002)
文摘A variable nozzle turbocharger (VNT) was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in which VNT adjustment is carried out through pre-calibrated VNT handling rod position,combined with a closed-loop target boost pressure feedback using proportional-integral-derivative(PID) algorithm.Experimental results showed that the VNT control system presented in this thesis can lead to optimized performance of VNT,increase engine volumetric efficiency over a wide speed range,improve engine dynamic characteristics and upgrade economic performance.
基金This work was co-supported by the Ministry of Science and Technology of China(2017YFC0307603)the China Geological Survey project(DD20190234).
文摘The permeability of a natural gas hydrate reservoir is a critical parameter associated with gas hydrate production.Upon producing gas from a hydrate reservoir via depressurization,the permeability of sediments changes in two ways with hydrate dissociation,increasing with more pore space released from hydrate and decreasing due to pore compression by stronger effective stress related to depressurization.In order to study the evolution of sediment permeability during the production process with the depressurization method,an improved pore network model(PNM)method is developed to establish the permeability change model.In this model,permeability change induced by hydrate dissociation is investigated under hydrate occurrence morphology of pore filling and grain coating.The results obtained show that hydrate occurrence in sediment pore is with significant influence on permeability change.Within a reasonable degree of pore compression in field trial,the effect of pore space release on the reservoir permeability is greater than that of pore compression.The permeability of hydrate containing sediments keeps increasing in the course of gas production,no matter with what hydrate occurrence in sediment pore.
基金This research was financially supported by the National Science and Technology Major Project(2016ZX05034)project of China Gelogical Survey(DD20160181).
文摘In order to evaluate the geological characteristics and gas-bearing factors of Niutitang Formation within the Lower Cambrian of northern Guizhou,the Huangping area located at the southern edge of the ancient uplift belt of Xuefeng Mountain was selected as the target area,and Well Huangdi 1 was drilled for the geological survey of shale gas.Through geological background analysis and well logging and laboratory analysis such as organic geochemical test,gas content analysis,isothermal adsorption,and specific surface area experiments on Well Huangdi 1,the results show that the Niutitang Formation is a deep-water shelf,trough-like folds and thrust fault.The thickness of black shale is 119.95 m,of which carbonaceous shale is 89.6 m.The average value of organic carbon content is 3.55%,kerogen vitrinite reflectance value is 2.37% and kerogen type is sapropel-type.The brittle mineral content is 51%(quartz 38%),clay mineral content is 38.3%.The value of porosity and permeability are 0.5%and 0.0014 mD,which the reservoir of the Niutitang Formation belongs to low permeability with characteristics of ultra-low porosity.The gas content is 0.09‒1.31 m^3/t with a high-value area and a second high-value area.By comparing with the geological parameters of adjacent wells in the adjacent area,the accumulation model of“sediment control zone,Ro control zone,structure controlling reservoir”in the study area is proposed.Therefore,deep-water shelf-slope facies,Ro is between high maturity-early stage of overmaturity and well-preserved zones in the Niutitang Formation in this area are favorable direction for the next step of shale gas exploration.
基金The study associated with this paper was supported by projects of China Geological Survey(DD20190085,DD20160183,1212011120976).
文摘The Sichuan Basin is one of the vital basins in China,boasting abundant hydrocarbon reservoirs.To clarify the intensity of the tectonic stress field of different tectonic episodes since the Mesozoic and to identify the regional dynamic background of different tectonic movements in the Sichuan Basin and its adjacent areas,the characteristics of the acoustic emission in rocks in different strata of these areas were researched in this paper.Meanwhile,the tectonic stress magnitude in these areas since the Mesozoic was restored.The laws state that the tectonic stress varied with depth was revealed,followed by the discussion of the influence of structural stress intensity on structural patterns in different tectonic episodes.These were conducted based on the paleostress measurement by acoustic emission method and the inversion principle of the stress fields in ancient periods and the present,as well as previous research achievements.The results of this paper demonstrate that the third episode of Yanshanian Movement(Yanshanian III)had the maximum activity intensity and tremendously influenced the structural pattern in the study area.The maximum horizontal principal stress of Yanshanian III varied with depth as follows:0.0168 x+37.001(MPa),R^2=0.8891.The regional structural fractures were mainly formed in Yanshanian III in Xujiahe Formation,west Sichuan Basin,of which the maximum paleoprincipal stress ranging from 85.1 MPa to 120.1 MPa.In addition,the law stating the present maximum horizontal principal stress varies with depth was determined to be 0.0159 x+10.221(MPa),R^2=0.7868 in Wuling Mountain area.Meanwhile,it was determined to be 0.0221 x+9.4733(MPa),R^2=0.9121 in the western part of Xuefeng Mountain area and 0.0174 x+10.247(MPa),R^2=0.8064 in the whole study area.These research results will not only provide data for the simulation of stress field,the evaluation of deformation degree,and the prediction of structural fractures,but also offer absolute geological scientific bases for the elevation of favorable shale gas preservation.
