The shale oil reservoir within the Yanchang Formations of Ordos Basin harbors substantial oil and gas resources and has recently emerged as the primary focus of unconventional oil and gas exploration and development.D...The shale oil reservoir within the Yanchang Formations of Ordos Basin harbors substantial oil and gas resources and has recently emerged as the primary focus of unconventional oil and gas exploration and development.Due to its complex pore and throat structure,pronounced heterogeneity,and tight reservoir characteristics,the techniques for conventional oil and gas exploration and production face challenges in comprehensive implementation,also indicating that as a vital parameter for evaluating the physical properties of a reservoir,permeability cannot be effectively estimated.This study selects 21 tight sandstone samples from the Q area within the shale oil formations of Ordos Basin.We systematically conduct the experiments to measure porosity,permeability,ultrasonic wave velocities,and resistivity at varying confining pressures.Results reveal that these measurements exhibit nonlinear changes in response to effective pressure.By using these experimental data and effective medium model,empirical relationships between P-and S-wave velocities,permeability and resistivity and effective pressure are established at logging and seismic scales.Furthermore,relationships between P-wave impedance and permeability,and resistivity and permeability are determined.A comparison between the predicted permeability and logging data demonstrates that the impedance–permeability relationship yields better results in contrast to those of resistivity–permeability relationship.These relationships are further applied to the seismic interpretation of shale oil reservoir in the target layer,enabling the permeability profile predictions based on inverse P-wave impedance.The predicted results are evaluated with actual production data,revealing a better agreement between predicted results and logging data and productivity.展开更多
To simultaneously take into account the Biot-flow mechanism, the squirt-flow mechanism, and the frame-viscoelasticity mechanism, a generalized viscoelastic BISQ (Biot/squirt) model is developed for wave propagation ...To simultaneously take into account the Biot-flow mechanism, the squirt-flow mechanism, and the frame-viscoelasticity mechanism, a generalized viscoelastic BISQ (Biot/squirt) model is developed for wave propagation in clay-bearing sandstones based on Dvorkin's elastic BISQ model. The present model is extended to a wide range of permeabilities (k 〉 0.05 mD) by introducing a dimensionless correction factor for viscoelastic parameters, defined as a function of the permeability and the clay content. We describe the frame's stress-strain relationship of the clay-bearing sandstones by the differential constitutive equations of generalized viscoelasticity and then derive the viscoelastic-wave dynamic equations. With the assumption of a plane-wave solution, we finally yield the phase velocities and the attenuation coefficients by solving the dynamic wave equations in the frequency and wave number domain. The comparison of numerical results and experimental data shows that the generalized viscoelastic BISQ model is applicable for modeling the wave propagation in most of the sandstones mainly bearing kaolinite clay.展开更多
Peltophorum dubium seeds provided by Anhembi, SP were scarified in 98% H2SO4 for 15 min to overcome mechani-cal dormancy. Seeds were primed in solutions of 0.2% Captan at 10 C and 27C, PEG 6000 -1.0 MPa at 10C and 27...Peltophorum dubium seeds provided by Anhembi, SP were scarified in 98% H2SO4 for 15 min to overcome mechani-cal dormancy. Seeds were primed in solutions of 0.2% Captan at 10 C and 27C, PEG 6000 -1.0 MPa at 10C and 27C, 0.5 mol KNO3, 0.75 Mol KNO3, 1.0 Mol KNO3. Eight treatments including the primed seeds and nonprimed seeds, five replicates with 100 seeds for each treatment, were set to 15-cm-Petri dish with double filter paper moistened with testing solution PEG in refrigerator at 27C. For the experiments of all the groups, osmotic potential were 0.0, -0.2, -0.4, -0.6, -0.8, -1.0, -1.2, and -1.4 MPa. P. dubium seeds were also set to water stress experiment in rolled paper with PEG solutions from 0.0 to -1.0 M Pa. Germination percentage decreased with the increase of PEG concentration. Control group had a better germination percentage than other groups. Germination hardly occurred in PEG -1.4 MPa.展开更多
