The organic matter degradation process during anaerobic co-digestion of municipal biomass waste （MBW） and waste-activated sludge （WAS） under different organic loading rates （OLRs） was investigated in bench-scale...The organic matter degradation process during anaerobic co-digestion of municipal biomass waste （MBW） and waste-activated sludge （WAS） under different organic loading rates （OLRs） was investigated in bench-scale and pilot-scale semi-continuous stirred tank reactors. To better understand the degradation process of MBW and WAS co-digestion and provide theoretical guidance for engineering application, anaerobic digestion model No. 1 was revised for the co-digestion of MBW and WAS. The results showed that the degradation of organic matter could be characterized into three different fractions, including readily hydrolyzable organics, easily degradable particulate organics, and recalcitrant particle organics. Hydrolysis was the rate-limiting step under lower OLRs, and methanogenesisis was the rate-limiting step for an OLR of 8.0 kg volatile solid （VS）/（m^3·day）. The hydrolytic parameters of carbohydrate, protein, and lipids were 0.104, 0.083, and 0.084 kg chemical oxygen demand （COD）/（kg COD·hr）, respectively, and the reaction rate parameters of lipid fermentation were 1 and 1.25 kg COD/（kg COD.hr） for OLRs of 4.0 and 6.0 kg VS/（m^3·day）. A revised model was used to simulate methane yield, and the results fit well with the experimental data. Material balance data were acquired based on the revised model, which showed that 58.50% of total COD was converted to methane.展开更多
Carbonate gas reservoirs are often characterized by strong heterogeneity,complex inter-well connectivity,extensive edge or bottom water,and unbalanced production,challenges that are also common in many heterogeneous g...Carbonate gas reservoirs are often characterized by strong heterogeneity,complex inter-well connectivity,extensive edge or bottom water,and unbalanced production,challenges that are also common in many heterogeneous gas reservoirs with intricate storage and flow behavior.To address these issues within a unified,data-driven framework,this study develops a multi-block material balance model that accounts for inter-block flow and aquifer influx,and is applicable to a wide range of reservoir types.The model incorporates inter-well and well-group conductive connectivity together with pseudo–steady-state aquifer support.The governing equations are solved using a Newton–Raphson scheme,while particle swarm optimization is employed to estimate formation pressures,inter-well connectivity,and effective aquifer volumes.An unbalanced exploitation factor,UEF,is introduced to quantify production imbalance and to guide development optimization.Validation using a synthetic reservoir model demonstrates that the approach accurately reproduces pressure evolution,crossflow behavior,and water influx.Application to a representative case(the Longwangmiao)field further confirms its robustness under highly heterogeneous conditions,achieving a 12.9%reduction in UEF through optimized production allocation.展开更多
As the main unconventional natural gas reservoirs,shale gas reservoirs and coalbed methane(CBM)reservoirs belong to adsorptive gas reservoirs,i.e.,gas reservoirs containing adsorbed gas.Shale gas and CBM reservoirs us...As the main unconventional natural gas reservoirs,shale gas reservoirs and coalbed methane(CBM)reservoirs belong to adsorptive gas reservoirs,i.e.,gas reservoirs containing adsorbed gas.Shale gas and CBM reservoirs usually have the characteristics of rich adsorbed gas and obvious dynamic changes of porosity and permeability.A generalized material balance equation and the corresponding reserve evaluation method considering all the mechanisms for both shale gas reservoirs and CBM reservoirs are necessary.In this work,a generalized material balance equation(GMBE)considering the effects of critical desorption pressure,stress sensitivity,matrix shrinkage,water production,water influx,and solubility of natural gas in water is established.Then,by converting the GMBE to a linear relationship between two parameter groups related with known formation/fluid properties and dynamic performance data,the straight-line reserve evaluation method is proposed.By using the slope and the y-intercept of this straight line,the original adsorbed gas in place(OAGIP),original free gas in place(OFGIP),original dissolved gas in place(ODGIP),and the original gas in place(OGIP)can be quickly calculated.Third,two validation cases for shale gas reservoir and CBM reservoir are conducted using commercial reservoir simulator and the coalbed methane dynamic performance analysis software,respectively.Finally,two field studies in the Fuling shale gas field and the Baode CBM field are presented.Results show that the GMBE and the corresponding straight-line reserve evaluation method are rational,accurate,and effective for both shale gas reservoirs and CBM reservoirs.More detailed information about reserves of shale gas and CBM reservoirs can be clarified,and only the straight-line fitting approach is used to determine all kinds of reserves without iteration,proving that the proposed method has great advantages compared with other current methods.展开更多
We applied the material balance principle of the denudation volume and sedimentary flux to study the denudation-accumulation system between the Longmen Mountains(Mts.)and the foreland basin.The amount of sediment in e...We applied the material balance principle of the denudation volume and sedimentary flux to study the denudation-accumulation system between the Longmen Mountains(Mts.)and the foreland basin.The amount of sediment in each sedimentation stage of the basin was estimated to obtain the denudation volume,erosion thickness and deposit thickness since the Late Triassic Epoch,to enable us to recover the paleoelevation of the provenance and the sedimentary area.The results show the following:(1)Since the Late Triassic Epoch,the elevation of the surface of the Longmen Mts.has uplifted from 0 m to 2751 m,and the crust of the Longmen Mts.has uplifted by 9.8 km.Approximately 72%of the materials introduced have been denuded from the mountains.(2)It is difficult to recover the paleoelevation of each stage of the Longmen Mts.foreland basin quantitatively by the present-day techniques and data.(3)The formation of the Longmen Mts.foreland basin consisted of three stages of thrust belt tectonic load and three stages of thrust belt erosional unload.During tectonic loading stages(Late Triassic Epoch,Late Jurassic-Early Cretaceous,Late Cretaceous-Miocene),the average elevation of Longmen Mts.was lower(approximately 700-1700 m).During erosional unloading stages(Early and Middle Jurassic,Middle Cretaceous and Jiaguan,Late Cenozoic),the average elevation of Longmen Mts.was high at approximately 2000-2800m.展开更多