基金jointly supported by the Natural Gas Hydrate Exploration and Production Test Project of China Geological Survey (DD20221700)Key-Area Research and Development Program of Guangdong Province (2020B1111030003)Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering G uangdong Laboratory (Guangzhou) (GML2019ZD0504)。
文摘Traditional suction anchor technology is mainly used in the fields of subsea structure bearing foundations,single-point mooring systems and offshore wind power.It is characterized by providing sufficient lateral and vertical bearing capacities and lateral bending moment.The anchor structure of a traditional suction anchor structure is improved with wellhead suction anchor technology,where a central pipe is added as a channel for drilling and completion operations.To solve the technical problems of a low wellhead bearing capacity,shallow built-up depth,and limited application of conductor jetting in the second production test of natural gas hydrates(NGHs)in the South China Sea(SCS),the China Geological Survey(CGS)took the lead in independently designing and manufacturing a wellhead suction anchor,which fulfilled the requirements of the production test.This novel anchor was successfully implemented in the second production test for the first time,providing a stable wellhead foundation for the success of the second production test of NGHs in the SCS.
基金This work was financially supported by the National Natural Science Foundation of China(41802158)projects of China Geological Survey(DD20160183,DD20190085)+2 种基金Major State Research Development Program of China(2016YFC0600202)Fundamental Research Funds for Chinese Academy of Geological Sciences(JYYWF20181201)the CGS-CSC Scholarship Fund(201908575013).
文摘The composition of gas released under vacuum by crushing from the gas shale of Longmaxi Formation in Upper Yangtze Plate,Southern China was systematically investigated in this study.The effect of residual gas release on pore structures was checked using low-pressure nitrogen adsorption techniques.The influence of particle size on the determination of pore structure characteristics was considered.Using the Frenkel-Halsey-Hill method from low-pressure nitrogen adsorption data,the fractal dimensions were identified at relative pressures of 0‒0.5 and 0.5‒1 as D1 and D2,respectively,and the evolution of fractal features related to gas release was also discussed.The results showed that a variety component of residual gas was released from all shale samples,containing hydrocarbon gas of CH4(29.58%‒92.53%),C2H6(0.97%‒2.89%),C3H8(0.01%‒0.65%),and also some non-hydrocarbon gas such as CO2(3.54%‒67.09%)and N2(1.88%‒8.07%).The total yield of residual gas was in a range from 6.1μL/g to 17.0μL/g related to rock weight.The geochemical and mineralogical analysis suggested that the residual gas yield was positively correlated with quartz(R^2=0.5480)content.The residual gas released shale sample has a higher surface area of 17.20‒25.03 m^2/g and the nitrogen adsorption capacity in a range of 27.32‒40.86 ml/g that is relatively higher than the original samples(with 9.22‒16.30 m^2/g and 10.84‒17.55 ml/g).Clearer hysteresis loop was observed for the original shale sample in nitrogen adsorption-desorption isotherms than residual gas released sample.Pore structure analysis showed that the proportions of micro-,meso-and macropores were changed as micropores decreased while meso-and macropores increased.The fractal dimensions D1 were in range from 2.5466 to 2.6117 and D2 from 2.6998 to 2.7119 for the residual gas released shale,which is smaller than the original shale.This factor may indicate that the pore in residual gas released shale was more homogeneous than the original shale.The results indicated that both residual gas and their pore space have few contributions to shale gas production and effective reservoir evaluation.The larger fragments samples of granular rather than powdery smaller than 60 mesh fraction of shale seem to be better for performing effective pore structure analysis to the Longmaxi shale.
基金funded by the projects initiated by the China Geological Survey(DD20190217 and DD20190230)the key special project for introduced talent team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0102)Guangdong Major project of Basic and Applied Basic Research(2020B0301030003).
文摘Various factors controlling the accumulation of natural gas hydrates(NGHs)form various enrichment and accumulation modes through organic combination.This study mainly analyzes the geological and geophysical characteristics of the NGHs occurrence in the uplifts and their slope zones within the deep-water area in the Qiongdongnan(QDN)Basin(also referred to as the study area).Furthermore,it investigates the dominant governing factors and models of NGHs migration and accumulation in the study area.The results are as follows.(1)The uplifts and their slope zones in the study area lie in the dominant pressure-relief direction of fluids in central hydrocarbon-rich sags in the area,which provide sufficient gas sources for the NGHs accumulation and enrichment through pathways such as gas chimneys and faults.(2)The top and flanks of gas chimneys below the bottom simulating reflectors(BSRs)show high-amplitude seismic reflections and pronounced transverse charging of free gas,indicating the occurrence of a large amount of gas accumulation at the heights of the uplifts.(3)Chimneys,faults,and high-porosity and high-permeability strata,which connect the gas hydrate temperature-pressure stability zones(GHSZs)with thermogenic gas and biogenic gas,form the main hydrate migration system.(4)The reservoir system in the study area comprises sedimentary interlayers consisting of mass transport deposits(MTDs)and turbidites.In addition,the reservoir system has developed fissure-and pore-filling types of hydrates in the pathways.The above well-matched controlling factors of hydrate accumulation enable the uplifts and their slope zones in the study area to become the favorable targets of NGHs exploration.