[ Objective] The purpose was to discuss drought resistance mechanism of Chenopodium album L. and supply theoretical basis and practical guidance for artificial cultivation and popularization of C. album. [ Method] C. ...[ Objective] The purpose was to discuss drought resistance mechanism of Chenopodium album L. and supply theoretical basis and practical guidance for artificial cultivation and popularization of C. album. [ Method] C. album seedlings grown to 6th leaf stage were conducted osmotic stress treatment with PEG6000 osmotic whose concentration was set up as 0, 5%, 10% and 20% and the various physiological indices of the 3rd -5th function leaves in upper plant were determined after being treated for 0, 1,3, 5, 7 and 9 d. [ Result] Under osmotic stress with 5% PGE, the relative water content (RWC) of C. album reduced less. Under osmotic stress with 10%, the RWC in seedling leaves of C. album decreased to 62% on the fifth day and the leaves began to wither. Under osmotic stress with 20%, the RWC in seedling leaves of C. album decreased to 61.9% on the third day and the leaves appeared withering, and the RWC decreased to 48.6% on the 7th day and the leaves were dry and yellow. Proline contents in seedling leaves of C. album under osmotic stress with 5%, 10% and 20% PEG were 7.64, 10.9 and 29.4 times of CK on the 7th day. [ Conclusion] C. album hed some adaptability to moderate osmotic stress, but the PEG osmotic stress with high concentration and long time might lead to severe damage on C. album.展开更多
近年来,经皮给药系统(transdermal drug delivery systems,TDOS)以其独特的优势成为医药领域中重要的研究和开发内容。TDDS具有以下特点:全身作用的药物经皮给药可以克服药物的肝脏首过效应,减少药物对胃肠道的刺激,有效解决药...近年来,经皮给药系统(transdermal drug delivery systems,TDOS)以其独特的优势成为医药领域中重要的研究和开发内容。TDDS具有以下特点:全身作用的药物经皮给药可以克服药物的肝脏首过效应,减少药物对胃肠道的刺激,有效解决药物在体内易失活导致生物利用度低及半衰期短等问题;而对于局部作用的药物,经皮给药则可提高局部的药物浓度,增强疗效,降低全身的药物不良反应;能长期维持稳定的给药速率和血药浓度,降低药物的毒副作用。展开更多
Convection-enhanced delivery (CED) is a promising technique leveraging pressure-driven flow to increase penetration of infused drugs into interstitial spaces. We have developed a fiberoptic microneedle device for in...Convection-enhanced delivery (CED) is a promising technique leveraging pressure-driven flow to increase penetration of infused drugs into interstitial spaces. We have developed a fiberoptic microneedle device for inducing local sub-lethal hyperthermia to further improve CED drug distribution volumes, and this study seeks to quantitatively characterize this approach in agarose tissue phantoms. Infusions of dye were conducted in 0.6% (w/w) agarose tissue phantoms with isothermal conditions at 15 ℃, 20℃, 25 ℃, and 30 ℃. Infusion metrics were quantified using a custom shadowgraphy setup and image- processing algorithm. These data were used to build an empirical predictive temporal model of distribution volume as a function of phantom temperature. A second set of proof- of-concept experiments was conducted to evaluate a novel fiberoptic device capable of generating local photothermal heating during fluid infusion. The isothermal infusions showed a positive correlation between temperature and distribution volume, with the volume at 30℃ showing a 7-fold increase at 100 min over the 15 ℃ isothermal case. Infusions during photothermal heating (1064 nm at 500 mW) showed a similar effect with a 3.5-fold increase at 4 h over the control (0 mW). These results and analyses serve to provide insight into and characterization of heat-mediated enhancement of volumetric dispersal.展开更多
The efficiency of advanced membranes towards removal of general and specific microbes from wastewater was investigated. The treatment included a subsequent system of activated sludge, ultrafiltration (hollow fibre me...The efficiency of advanced membranes towards removal of general and specific microbes from wastewater was investigated. The treatment included a subsequent system of activated sludge, ultrafiltration (hollow fibre membranes with 100 kDa cut-off, and spiral wound membranes with 20 kDa cut-off), and RO (reverse osmosis). The removal evaluation of screened microbes present in treated wastewater showed that hollow fibre membrane rejected only 1 log (90% rejection) of the TPC (total microbial count), TC (total coliforms), and FC (faecal coliforms). A higher effectiveness was observed with spiral wound, removing 2-3 logs (99%-99.9%) of TPC and complete rejection of TC and FC. The RO system was successful in total rejection of all received bacteria. The removal evaluation of inoculated specific types of bacteria showed that the hollow membranes removed 2 logs (99%) of inoculated E. coli (10^7-10^8 cfu/mL inoculum), 2-3 logs (99%-99.9%) of Enterococus spp. (10^7-10^10 cfu/mL inoculum), 1-2 logs (90%-99%) of Salmonella (10^8-10^10 cfu/mL inoculum) and 1-2 logs (90%-99%) of Shigella (10^5-10^6 cfu/mL inoculum). The spiral wound was significantly efficient in rejecting further 3 logs of E. coil, 5 logs of Enterococus spp., 4 logs of Salmonella, and a complete rejection of all received bacteria was accomplished by RO membrane. The results indicate that Gram positive bacteria were removed much more efficiently compared to the Gram negative ones, the rationale behind such behaviour is based on cell walls elasticity.展开更多
Measurements of dielectric parameters followed by permeability tests are performed on soil samples of infiltration basin. The dielectric parameters are obtained by TDR (time domain reflectrometry) measurements from ...Measurements of dielectric parameters followed by permeability tests are performed on soil samples of infiltration basin. The dielectric parameters are obtained by TDR (time domain reflectrometry) measurements from which it is found that the measurement of the permittivity, the electrical conductivity and the relaxation time of compacted soil allows the mapping of the values of the coefficient of permeability at the surface of an infiltration basin. With the distribution of the coefficient of permeability, the areas of water stagnation can be detected before the basin filling. The study proves that the TDR measurements for the detection of these zones can be used for the management of infiltration basins for sustainable working and their remediation can be undertaken before the rainy seasons.展开更多
