Based on the techniques of X-ray diffraction analysis, identification of the thin sections of core cast, physical analysis and scanning electron microscopy analysis, this paper studied the reservoir characteristics of...Based on the techniques of X-ray diffraction analysis, identification of the thin sections of core cast, physical analysis and scanning electron microscopy analysis, this paper studied the reservoir characteristics of the Carboniferous strata in Donghe well No.1 of Tarim region. The results show that the reservoir lithology is mainly the fine-grained quartz sandstone with ferrocalcite and pyrite, mud cement-based,the permeability concentrated in 5–40 ? 10–3 lm2, a small part of the high permeability up to150–327 ? 10à3lm2and porosity ranged from 10% to 20%. The most part of the reservoirs is low permeability with a small part of the layer in moderate-high permeability. The types of reservoir space include intergranular pores, intra particle-molding pores, micro-pores and cracks, which mainly are intergranular pores with the pore diameter of 15–200 lm, 95.5 lm on average. And the types of the throats are complex with the main type of constricted throats in this area and large contribution to the permeability.展开更多
Based on core, thin-section, scanning electron microscopy(SEM) and well logging data, the characteristics of the parametamorphic rock reservoirs in the Pingxi area were analyzed by means of whole rock X-ray diffractio...Based on core, thin-section, scanning electron microscopy(SEM) and well logging data, the characteristics of the parametamorphic rock reservoirs in the Pingxi area were analyzed by means of whole rock X-ray diffraction and micron CT scanning. The parametamorphic rock reservoirs mainly had three types of rocks: slate, crystalline limestone and calc-schist; the original rocks were Ordovician-Silurian marine clastic and carbonate rocks. The three types of parametamorphic rock reservoirs developed three types and six sub-types of reservoir space. The first type of reservoir space was fractures, including structural, weathered and dissolution fractures; the second type was dissolved porosities, including dissolved pores and caves; the third type was nano-sized intercrystalline porosities. The three types of parametamorphic rock reservoirs were different widely in the quantity, volume and radius of pore-throats, and were strongly affected by the type and development degree of fractures. The parametamorphic rock reservoirs were formed by metamorphism, weathering, structural fragmentation and dissolution. Metamorphism reformed the parametamorphic rock reservoirs significantly, breaking the traditional constraint of finding weathering crust at top. The parametamorphic rock reservoirs experienced five formation stages, and their distribution was controlled by rock type, metamorphic degree, ancient geomorphology, and weathering intensity.展开更多
With the aim of better understanding the tight gas reservoirs in the Zizhou area of east Ordos Basin,a total of 222 samples were collected from 50 wells for a series of experiments.In this study,three pore-throat comb...With the aim of better understanding the tight gas reservoirs in the Zizhou area of east Ordos Basin,a total of 222 samples were collected from 50 wells for a series of experiments.In this study,three pore-throat combination types in sandstones were revealed and confirmed to play a controlling role in the distribution of throat size and the characteristics of gas-water relative permeability.The type-I sandstones are dominated by intercrystalline micropores connected by cluster throats,of which the distribution curves of throat size are narrow and have a strong single peak(peak ratio>30%).The pores in the type-II sandstones dominantly consist of secondary dissolution pores and intercrystalline micropores,and throats mainly occur as slice-shaped throats along cleavages between rigid grain margins and cluster throats in clay cement.The distribution curves of throat size for the type-II sandstones show a bimodal distribution with a substantial low-value region between the peaks(peak ratio<15%).Primary intergranular pores and secondary intergranular pores are mainly found in type-III samples,which are connected by various throats.The throat size distribution curves of type-III sandstones show a nearly normal distribution with low kurtosis(peak ratio<10%),and the micro-scale throat radii(>0.5μm)constitute a large proportion.From type-I to type-III sandstones,the irreducible water saturation(Swo)decreased;furthermore,the slope of the curves of Krw/Krg in two-phase saturation zone decreased and the two-phase saturation zone increased,indicating that the gas relative flow ability increased.Variations of the permeability exist in sandstones with different porethroat combination types,which indicate the type-III sandstones are better reservoirs,followed by type-II sandstones and type-I sandstones.As an important factor affecting the reservoir quality,the pore-throat combination type in sandstones is the cumulative expression of lithology and diagenetic modifications with strong heterogeneity.展开更多
A straightforward technique has been developed to quickly determine the wall contour of super/hypersonic nozzles working at multiply Mach number which share a common throat section.Mach number distribution along the c...A straightforward technique has been developed to quickly determine the wall contour of super/hypersonic nozzles working at multiply Mach number which share a common throat section.Mach number distribution along the centerline of the nozzle is specified in advance and divided into two sections,both of which are described by the b-spline function.The first section is shared by different exit Mach number nozzles.The nozzle contour is determined by the method of characteristics plus boundary layer correction.An example of this design method is employed to illustrate the technique with a computational fluid dynamics calculation.The simulation results indicate that desired Mach numbers are obtained at the nozzle exit,and the good flow quality is attained for different nozzles within δMa/Ma<±0.56% in the flow core region.This technique improves the design precision of the converging-diverging nozzle,cancels waves completely,and achieves nozzles with multiple Mach number exiting which share a common throat section.展开更多
基金financially supported by the National Major Special Projects of China (No. 2011ZX05005-002-009HZ)the Natural Science Foundation Project of CQ CSTC of China (No. cstc2012jjA90009)+1 种基金the Research Foundation of Chongqing University of Science & Technology of China (Nos. CK20111312, CK2013Z04)the Program of Educational Reform of Chongqing University of Science & Technology of China (No. 201424).