Implementing a CO2 flooding scheme successfully requires the capacity to get accurate information of reservoir dynamic performance and fluids injected. Despite some numerical simulation studies, the complicated drive ...Implementing a CO2 flooding scheme successfully requires the capacity to get accurate information of reservoir dynamic performance and fluids injected. Despite some numerical simulation studies, the complicated drive mechanisms and actual reservoir performance have not been fully understood. There is a strong need to develop models from different perspectives to complement current simulators and provide valuable insights into the reservoir performance during CO2 flooding. The aim of this study is to develop a model by using an improved material balance equation （MBE） to analyze quickly the performance of CO2 flooding. After matching the historical field data the proposed model can be used to evaluate, monitor and predict the overall reservoir dynamic performance during CO2 flooding. In order to account accurately for the complex displacement process involving compositional effect and multiphase flow, the PVT properties and flowability of reservoir fluids are incorporated in the model. This study investigates the effects of a number of factors, such as reservoir pressure, the amount of CO2 injected, the CO2 partition ratios in reservoir fluids, the possibility of the existence of a free CO2 gas cap, the proportion of reservoir fluids contacted with CO2, the starting time of CO2 flooding, oil swelling, and oil flowability improvement by mixing with CO2. The model was used to analyze the CO2 flooding project in Weyburn oil field, Saskatchewan, Canada. This study shows that the proposed model is an effective complementary tool to analyze and monitor the overall reservoir performance during CO2 flooding.展开更多
In order to clarify the characteristics of non-uniform water invasion in water-bearing gas reservoirs,it is necessary to introduce the nonuniformity coefficient(A)and water invasion constant(B)to characterize the non-...In order to clarify the characteristics of non-uniform water invasion in water-bearing gas reservoirs,it is necessary to introduce the nonuniformity coefficient(A)and water invasion constant(B)to characterize the non-uniformity degree of reservoir physical properties and the activity degree of peripheral water,respectively,based on the dual mechanism of water invasion to recharge the formation energy and seal off the gas in the reservoir.Then,the material balance method considering the phenomenon of water sealed gas was established.On this basis,the water invasion characteristic curve chart of water-bearing gas reservoirs was plotted,and the non-uniform water invasion mode was classified based on the example gas reservoir.And the following research results were obtained.First,in the water invasion characteristic curve chart of waterbearing gas reservoirs which is plotted based on the material balance method considering the influence of water sealed gas,the upper right area and the lower left area are defined as recharge area and seal area,respectively.By taking A=0 and B=2 as the boundary,the recharge area is divided into strong recharge area and weak recharge area.By taking A=2 and B=2 as the boundary,the seal area is divided into strong seal area and weak seal area.And correspondingly there are four water invasion modes,i.e.,strong recharge,weak recharge,weak seal and strong seal.Second,for fractured gas reservoirs,the non-uniformity degree of reservoir physical properties is high,and water sealed gas can be formed easily after water invasion.The dimensionless relative pseudo-pressure data of this type of gas reservoir is located in the seal area of the water invasion characteristic curve chart.Third,for the gas reservoirs whose reservoir physical properties are relatively uniform,the dimensionless relative pseudo-pressure data is located in the recharge area of the water invasion characteristic curve chart,and the recharge effect of water invasion on formation energy is greater than the weakening effect of water sealed gas on formation energy.Fourth,with the increase of A,the non-uniformity degree of reservoir physical properties increases,the water invasion characteristic curve shifts from the upper right to the lower left,and the recovery factor of gas reservoir decreases continuously.With the increase of B,the recharge effect of water invasion on formation energy and the weakening effect of water sealed gas on formation energy are both weakened,the distribution range of water invasion characteristic curve narrows to the recharge/seal boundary,and the corresponding range of gas reservoir recovery factor also narrows.展开更多
It is difficult to determine the effective reservoir rock compressibility,aquifer volume and water influx of high pressure and ultra-high pressure gas reservoirs,so when the traditional apparent reservoir pressure and...It is difficult to determine the effective reservoir rock compressibility,aquifer volume and water influx of high pressure and ultra-high pressure gas reservoirs,so when the traditional apparent reservoir pressure and cumulative gas production curve extrapolation method and its modified version are used to calculate the initial gas in-place of such gas reservoirs,the calculation accuracy is lower.The material balance equation in the form of power function for such gas reservoirs was established based on Gonzalez method to improve the accuracy and reliability of reserve evaluation.Then,based on 20 high pressure and ultra-high pressure reservoirs that had been developed abroad,the empirical value of the power exponent was defined,and the influences of the depletion degree of apparent reservoir pressure and the degree of reserve recovery on the reliability of reserve calculation were analyzed.Besides,the critical value of the key parameter affecting the reliability of reserve evaluation(depletion degree of apparent reservoir pressure)was determined and compared with the critical value of the two-linear trends.Finally,an example calculation was carried out.And the following research results were obtained.First,the empirical value of the power exponent calculated using the material balance method in the form of power function is 1.02847,with an upper limit of 1.11567.Second,the depletion degree of apparent reservoir pressure corresponding to the inflection point of the classical two-linear trends ranges from 0.14 to 0.38 with an average of 0.23,while that corresponding to the extrapolation point of the second straight line is between 0.23 and 0.50 with an average of 0.33,and the corresponding degree of reserve recovery is in the range of 33%-65%with an average of 45%.Third,the reserves of such high pressure gas reservoirs calculated with this new method has an error rate less than 10%if the depletion degree of apparent reservoir pressure is greater than 0.33.In conclusion,for such high pressure gas reservoirs and the stress-sensitive fractured gas reservoirs,the material balance method in the form of power function proposed in this paper can avoid the uncertainty parameters(e.g.effective reservoir rock compressibility,aquifer volume and water influx)and it is advantageous with simple calculation process,better practicability and small error.展开更多
This study aims to improve the evaluation of residual oil saturation in water flooded zones based on the material balance model(MBM)with variable multiple for injected water.We investigated the change patterns of rock...This study aims to improve the evaluation of residual oil saturation in water flooded zones based on the material balance model(MBM)with variable multiple for injected water.We investigated the change patterns of rock-electro parameters during waterflooding through the analysis of displacement tests.Our work differentiated the waterflooding into numerous displacement processes and accordingly propose an improved time-differentiated variable multiple MBM.The calculation results of the improved model are more consistent with the displacement experiment data of cores.Furthermore,the improved method was integrated into the comprehensive interpretation platform of offshore logging to analyze water flooded zones of a well in the A oilfield.As a result,the residual oil saturation calculated is in close agreement with the results of experiments on cores.Our results indicate that the time-differentiation and variable multiplier for injected water can effectively enhance the assessment accuracy of the residual oil saturation of water-flooded zones.展开更多