基金This study was funded by Jiangxi Provincial Natural Science Foundation(20202BABL211019)the National Science and Technology Major Project(2016ZX05026007)+2 种基金the National Major Fundamental Research and Development Project(2009CB219400)Open Fund Project of Key Laboratory of Sedimentary Mineralization and Sedimentary Mineral Resources in Shandong Province(DMSM 2019008)National Natural Science Foundation of China(41502081).
文摘North Carnarvon Basin is a gas province with minor oily sweet spots in deepwater area with water depth more than 500 m,which is one of the hot spots of global petroleum exploration for its series of giant hydrocarbon discoveries in recent years.However,the degree of oil and gas exploration in deepwater area is still low,and the conditions for oil and gas accumulation are not clear.Based on the current exploration situation and latest database of fields,applying multidisciplinary analysis of hydrocarbon geology,hydrocarbon accumulation elements and its exploration direction of North Carnarvon Basin in deepwater area are analyzed.The results show that there are three sets of main source rocks in deepwater area of North Carnarvon Basin,which are Triassic marine shale in Locker Formation and delta coal-bearing mudstone with thin carbonaceous mudstone in Mungaroo Formation,Lower–Middle Jurassic paralic carbargilite and coal measure strata in Athol Formation and Murat Formation,Cretaceous delta mudstone in Barrow Group and marine shale in Muderong Formation.Most source rock samples show gas-prone capability.The coarse sandstone of delta facies in Middle–Upper Triassic Mungaroo Formation is the most important reservoir in deepwater area,Lower Cretaceous Barrow Group deep-water gravity flow or underwater fan turbidite sandstone is the secondly main reservoir.Lower Cretaceous marine shale in Muderong Formation is most important regional caprock.Triassic mudstone in Mungaroo Formation is an important interlayer caprock in deepwater area.There are two main reservoir accumulation assemblages in deepwater area,one is Triassic structural-unconformity plane reservoir accumulation assemblage of Locker Formation to Mungaroo Formation,and the other is Lower–Middle Jurassic Athol Formation and Murat Formation–Lower Cretaceous stratigraphic lithology-structural reservoir accumulation assemblage of Barrow Group to Muderong Formation.There are three main control factors of hydrocarbon Accumulation:One is coupling of source and seal control hydrocarbon distribution area,the second is multi-stage large wave dominated deltas dominate accumulation zone,the third is direction of hydrocarbon migration and accumulation in hydrocarbon-rich generation depression was controlled by overpressure.The south of Exmouth platform in deepwater area is adjacent to hydrocarbon rich depression zone,reservoir assemblage is characterized by“near source rocks,excellent reservoir facies,high position and excellent caprocks”,which is the main battlefield of deepwater oil and gas exploration in North Carnarvon Basin at present.There are a lot of fault block traps in the northern structural belt of Exmouth platform,and the favorable sedimentary facies belt at the far end of delta plain in Mungaroo Formation is widely distributed,which is the next favorable exploration zone.The Lower Cretaceous,which is located at the concave edge uplift adjacent to the investigator depression and the Exmouth platform,also has a certain exploration prospect in northwest of deepwater area.
基金the National Natural Science Foundation of China(No:20273043)the Ministry of Education of China for providing financial support for this project
文摘A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted in improved activities of the fresh and aged catalyst by lowering the light-off temperature for methane in natural gas engines exhaust.
基金funded by the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0307)the gas hydrate program initiated by the China Geological Survey(DD20190218)the project of the National Natural Science Foundation of China(11872365).
文摘Natural gas hydrates(NGHs)are a new type of clean energy with great development potential.However,it is urgent to achieve safe and economical NGHs development and utilization.This study established a physical model of the study area using the FLAC^(3D) software based on the key parameters of the NGHs production test area in the South China Sea,including the depressurization method,and mechanical parameters of strata,NGHs occurrence characteristics,and the technological characteristics of horizontal wells.Moreover,this study explored the law of influences of the NGHs dissociation range on the stability of the overburden strata and the casing structure of a horizontal well.The results are as follows.With the dissociation of NGHs,the overburden strata of the NGHs dissociation zone subsided and formed funnelshaped zones and then gradually stabilized.However,the upper interface of the NGHs dissociation zone showed significant redistribution and discontinuity of stress.Specifically,distinct stress concentration and corresponding large deformation occurred in the build-up section of the horizontal well,which was thus prone to suffering shear failure.Moreover,apparent end effects occurred at the end of the horizontal well section and might cause the deformation and failure of the casing structure.Therefore,it is necessary to take measures in the build-up section and at the end of the horizontal section of the horizontal well to prevent damage and ensure the wellbore safety in the long-term NGHs exploitation.