文摘Based on the techniques of X-ray diffraction analysis, identification of the thin sections of core cast, physical analysis and scanning electron microscopy analysis, this paper studied the reservoir characteristics of the Carboniferous strata in Donghe well No.1 of Tarim region. The results show that the reservoir lithology is mainly the fine-grained quartz sandstone with ferrocalcite and pyrite, mud cement-based,the permeability concentrated in 5–40 ? 10–3 lm2, a small part of the high permeability up to150–327 ? 10à3lm2and porosity ranged from 10% to 20%. The most part of the reservoirs is low permeability with a small part of the layer in moderate-high permeability. The types of reservoir space include intergranular pores, intra particle-molding pores, micro-pores and cracks, which mainly are intergranular pores with the pore diameter of 15–200 lm, 95.5 lm on average. And the types of the throats are complex with the main type of constricted throats in this area and large contribution to the permeability.
基金Supported by the China National Science and Technology Major Project(2017ZX05001-002)
文摘Based on core, thin-section, scanning electron microscopy(SEM) and well logging data, the characteristics of the parametamorphic rock reservoirs in the Pingxi area were analyzed by means of whole rock X-ray diffraction and micron CT scanning. The parametamorphic rock reservoirs mainly had three types of rocks: slate, crystalline limestone and calc-schist; the original rocks were Ordovician-Silurian marine clastic and carbonate rocks. The three types of parametamorphic rock reservoirs developed three types and six sub-types of reservoir space. The first type of reservoir space was fractures, including structural, weathered and dissolution fractures; the second type was dissolved porosities, including dissolved pores and caves; the third type was nano-sized intercrystalline porosities. The three types of parametamorphic rock reservoirs were different widely in the quantity, volume and radius of pore-throats, and were strongly affected by the type and development degree of fractures. The parametamorphic rock reservoirs were formed by metamorphism, weathering, structural fragmentation and dissolution. Metamorphism reformed the parametamorphic rock reservoirs significantly, breaking the traditional constraint of finding weathering crust at top. The parametamorphic rock reservoirs experienced five formation stages, and their distribution was controlled by rock type, metamorphic degree, ancient geomorphology, and weathering intensity.
基金supported by the Natural Science Foundation of China (grant No. 41772130)
文摘With the aim of better understanding the tight gas reservoirs in the Zizhou area of east Ordos Basin,a total of 222 samples were collected from 50 wells for a series of experiments.In this study,three pore-throat combination types in sandstones were revealed and confirmed to play a controlling role in the distribution of throat size and the characteristics of gas-water relative permeability.The type-I sandstones are dominated by intercrystalline micropores connected by cluster throats,of which the distribution curves of throat size are narrow and have a strong single peak(peak ratio>30%).The pores in the type-II sandstones dominantly consist of secondary dissolution pores and intercrystalline micropores,and throats mainly occur as slice-shaped throats along cleavages between rigid grain margins and cluster throats in clay cement.The distribution curves of throat size for the type-II sandstones show a bimodal distribution with a substantial low-value region between the peaks(peak ratio<15%).Primary intergranular pores and secondary intergranular pores are mainly found in type-III samples,which are connected by various throats.The throat size distribution curves of type-III sandstones show a nearly normal distribution with low kurtosis(peak ratio<10%),and the micro-scale throat radii(>0.5μm)constitute a large proportion.From type-I to type-III sandstones,the irreducible water saturation(Swo)decreased;furthermore,the slope of the curves of Krw/Krg in two-phase saturation zone decreased and the two-phase saturation zone increased,indicating that the gas relative flow ability increased.Variations of the permeability exist in sandstones with different porethroat combination types,which indicate the type-III sandstones are better reservoirs,followed by type-II sandstones and type-I sandstones.As an important factor affecting the reservoir quality,the pore-throat combination type in sandstones is the cumulative expression of lithology and diagenetic modifications with strong heterogeneity.
基金Project(11072264) supported by the National Natural Science Foundation of China
文摘A straightforward technique has been developed to quickly determine the wall contour of super/hypersonic nozzles working at multiply Mach number which share a common throat section.Mach number distribution along the centerline of the nozzle is specified in advance and divided into two sections,both of which are described by the b-spline function.The first section is shared by different exit Mach number nozzles.The nozzle contour is determined by the method of characteristics plus boundary layer correction.An example of this design method is employed to illustrate the technique with a computational fluid dynamics calculation.The simulation results indicate that desired Mach numbers are obtained at the nozzle exit,and the good flow quality is attained for different nozzles within δMa/Ma<±0.56% in the flow core region.This technique improves the design precision of the converging-diverging nozzle,cancels waves completely,and achieves nozzles with multiple Mach number exiting which share a common throat section.