Accurately predicting the estimated ultimate recovery(EUR)of shale gas wells is key to formulating a shale gas reservoir development plan.However,in practice,determining the EUR remains challenging due to the complex ...Accurately predicting the estimated ultimate recovery(EUR)of shale gas wells is key to formulating a shale gas reservoir development plan.However,in practice,determining the EUR remains challenging due to the complex dynamic characteristics of shale gas production,which first decreases rapidly and then slowly.In this study,based on material balance theory and equivalent seepage resistance theory and considering crucial factors including primary water,adsorption,and pore effects,a new production model for fractured horizontal shale gas wells is developed.The calculation process is designed by using Newton's iterative method.The shale gas well EUR prediction method is verified,and the factors influencing the EUR are analyzed.The results show that adsorption has a significant effect on production,especially on the Langmuir volume.Moreover,ignoring the influence of primary water,which exists in shale gas reservoirs in the form of bound water,results in an overestimation of the EUR.Furthermore,production positively correlates with the fracture half-length and the number of fractures,but the action mechanisms of these two factors differ.Unlike the number of fractures,which predominantly affects the initial stage of production,the fracture half-length has a more nuanced role.It is capable of altering the stimulated reservoir volume zone,thereby exerting influence over the entire production life cycle.展开更多
Ultra-deepmajor gas fields are typically characterized by high and ultra-high pressure,tightmatrix and developed fractures,so the reserve estimation is of higher uncertainty.In order to accurately estimate the reserve...Ultra-deepmajor gas fields are typically characterized by high and ultra-high pressure,tightmatrix and developed fractures,so the reserve estimation is of higher uncertainty.In order to accurately estimate the reserves of this type of gas reservoir,this paper analyzed the correlation between the effective rock compressibility and the cumulative effective rock compressibility based on the material balance equation of high and ultra-high pressure gas reservoirs,and accordingly selected the material balance based analysis method suitable for the reserves estimation of high and ultra-high pressure gas reservoirs.Then,the starting calculation conditions of reserve estimation were determined using the non-linear regressionmethod.In addition,a semilogarithmic type curvematchingmethodwas established for the caseswhere the starting conditions could not bemet.Finally,thismethodwas applied to calculate the reserves of three ultra-high pressure gas fields(reservoirs)to verify its reliability.And the following research results were obtained.First,the cumulative effective compressibility of gas reservoir in thematerial balance equation of high and ultra-high pressure gas reservoir is a key parameter influencing its reserves,and it is the function of original formation pressure and current average formation pressure,but its numerical value can be hardly obtained by core experiments.Second,it is recommended to adopt the nonlinear regressionmethod without compressibility to estimate the reserves of high and ultra-high pressure gas reservoirs.Third,the calculation starting point of reserves by the nonlinear regression method(the starting point of dimensionless apparent formation pressure-cumulative gas production curve deviating from the straight line relationship)cannot be theoretically calculated.The calculation starting point for different dimensionless linear coefficients(uD)obtained fromthe statistical results by the graphic method corresponds to the dimensionless apparent pressure depletion degree of 0.06-0.38,and that obtained based on the data statistics of the example gas reservoir falls within this interval.Fourth,when the starting conditions are not satisfied,the semi-logarithmic type curve matching method can be used for reserve estimation.The ratio of the reserves to the apparent geological reservesG/G_(app) is a function of uD.The higher the uD,the lower the G/G_(app).Fifth,for the high and ultra-high pressure gas reservoirs in the production test stage,the test production time shall be extended as long as possible to improve the reliability of reserve estimation.And for those in the middle and late stages of development,it is necessary to prepare the comprehensive treatment measures on the basis of reserves so as to improve the development effects of gas reservoirs continuously.展开更多
Oilfield M currently has a comprehensive water cut of 73.2%after more than 20 years of development,the reservoir is experiencing both edge-bottom water flooding and injection water flooding,with diverse types of injec...Oilfield M currently has a comprehensive water cut of 73.2%after more than 20 years of development,the reservoir is experiencing both edge-bottom water flooding and injection water flooding,with diverse types of injected water and complex flooding patterns,necessitating the research on logging evaluation methods for water-flooded layers.By introducing the variable multiple injection water material balance theory and combining it with the rock-electric relationship,an analysis of the water flooding mechanism in the study area was conducted.This led to the establishment of the variation characteristics between formation resistivity,water production rate,and saturation under different reservoir types and different salinities of injected water in the area;using the semi-permeable membrane capillary pressure experiment,the relationship between the original formation resistivity and the oil column height was established,deriving the relationship between the water production rate and the formation resistivity drop rate,combining the analysis of the water flooding mechanism mentioned above,allowing for a quantitative assessment of the level of water flooding;optimizing the mixed formation water resistivity calculation model to accurately determine parameters such as remaining oil saturation and water production rate,a set of identification and quantitative evaluation methods for waterflooded layers in Oilfield M was formed.The interpretation accuracy reached 87.5%,providing strong technical support for selecting perforation layers in the oilfield and avoiding highly flooded layers.This is of significant application value for the remaining oil evaluation and efficient development of water-flooded layers in overseas clastic rock oilfields.展开更多