In order to solve the problem of experimental research on the penetration process of projectile into anchored rock mass, we derived the essential similarity conditions for the physical simulation experi- ment accordin...In order to solve the problem of experimental research on the penetration process of projectile into anchored rock mass, we derived the essential similarity conditions for the physical simulation experi- ment according to the similarity theory, carried out the experiment on the penetration process of a kind of penetrating bomb into the anchored rock mass of type III, and compared the experimental results with the values computed by the professional Young's empirical formula. The test results show that the phys- ical simulation experiment can represent the actual penetration process of projectile into anchored rock mass. The research method proposed in this paper provides technical support for the experimental research on the design and reconstruction of underground protection works.展开更多
Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transforma...Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transformation processes. The structure of the breakwaters can be used as coastal protection system by reducing the amount of incoming wave energy. Effect of slope, core permeability, water depth and incident wave characteristics on the stability was also studied. The breakwater model consisted of a core and two armour layers attacked by irregular waves. This paper discusses and compares the test results with the existing design equations. In general, the existing design equations do not seem to predict the wave transmission and reflection accurately for the range of test data. In the range of variable tested, it was observed that the water depth, crest width and wave period have a significant influence on wave transmission process. Further, results show strong influence of the water depth and wave period on the wave reflection process. The structural stability of low crested breakwaters is very much affected by the water depth and wave period.展开更多
This discussion paper is an attempt to consider new ideas about the nature of explosive phenomena of the meteorite bodies in the Earth's atmosphere. Authors attract approaches, based on the concepts of physics of com...This discussion paper is an attempt to consider new ideas about the nature of explosive phenomena of the meteorite bodies in the Earth's atmosphere. Authors attract approaches, based on the concepts of physics of combustion, explosion and detonation in order to explain the explosive collapse of the meteorite. Authors believe that the meteorite explosion may be the result of gas-detonation mechanism of overheated meteoric bodies explosive boiling-up (the "vapor explosion"), accompanied by the formation of a supersonic front of shock wave. The considered hypothesis regarding the role of the "vapor explosion" in geological disasters can be used to explain the mechanisms of explosive phenomena in Volcanology: (1) With respect to the description of nature of phreatic eruptions; (2) for interpretation of dynamic regularities of the volcano crater opening and the subsequent shock-wave emission of steam-gas "fountain" to a height of several kilometers with fragments of magma and rocks as a result of the "vapor explosion" of overheated magma mass under the dome of the volcano.展开更多
Rate transient method is a recently-developed performance analysis tool specially designed for low-permeability or tight gas reservoirs. This method, theoretically based on pressure transient analysis, integrates mate...Rate transient method is a recently-developed performance analysis tool specially designed for low-permeability or tight gas reservoirs. This method, theoretically based on pressure transient analysis, integrates material balance principle and the concept of material balance pseudo-time proposed by Blansingame. With daily production data of gas well, it could be used to calculate OGIP, current formation pressure, permeability, skin factor, to identify complex geologic boundaries, to determine whether drainage boundary has been reached, to calculate drainage area and drainage radius for single well and to predict performance. It has been extensively employed in more than ten low-permeability gas fields. It proves that most problems in performance analysis for low permeability gas reservoirs could be solved by this method. Field practices show great economical benefits could be achieved by employing this method in gas field development.展开更多
基金supports from the National Natural Science Foundation of China(42104110,41974123,42174161,and 12334019)the Natural Science Foundation of Jiangsu Province(BK20210379,BK20200021)+1 种基金the Postdoctoral Science Foundation of China(2022M720989)the Fundamental Research Funds for the Central Universities(B210201032).