Sludge concentration subarea(A area and B area) is realized by mesh filter unit,solving the higher sludge concentration process problem of MBR system under zero excess sludge discharge conditions.Mass balance of the s...Sludge concentration subarea(A area and B area) is realized by mesh filter unit,solving the higher sludge concentration process problem of MBR system under zero excess sludge discharge conditions.Mass balance of the system is processed,and variety disciplinarians of VSS of A area and B area are analyzed.The results show that XA decreases while HRTA increases.XB decreases while R increases,and ascends as VSS(XA,B) of mesh effluent increases.When XB is a fixed value,XA,B increases as R does and XA decreases slowly while R increases,which theoretically proves the feasibility of the technique.展开更多
The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accu...The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accumulation. However, there are problems, such as whether high-quality source rocks exist or not？ What high-quality source rocks are, and how to identify them, are yet to be agreed upon. Aimed at this issue of concern to explorationists, and taking the Beier Sag in the Hailaer Basin as an example, this paper defines the high-quality source rocks and the lower limit for evaluation of high-quality source rocks, by using the inflection point on the relationship curve of hydrocarbon （oil） expulsion, which is calculated by the material balance principle, versus total organic carbon （TOC）. The results show that when TOC is low, all source rocks have limited hydrocarbon expulsion and slow growth rate, thus they cannot be high-quality source rocks. However, when TOC rises to some threshold, hydrocarbon expulsion increases significantly with TOC. This inflection point should be the lower limit of high-quality source rocks： those with TOC greater than the inflection-point value are high-quality source rocks. In addition, the lower limit of high-quality source rocks is also related to the type and maturity of organic matters in the source rocks, as well as the mineral components of the source rocks affecting the residual hydrocarbons. Theoretically, the lower limit of high-quality source rocks depends on geological conditions rather than being a constant value. However, for the sake of simplicity and practicability, in this paper TOC=2.0% is regarded as the lower limit of high-quality source rocks. The examination of such standard in the work area indicates that the high-quality source rocks in members K^n2 and K^n~ of the Nantun formation contribute 76% and 82% to oil generation, and 96% and 91% to oil expulsion, respectively. The distribution of high-quality source rocks is also closely related to the distribution of hydrocarbon reservoirs in the region, demonstrating that high-quality source rocks control hydrocarbon accumulation.展开更多
In this work,a flowing material balance equation(FMBE)is established for under saturated coalbed methane(CBM)reservoirs,which considers immobile free gas expansion effect at the dewatering stage.Based on the establish...In this work,a flowing material balance equation(FMBE)is established for under saturated coalbed methane(CBM)reservoirs,which considers immobile free gas expansion effect at the dewatering stage.Based on the established FMBE,five straight-line methods are proposed to determine the control area,initial water reserve,initial free gas reserve,initial adsorbed gas reserve,original gas in place,as well as permeability at the same time.Subsequently,the proposed FMBE methods for undersaturated CBM reservoirs are validated against a reservoir simulation software with and without considering free gas expansion.Finally,the proposed methods are applied in a field case when considering free gas expansion effect.Validation cases show that the straight-line relationships for the proposed five FMBE methods are excellent,and good agreements are obtained among the actual reserves and permeabilities and those evaluated by the proposed five FMBE methods,indicating the proposed five FMBE methods are effective and rational for CBM reservoirs.Results show that a small amount of free gas will result in a great deviation in reserve evaluation;hence,the immobile free gas expansion effect should be considered when establishing the material balance equation of undersaturated CBM reservoirs at the dewatering stage.展开更多
Flue gas fooding is one of the important technologies to improve oil recovery and achieve greenhouse gas storage.In order to study multicomponent fue gas storage capacity and enhanced oil recovery(EOR)performance of f...Flue gas fooding is one of the important technologies to improve oil recovery and achieve greenhouse gas storage.In order to study multicomponent fue gas storage capacity and enhanced oil recovery(EOR)performance of fue gas water-alternating gas(fue gas-WAG)injection after continuous waterfooding in an oil reservoir,a long core fooding system was built.The experimental results showed that the oil recovery factor of fue gas-WAG fooding was increased by 21.25%after continuous waterfooding and fue gas-WAG fooding could further enhance oil recovery and reduce water cut signifcantly.A novel material balance model based on storage mechanism was developed to estimate the multicomponent fue gas storage capacity and storage capacity of each component of fue gas in reservoir oil,water and as free gas in the post-waterfooding reservoir.The ultimate storage ratio of fue gas is 16%in the fue gas-WAG fooding process.The calculation results of fue gas storage capacity showed that the injection gas storage capacity mainly consists of N_(2) and CO_(2),only N_(2) exists as free gas phase in cores,and other components of injection gas are dissolved in oil and water.Finally,injection strategies from three perspectives for fue gas storage,EOR,and combination of fue gas storage and EOR were proposed,respectively.展开更多
Copper smelting is a significant source of SO2 emission. It is important to quantify SO2 emissions from combustion sources for regulatory and control purposes in relation to air quality. The characteristics of SO2 emi...Copper smelting is a significant source of SO2 emission. It is important to quantify SO2 emissions from combustion sources for regulatory and control purposes in relation to air quality. The characteristics of SO2 emissions from copper smelting industry in Yurman Province, China, were examined. Analysis based on the present situation, material balance and measuring method were used to confirm SO2 emission factors of copper smelting industry. Results show that SO2 emission factors for Isa system, side blown-continuous converting system （SB-CC）, blast furnace-continuous converting systems （B-CC） and blast furnace-converter blowing （B-C） are 11.69-18.64, 62.44--101.4, 19.43-37.88 and 45.48-81.03 kg/t（blister copper）, respectively. The comprehensive emission factor based on all smelting plants is found to be in the range of 23-39.99 kg-SO2/t（blister copper） for Yunnan Province, China. The results are compared with those for discharge coefficients of industrial pollutants in the First National General Survey of Pollution Sources and the emission factor of the total amount of major pollutants. It is observed that there are some differences among emission factors.展开更多
Based on the principle of thermal balance and material balance of lime furnace, the reaction and heat transfer process mathematical-physical model and the on-line monitoring model of the decomposition rate of limeston...Based on the principle of thermal balance and material balance of lime furnace, the reaction and heat transfer process mathematical-physical model and the on-line monitoring model of the decomposition rate of limestone were set up. With this model, numerical simulation is used to analyze the effects of operational parameters on the process of lime calcining and to optimize it. By using visual basic program to communicate and program, the centralized management and automatic control of the lime furnace are realized. The software is put into practical production, which makes the lime furnace operate steadily and efficiently, and causes the increase in output and decrease in energy consumption.展开更多
This paper presents two methods for easy determination of water influx in reservoirs based on the material balance theory of reservoirs,i.e.,the Net Production Volume Curve,and the Production Index Curve.These methods...This paper presents two methods for easy determination of water influx in reservoirs based on the material balance theory of reservoirs,i.e.,the Net Production Volume Curve,and the Production Index Curve.These methods can be used for esti-ma tion of water influx in reservoirs without any assumption of aquifer shape and size by applying the production performance data.Hence the tedium of the c onventional trial-and-error calculations and obvious uncertainty could be over come in ap plication of the easy and practical new methods.展开更多
Aerosol observation was conducted for four seasons from September 2001 to August 2002 at five sampling sites in Hangzhou, South China, on PM10 mass, 22 elements （Na, Mg, AI, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu...Aerosol observation was conducted for four seasons from September 2001 to August 2002 at five sampling sites in Hangzhou, South China, on PM10 mass, 22 elements （Na, Mg, AI, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As. Se, Br, Cd, Ba, and Pb）, 5 major ions （F^-, Cl^ , NO3^-, SO4^2- , and NH4^＋）, and organic and elemental carbon （OC and EC）, showing that PM10 mass ranged from 46.7 to 270.8 μg/m^3, with an annual average of 119.2 μg/m^3. Na, AI, Si, S, K, Ca, and Fe were the most abundant elements in PM10, most of S being in the form of SO4^2- . SO4^2-, NO3^-, and NH4^＋ were the major ions, which contributed to about 20% of the PM10 mass. The mean seasonal concentrations for SO4^2- , averaged over all sites, were found to be 18.0, 18.5, 24,Z and 21.4 μg/m^3, for spring, summer, autumn, and winter, respectively, while the corresponding loadings for NO3^- were 7.2, 4.7, 7.1, and 11.2 μg/m^3, and for NH4^＋ were 6.0, 5.9, 8.2, and 9.3 μg/m^3, in the form mostly of NH4NO3 in spring, autumn, and winter, and mostly of （NH4）2SO4 in summer. The low NO3^-/SO4^2- ratio found indicates coal combustion as the major source throughout the year. The mean annual concentrations of OC and EC in PM10 were found to be 21.4, and 4.1 μg/m^3, respectively. Material balance calculation indicated that fugitive dust, the secondary aerosol, and carbonaceous matter were the most abundant species in PM10 for the four seasons, as is characteristic for cities in South China.展开更多
Due to the extremely low permeability of shale formations,the combination of horizontal well and volume fracturing has been proposed as an effective technique to improve the production of Dagang continental shale oil ...Due to the extremely low permeability of shale formations,the combination of horizontal well and volume fracturing has been proposed as an effective technique to improve the production of Dagang continental shale oil reservoirs.Based on the flow material balance method(FMB)and straight-line analysis(SLA)method,the stimulated reservoir volume(SRV)and drainage volume are determined to identify the flow regimes of the seepage mechanism of shale oil reservoirs.To resolve the challenges of multi-scaled flow regimes and bottom hole pressure(BHP)variation before and after pumping in shale oil wells,a multi-linear analytical flow model was established to predict the future production and the final expected ultimate recoverable oil(EURo)after fitting the historical production dynamics.Based on the results,it can be concluded that the flow regime of a shale oil well in production can be divided into two stages consisting of linear flow within SRV and composite flow from the un-stimulated area to SRV.The effects of fracturing operation parameters,such as fracturing fluid volume and sand/liquid ratio,on shale oil productivity,are analyzed,and insightful suggestions are drawn for the future development of this pay zone.展开更多
基金supported by the Ministry of Science and Technology of China (No.2010DFA22770)the National Science and Technology Support Program of China (No.2010BAC66B04)the Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province (No.AE201003)
文摘The organic matter degradation process during anaerobic co-digestion of municipal biomass waste （MBW） and waste-activated sludge （WAS） under different organic loading rates （OLRs） was investigated in bench-scale and pilot-scale semi-continuous stirred tank reactors. To better understand the degradation process of MBW and WAS co-digestion and provide theoretical guidance for engineering application, anaerobic digestion model No. 1 was revised for the co-digestion of MBW and WAS. The results showed that the degradation of organic matter could be characterized into three different fractions, including readily hydrolyzable organics, easily degradable particulate organics, and recalcitrant particle organics. Hydrolysis was the rate-limiting step under lower OLRs, and methanogenesisis was the rate-limiting step for an OLR of 8.0 kg volatile solid （VS）/（m^3·day）. The hydrolytic parameters of carbohydrate, protein, and lipids were 0.104, 0.083, and 0.084 kg chemical oxygen demand （COD）/（kg COD·hr）, respectively, and the reaction rate parameters of lipid fermentation were 1 and 1.25 kg COD/（kg COD.hr） for OLRs of 4.0 and 6.0 kg VS/（m^3·day）. A revised model was used to simulate methane yield, and the results fit well with the experimental data. Material balance data were acquired based on the revised model, which showed that 58.50% of total COD was converted to methane.
基金supported by the National Natural Science Foundation of China(No.52104018,52274030)China National Petroleum Corporation(CNPC)Innovation Foundation(No.2024DQ02-0303)China National Petroleum Corporation(CNPC)14th Five-Year Plan Major Strategic Scientific and Technological Project for Prospective and Fundamental Research(2024DJ86).
文摘Carbonate gas reservoirs are often characterized by strong heterogeneity,complex inter-well connectivity,extensive edge or bottom water,and unbalanced production,challenges that are also common in many heterogeneous gas reservoirs with intricate storage and flow behavior.To address these issues within a unified,data-driven framework,this study develops a multi-block material balance model that accounts for inter-block flow and aquifer influx,and is applicable to a wide range of reservoir types.The model incorporates inter-well and well-group conductive connectivity together with pseudo–steady-state aquifer support.The governing equations are solved using a Newton–Raphson scheme,while particle swarm optimization is employed to estimate formation pressures,inter-well connectivity,and effective aquifer volumes.An unbalanced exploitation factor,UEF,is introduced to quantify production imbalance and to guide development optimization.Validation using a synthetic reservoir model demonstrates that the approach accurately reproduces pressure evolution,crossflow behavior,and water influx.Application to a representative case(the Longwangmiao)field further confirms its robustness under highly heterogeneous conditions,achieving a 12.9%reduction in UEF through optimized production allocation.