文摘The shale oil reservoir within the Yanchang Formations of Ordos Basin harbors substantial oil and gas resources and has recently emerged as the primary focus of unconventional oil and gas exploration and development.Due to its complex pore and throat structure,pronounced heterogeneity,and tight reservoir characteristics,the techniques for conventional oil and gas exploration and production face challenges in comprehensive implementation,also indicating that as a vital parameter for evaluating the physical properties of a reservoir,permeability cannot be effectively estimated.This study selects 21 tight sandstone samples from the Q area within the shale oil formations of Ordos Basin.We systematically conduct the experiments to measure porosity,permeability,ultrasonic wave velocities,and resistivity at varying confining pressures.Results reveal that these measurements exhibit nonlinear changes in response to effective pressure.By using these experimental data and effective medium model,empirical relationships between P-and S-wave velocities,permeability and resistivity and effective pressure are established at logging and seismic scales.Furthermore,relationships between P-wave impedance and permeability,and resistivity and permeability are determined.A comparison between the predicted permeability and logging data demonstrates that the impedance–permeability relationship yields better results in contrast to those of resistivity–permeability relationship.These relationships are further applied to the seismic interpretation of shale oil reservoir in the target layer,enabling the permeability profile predictions based on inverse P-wave impedance.The predicted results are evaluated with actual production data,revealing a better agreement between predicted results and logging data and productivity.
基金supported by the National Science Fund for Distinguished Young Scholars of China (Grant No. 40725012)the National Hi-tech Research and Development Program of China(863 Program) (Grant No. 2006AA06Z240)the National Basic Research Program of China (973 program)(Grant No. 2007CB209505).
文摘To simultaneously take into account the Biot-flow mechanism, the squirt-flow mechanism, and the frame-viscoelasticity mechanism, a generalized viscoelastic BISQ (Biot/squirt) model is developed for wave propagation in clay-bearing sandstones based on Dvorkin's elastic BISQ model. The present model is extended to a wide range of permeabilities (k 〉 0.05 mD) by introducing a dimensionless correction factor for viscoelastic parameters, defined as a function of the permeability and the clay content. We describe the frame's stress-strain relationship of the clay-bearing sandstones by the differential constitutive equations of generalized viscoelasticity and then derive the viscoelastic-wave dynamic equations. With the assumption of a plane-wave solution, we finally yield the phase velocities and the attenuation coefficients by solving the dynamic wave equations in the frequency and wave number domain. The comparison of numerical results and experimental data shows that the generalized viscoelastic BISQ model is applicable for modeling the wave propagation in most of the sandstones mainly bearing kaolinite clay.
基金This work is Supported by CAPES Brazil. Open research laboratory of forest plant ecology NEFU. The State's tenth five-year "211 Project"-supported key academic discipline program of ECNU。
文摘Peltophorum dubium seeds provided by Anhembi, SP were scarified in 98% H2SO4 for 15 min to overcome mechani-cal dormancy. Seeds were primed in solutions of 0.2% Captan at 10 C and 27C, PEG 6000 -1.0 MPa at 10C and 27C, 0.5 mol KNO3, 0.75 Mol KNO3, 1.0 Mol KNO3. Eight treatments including the primed seeds and nonprimed seeds, five replicates with 100 seeds for each treatment, were set to 15-cm-Petri dish with double filter paper moistened with testing solution PEG in refrigerator at 27C. For the experiments of all the groups, osmotic potential were 0.0, -0.2, -0.4, -0.6, -0.8, -1.0, -1.2, and -1.4 MPa. P. dubium seeds were also set to water stress experiment in rolled paper with PEG solutions from 0.0 to -1.0 M Pa. Germination percentage decreased with the increase of PEG concentration. Control group had a better germination percentage than other groups. Germination hardly occurred in PEG -1.4 MPa.