基金supported by Science and Technology Major Project of Shanxi Province,China(No.20201101002)Science and Technology Major Project of China,China(No.2016ZX05043002)+1 种基金National Natural Science Foundation Project of China,China(No.51874319)Science Foundation of China University of Petroleum(Beijing),China(No.2462020QNXZ003)to support part of this work
文摘As the main unconventional natural gas reservoirs,shale gas reservoirs and coalbed methane(CBM)reservoirs belong to adsorptive gas reservoirs,i.e.,gas reservoirs containing adsorbed gas.Shale gas and CBM reservoirs usually have the characteristics of rich adsorbed gas and obvious dynamic changes of porosity and permeability.A generalized material balance equation and the corresponding reserve evaluation method considering all the mechanisms for both shale gas reservoirs and CBM reservoirs are necessary.In this work,a generalized material balance equation(GMBE)considering the effects of critical desorption pressure,stress sensitivity,matrix shrinkage,water production,water influx,and solubility of natural gas in water is established.Then,by converting the GMBE to a linear relationship between two parameter groups related with known formation/fluid properties and dynamic performance data,the straight-line reserve evaluation method is proposed.By using the slope and the y-intercept of this straight line,the original adsorbed gas in place(OAGIP),original free gas in place(OFGIP),original dissolved gas in place(ODGIP),and the original gas in place(OGIP)can be quickly calculated.Third,two validation cases for shale gas reservoir and CBM reservoir are conducted using commercial reservoir simulator and the coalbed methane dynamic performance analysis software,respectively.Finally,two field studies in the Fuling shale gas field and the Baode CBM field are presented.Results show that the GMBE and the corresponding straight-line reserve evaluation method are rational,accurate,and effective for both shale gas reservoirs and CBM reservoirs.More detailed information about reserves of shale gas and CBM reservoirs can be clarified,and only the straight-line fitting approach is used to determine all kinds of reserves without iteration,proving that the proposed method has great advantages compared with other current methods.
基金the Project of the National Natural Science Foudation of China(Grant No.41372114,41340005,41172162,40972083)
文摘We applied the material balance principle of the denudation volume and sedimentary flux to study the denudation-accumulation system between the Longmen Mountains(Mts.)and the foreland basin.The amount of sediment in each sedimentation stage of the basin was estimated to obtain the denudation volume,erosion thickness and deposit thickness since the Late Triassic Epoch,to enable us to recover the paleoelevation of the provenance and the sedimentary area.The results show the following:(1)Since the Late Triassic Epoch,the elevation of the surface of the Longmen Mts.has uplifted from 0 m to 2751 m,and the crust of the Longmen Mts.has uplifted by 9.8 km.Approximately 72%of the materials introduced have been denuded from the mountains.(2)It is difficult to recover the paleoelevation of each stage of the Longmen Mts.foreland basin quantitatively by the present-day techniques and data.(3)The formation of the Longmen Mts.foreland basin consisted of three stages of thrust belt tectonic load and three stages of thrust belt erosional unload.During tectonic loading stages(Late Triassic Epoch,Late Jurassic-Early Cretaceous,Late Cretaceous-Miocene),the average elevation of Longmen Mts.was lower(approximately 700-1700 m).During erosional unloading stages(Early and Middle Jurassic,Middle Cretaceous and Jiaguan,Late Cenozoic),the average elevation of Longmen Mts.was high at approximately 2000-2800m.
文摘Implementing a CO2 flooding scheme successfully requires the capacity to get accurate information of reservoir dynamic performance and fluids injected. Despite some numerical simulation studies, the complicated drive mechanisms and actual reservoir performance have not been fully understood. There is a strong need to develop models from different perspectives to complement current simulators and provide valuable insights into the reservoir performance during CO2 flooding. The aim of this study is to develop a model by using an improved material balance equation （MBE） to analyze quickly the performance of CO2 flooding. After matching the historical field data the proposed model can be used to evaluate, monitor and predict the overall reservoir dynamic performance during CO2 flooding. In order to account accurately for the complex displacement process involving compositional effect and multiphase flow, the PVT properties and flowability of reservoir fluids are incorporated in the model. This study investigates the effects of a number of factors, such as reservoir pressure, the amount of CO2 injected, the CO2 partition ratios in reservoir fluids, the possibility of the existence of a free CO2 gas cap, the proportion of reservoir fluids contacted with CO2, the starting time of CO2 flooding, oil swelling, and oil flowability improvement by mixing with CO2. The model was used to analyze the CO2 flooding project in Weyburn oil field, Saskatchewan, Canada. This study shows that the proposed model is an effective complementary tool to analyze and monitor the overall reservoir performance during CO2 flooding.
基金Project supported by the PetroChina-SWPU Innovation Alliance's technological cooperation project(No.2020CX010402).
文摘In order to clarify the characteristics of non-uniform water invasion in water-bearing gas reservoirs,it is necessary to introduce the nonuniformity coefficient(A)and water invasion constant(B)to characterize the non-uniformity degree of reservoir physical properties and the activity degree of peripheral water,respectively,based on the dual mechanism of water invasion to recharge the formation energy and seal off the gas in the reservoir.Then,the material balance method considering the phenomenon of water sealed gas was established.On this basis,the water invasion characteristic curve chart of water-bearing gas reservoirs was plotted,and the non-uniform water invasion mode was classified based on the example gas reservoir.And the following research results were obtained.First,in the water invasion characteristic curve chart of waterbearing gas reservoirs which is plotted based on the material balance method considering the influence of water sealed gas,the upper right area and the lower left area are defined as recharge area and seal area,respectively.By taking A=0 and B=2 as the boundary,the recharge area is divided into strong recharge area and weak recharge area.By taking A=2 and B=2 as the boundary,the seal area is divided into strong seal area and weak seal area.And correspondingly there are four water invasion modes,i.e.,strong recharge,weak recharge,weak seal and strong seal.Second,for fractured gas reservoirs,the non-uniformity degree of reservoir physical properties is high,and water sealed gas can be formed easily after water invasion.The dimensionless relative pseudo-pressure data of this type of gas reservoir is located in the seal area of the water invasion characteristic curve chart.Third,for the gas reservoirs whose reservoir physical properties are relatively uniform,the dimensionless relative pseudo-pressure data is located in the recharge area of the water invasion characteristic curve chart,and the recharge effect of water invasion on formation energy is greater than the weakening effect of water sealed gas on formation energy.Fourth,with the increase of A,the non-uniformity degree of reservoir physical properties increases,the water invasion characteristic curve shifts from the upper right to the lower left,and the recovery factor of gas reservoir decreases continuously.With the increase of B,the recharge effect of water invasion on formation energy and the weakening effect of water sealed gas on formation energy are both weakened,the distribution range of water invasion characteristic curve narrows to the recharge/seal boundary,and the corresponding range of gas reservoir recovery factor also narrows.
基金Project supported by Major Special Science and Technology Project of PetroChina Company Limited“Study and application of key technologies for developing deepeultra-deep gas in Kuqa depression”(No.:2018E-1803).
文摘It is difficult to determine the effective reservoir rock compressibility,aquifer volume and water influx of high pressure and ultra-high pressure gas reservoirs,so when the traditional apparent reservoir pressure and cumulative gas production curve extrapolation method and its modified version are used to calculate the initial gas in-place of such gas reservoirs,the calculation accuracy is lower.The material balance equation in the form of power function for such gas reservoirs was established based on Gonzalez method to improve the accuracy and reliability of reserve evaluation.Then,based on 20 high pressure and ultra-high pressure reservoirs that had been developed abroad,the empirical value of the power exponent was defined,and the influences of the depletion degree of apparent reservoir pressure and the degree of reserve recovery on the reliability of reserve calculation were analyzed.Besides,the critical value of the key parameter affecting the reliability of reserve evaluation(depletion degree of apparent reservoir pressure)was determined and compared with the critical value of the two-linear trends.Finally,an example calculation was carried out.And the following research results were obtained.First,the empirical value of the power exponent calculated using the material balance method in the form of power function is 1.02847,with an upper limit of 1.11567.Second,the depletion degree of apparent reservoir pressure corresponding to the inflection point of the classical two-linear trends ranges from 0.14 to 0.38 with an average of 0.23,while that corresponding to the extrapolation point of the second straight line is between 0.23 and 0.50 with an average of 0.33,and the corresponding degree of reserve recovery is in the range of 33%-65%with an average of 45%.Third,the reserves of such high pressure gas reservoirs calculated with this new method has an error rate less than 10%if the depletion degree of apparent reservoir pressure is greater than 0.33.In conclusion,for such high pressure gas reservoirs and the stress-sensitive fractured gas reservoirs,the material balance method in the form of power function proposed in this paper can avoid the uncertainty parameters(e.g.effective reservoir rock compressibility,aquifer volume and water influx)and it is advantageous with simple calculation process,better practicability and small error.
文摘This study aims to improve the evaluation of residual oil saturation in water flooded zones based on the material balance model(MBM)with variable multiple for injected water.We investigated the change patterns of rock-electro parameters during waterflooding through the analysis of displacement tests.Our work differentiated the waterflooding into numerous displacement processes and accordingly propose an improved time-differentiated variable multiple MBM.The calculation results of the improved model are more consistent with the displacement experiment data of cores.Furthermore,the improved method was integrated into the comprehensive interpretation platform of offshore logging to analyze water flooded zones of a well in the A oilfield.As a result,the residual oil saturation calculated is in close agreement with the results of experiments on cores.Our results indicate that the time-differentiation and variable multiplier for injected water can effectively enhance the assessment accuracy of the residual oil saturation of water-flooded zones.
基金supported by the National Natural Science Foundation of China(Grant Nos.52304024,52274034,and 52204035)the Natural Science Foundation of Chongqing,China(Grant No.CSTB2023NSCQ-MSX0264)+1 种基金the Project of Science and Technology Research Program of Chongqing Municipal Education Commission,China(Grant Nos.KJQN202201517 and KJQN202001501)the Research Foundation of the Chongqing University of Science and Technology,China(Grant No.ckrc2022025).
文摘Accurately predicting the estimated ultimate recovery(EUR)of shale gas wells is key to formulating a shale gas reservoir development plan.However,in practice,determining the EUR remains challenging due to the complex dynamic characteristics of shale gas production,which first decreases rapidly and then slowly.In this study,based on material balance theory and equivalent seepage resistance theory and considering crucial factors including primary water,adsorption,and pore effects,a new production model for fractured horizontal shale gas wells is developed.The calculation process is designed by using Newton's iterative method.The shale gas well EUR prediction method is verified,and the factors influencing the EUR are analyzed.The results show that adsorption has a significant effect on production,especially on the Langmuir volume.Moreover,ignoring the influence of primary water,which exists in shale gas reservoirs in the form of bound water,results in an overestimation of the EUR.Furthermore,production positively correlates with the fracture half-length and the number of fractures,but the action mechanisms of these two factors differ.Unlike the number of fractures,which predominantly affects the initial stage of production,the fracture half-length has a more nuanced role.It is capable of altering the stimulated reservoir volume zone,thereby exerting influence over the entire production life cycle.
基金supported by the Major Science and Technology Project of PetroChina Company Limited“Research and Application of Key Technologies for Development of Deep and Ultra-deep Gas Fields in Kuqa Depression”(No.2018E-1803).