基金Supported by the Natural Science Foundation of Education Department of Jiangsu Province(02KJD18007)the Key Laboratory Program of Bio-re-sources of Jiangsu Province(KJS03042)the Key Program of Natural Science Foundation of Xuzhou Normal University(06XLA11)~~
文摘[ Objective] The purpose was to discuss drought resistance mechanism of Chenopodium album L. and supply theoretical basis and practical guidance for artificial cultivation and popularization of C. album. [ Method] C. album seedlings grown to 6th leaf stage were conducted osmotic stress treatment with PEG6000 osmotic whose concentration was set up as 0, 5%, 10% and 20% and the various physiological indices of the 3rd -5th function leaves in upper plant were determined after being treated for 0, 1,3, 5, 7 and 9 d. [ Result] Under osmotic stress with 5% PGE, the relative water content (RWC) of C. album reduced less. Under osmotic stress with 10%, the RWC in seedling leaves of C. album decreased to 62% on the fifth day and the leaves began to wither. Under osmotic stress with 20%, the RWC in seedling leaves of C. album decreased to 61.9% on the third day and the leaves appeared withering, and the RWC decreased to 48.6% on the 7th day and the leaves were dry and yellow. Proline contents in seedling leaves of C. album under osmotic stress with 5%, 10% and 20% PEG were 7.64, 10.9 and 29.4 times of CK on the 7th day. [ Conclusion] C. album hed some adaptability to moderate osmotic stress, but the PEG osmotic stress with high concentration and long time might lead to severe damage on C. album.
文摘近年来,经皮给药系统(transdermal drug delivery systems,TDOS)以其独特的优势成为医药领域中重要的研究和开发内容。TDDS具有以下特点:全身作用的药物经皮给药可以克服药物的肝脏首过效应,减少药物对胃肠道的刺激,有效解决药物在体内易失活导致生物利用度低及半衰期短等问题;而对于局部作用的药物,经皮给药则可提高局部的药物浓度,增强疗效,降低全身的药物不良反应;能长期维持稳定的给药速率和血药浓度,降低药物的毒副作用。
基金the Coulter Foundation and NIH (NIH/NCI 1R21CA156078) for their funding of this project
文摘Convection-enhanced delivery (CED) is a promising technique leveraging pressure-driven flow to increase penetration of infused drugs into interstitial spaces. We have developed a fiberoptic microneedle device for inducing local sub-lethal hyperthermia to further improve CED drug distribution volumes, and this study seeks to quantitatively characterize this approach in agarose tissue phantoms. Infusions of dye were conducted in 0.6% (w/w) agarose tissue phantoms with isothermal conditions at 15 ℃, 20℃, 25 ℃, and 30 ℃. Infusion metrics were quantified using a custom shadowgraphy setup and image- processing algorithm. These data were used to build an empirical predictive temporal model of distribution volume as a function of phantom temperature. A second set of proof- of-concept experiments was conducted to evaluate a novel fiberoptic device capable of generating local photothermal heating during fluid infusion. The isothermal infusions showed a positive correlation between temperature and distribution volume, with the volume at 30℃ showing a 7-fold increase at 100 min over the 15 ℃ isothermal case. Infusions during photothermal heating (1064 nm at 500 mW) showed a similar effect with a 3.5-fold increase at 4 h over the control (0 mW). These results and analyses serve to provide insight into and characterization of heat-mediated enhancement of volumetric dispersal.
文摘The efficiency of advanced membranes towards removal of general and specific microbes from wastewater was investigated. The treatment included a subsequent system of activated sludge, ultrafiltration (hollow fibre membranes with 100 kDa cut-off, and spiral wound membranes with 20 kDa cut-off), and RO (reverse osmosis). The removal evaluation of screened microbes present in treated wastewater showed that hollow fibre membrane rejected only 1 log (90% rejection) of the TPC (total microbial count), TC (total coliforms), and FC (faecal coliforms). A higher effectiveness was observed with spiral wound, removing 2-3 logs (99%-99.9%) of TPC and complete rejection of TC and FC. The RO system was successful in total rejection of all received bacteria. The removal evaluation of inoculated specific types of bacteria showed that the hollow membranes removed 2 logs (99%) of inoculated E. coli (10^7-10^8 cfu/mL inoculum), 2-3 logs (99%-99.9%) of Enterococus spp. (10^7-10^10 cfu/mL inoculum), 1-2 logs (90%-99%) of Salmonella (10^8-10^10 cfu/mL inoculum) and 1-2 logs (90%-99%) of Shigella (10^5-10^6 cfu/mL inoculum). The spiral wound was significantly efficient in rejecting further 3 logs of E. coil, 5 logs of Enterococus spp., 4 logs of Salmonella, and a complete rejection of all received bacteria was accomplished by RO membrane. The results indicate that Gram positive bacteria were removed much more efficiently compared to the Gram negative ones, the rationale behind such behaviour is based on cell walls elasticity.
文摘Measurements of dielectric parameters followed by permeability tests are performed on soil samples of infiltration basin. The dielectric parameters are obtained by TDR (time domain reflectrometry) measurements from which it is found that the measurement of the permittivity, the electrical conductivity and the relaxation time of compacted soil allows the mapping of the values of the coefficient of permeability at the surface of an infiltration basin. With the distribution of the coefficient of permeability, the areas of water stagnation can be detected before the basin filling. The study proves that the TDR measurements for the detection of these zones can be used for the management of infiltration basins for sustainable working and their remediation can be undertaken before the rainy seasons.
文摘In order to solve the problem of experimental research on the penetration process of projectile into anchored rock mass, we derived the essential similarity conditions for the physical simulation experi- ment according to the similarity theory, carried out the experiment on the penetration process of a kind of penetrating bomb into the anchored rock mass of type III, and compared the experimental results with the values computed by the professional Young's empirical formula. The test results show that the phys- ical simulation experiment can represent the actual penetration process of projectile into anchored rock mass. The research method proposed in this paper provides technical support for the experimental research on the design and reconstruction of underground protection works.
文摘Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transformation processes. The structure of the breakwaters can be used as coastal protection system by reducing the amount of incoming wave energy. Effect of slope, core permeability, water depth and incident wave characteristics on the stability was also studied. The breakwater model consisted of a core and two armour layers attacked by irregular waves. This paper discusses and compares the test results with the existing design equations. In general, the existing design equations do not seem to predict the wave transmission and reflection accurately for the range of test data. In the range of variable tested, it was observed that the water depth, crest width and wave period have a significant influence on wave transmission process. Further, results show strong influence of the water depth and wave period on the wave reflection process. The structural stability of low crested breakwaters is very much affected by the water depth and wave period.
文摘This discussion paper is an attempt to consider new ideas about the nature of explosive phenomena of the meteorite bodies in the Earth's atmosphere. Authors attract approaches, based on the concepts of physics of combustion, explosion and detonation in order to explain the explosive collapse of the meteorite. Authors believe that the meteorite explosion may be the result of gas-detonation mechanism of overheated meteoric bodies explosive boiling-up (the "vapor explosion"), accompanied by the formation of a supersonic front of shock wave. The considered hypothesis regarding the role of the "vapor explosion" in geological disasters can be used to explain the mechanisms of explosive phenomena in Volcanology: (1) With respect to the description of nature of phreatic eruptions; (2) for interpretation of dynamic regularities of the volcano crater opening and the subsequent shock-wave emission of steam-gas "fountain" to a height of several kilometers with fragments of magma and rocks as a result of the "vapor explosion" of overheated magma mass under the dome of the volcano.
文摘Rate transient method is a recently-developed performance analysis tool specially designed for low-permeability or tight gas reservoirs. This method, theoretically based on pressure transient analysis, integrates material balance principle and the concept of material balance pseudo-time proposed by Blansingame. With daily production data of gas well, it could be used to calculate OGIP, current formation pressure, permeability, skin factor, to identify complex geologic boundaries, to determine whether drainage boundary has been reached, to calculate drainage area and drainage radius for single well and to predict performance. It has been extensively employed in more than ten low-permeability gas fields. It proves that most problems in performance analysis for low permeability gas reservoirs could be solved by this method. Field practices show great economical benefits could be achieved by employing this method in gas field development.