文摘Ultra-deepmajor gas fields are typically characterized by high and ultra-high pressure,tightmatrix and developed fractures,so the reserve estimation is of higher uncertainty.In order to accurately estimate the reserves of this type of gas reservoir,this paper analyzed the correlation between the effective rock compressibility and the cumulative effective rock compressibility based on the material balance equation of high and ultra-high pressure gas reservoirs,and accordingly selected the material balance based analysis method suitable for the reserves estimation of high and ultra-high pressure gas reservoirs.Then,the starting calculation conditions of reserve estimation were determined using the non-linear regressionmethod.In addition,a semilogarithmic type curvematchingmethodwas established for the caseswhere the starting conditions could not bemet.Finally,thismethodwas applied to calculate the reserves of three ultra-high pressure gas fields(reservoirs)to verify its reliability.And the following research results were obtained.First,the cumulative effective compressibility of gas reservoir in thematerial balance equation of high and ultra-high pressure gas reservoir is a key parameter influencing its reserves,and it is the function of original formation pressure and current average formation pressure,but its numerical value can be hardly obtained by core experiments.Second,it is recommended to adopt the nonlinear regressionmethod without compressibility to estimate the reserves of high and ultra-high pressure gas reservoirs.Third,the calculation starting point of reserves by the nonlinear regression method(the starting point of dimensionless apparent formation pressure-cumulative gas production curve deviating from the straight line relationship)cannot be theoretically calculated.The calculation starting point for different dimensionless linear coefficients(uD)obtained fromthe statistical results by the graphic method corresponds to the dimensionless apparent pressure depletion degree of 0.06-0.38,and that obtained based on the data statistics of the example gas reservoir falls within this interval.Fourth,when the starting conditions are not satisfied,the semi-logarithmic type curve matching method can be used for reserve estimation.The ratio of the reserves to the apparent geological reservesG/G_(app) is a function of uD.The higher the uD,the lower the G/G_(app).Fifth,for the high and ultra-high pressure gas reservoirs in the production test stage,the test production time shall be extended as long as possible to improve the reliability of reserve estimation.And for those in the middle and late stages of development,it is necessary to prepare the comprehensive treatment measures on the basis of reserves so as to improve the development effects of gas reservoirs continuously.
基金supported by Research on Reservoir Formation Patterns and Risk Exploration in Key Overseas Basins(25ZYGJCJ011)。
文摘Oilfield M currently has a comprehensive water cut of 73.2%after more than 20 years of development,the reservoir is experiencing both edge-bottom water flooding and injection water flooding,with diverse types of injected water and complex flooding patterns,necessitating the research on logging evaluation methods for water-flooded layers.By introducing the variable multiple injection water material balance theory and combining it with the rock-electric relationship,an analysis of the water flooding mechanism in the study area was conducted.This led to the establishment of the variation characteristics between formation resistivity,water production rate,and saturation under different reservoir types and different salinities of injected water in the area;using the semi-permeable membrane capillary pressure experiment,the relationship between the original formation resistivity and the oil column height was established,deriving the relationship between the water production rate and the formation resistivity drop rate,combining the analysis of the water flooding mechanism mentioned above,allowing for a quantitative assessment of the level of water flooding;optimizing the mixed formation water resistivity calculation model to accurately determine parameters such as remaining oil saturation and water production rate,a set of identification and quantitative evaluation methods for waterflooded layers in Oilfield M was formed.The interpretation accuracy reached 87.5%,providing strong technical support for selecting perforation layers in the oilfield and avoiding highly flooded layers.This is of significant application value for the remaining oil evaluation and efficient development of water-flooded layers in overseas clastic rock oilfields.
文摘Sludge concentration subarea(A area and B area) is realized by mesh filter unit,solving the higher sludge concentration process problem of MBR system under zero excess sludge discharge conditions.Mass balance of the system is processed,and variety disciplinarians of VSS of A area and B area are analyzed.The results show that XA decreases while HRTA increases.XB decreases while R increases,and ascends as VSS(XA,B) of mesh effluent increases.When XB is a fixed value,XA,B increases as R does and XA decreases slowly while R increases,which theoretically proves the feasibility of the technique.
基金funded by the 973 Prophase Special Program of China(NO.2011CB211701)National Natural Science Foundation of China(41172134)CNPC Innovation Foundation (2011D-5006-0101)
文摘The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accumulation. However, there are problems, such as whether high-quality source rocks exist or not？ What high-quality source rocks are, and how to identify them, are yet to be agreed upon. Aimed at this issue of concern to explorationists, and taking the Beier Sag in the Hailaer Basin as an example, this paper defines the high-quality source rocks and the lower limit for evaluation of high-quality source rocks, by using the inflection point on the relationship curve of hydrocarbon （oil） expulsion, which is calculated by the material balance principle, versus total organic carbon （TOC）. The results show that when TOC is low, all source rocks have limited hydrocarbon expulsion and slow growth rate, thus they cannot be high-quality source rocks. However, when TOC rises to some threshold, hydrocarbon expulsion increases significantly with TOC. This inflection point should be the lower limit of high-quality source rocks： those with TOC greater than the inflection-point value are high-quality source rocks. In addition, the lower limit of high-quality source rocks is also related to the type and maturity of organic matters in the source rocks, as well as the mineral components of the source rocks affecting the residual hydrocarbons. Theoretically, the lower limit of high-quality source rocks depends on geological conditions rather than being a constant value. However, for the sake of simplicity and practicability, in this paper TOC=2.0% is regarded as the lower limit of high-quality source rocks. The examination of such standard in the work area indicates that the high-quality source rocks in members K^n2 and K^n~ of the Nantun formation contribute 76% and 82% to oil generation, and 96% and 91% to oil expulsion, respectively. The distribution of high-quality source rocks is also closely related to the distribution of hydrocarbon reservoirs in the region, demonstrating that high-quality source rocks control hydrocarbon accumulation.
基金supported by the National Science and Technology Major Projects of China(No.2016ZX05042 and No.2017ZX05039)the National Natural Science Foundation Projects of China(No.51504269 and No.51490654)Science Foundation of China University of Petroleum,Beijing(No.C201605)to support part of this work。
文摘In this work,a flowing material balance equation(FMBE)is established for under saturated coalbed methane(CBM)reservoirs,which considers immobile free gas expansion effect at the dewatering stage.Based on the established FMBE,five straight-line methods are proposed to determine the control area,initial water reserve,initial free gas reserve,initial adsorbed gas reserve,original gas in place,as well as permeability at the same time.Subsequently,the proposed FMBE methods for undersaturated CBM reservoirs are validated against a reservoir simulation software with and without considering free gas expansion.Finally,the proposed methods are applied in a field case when considering free gas expansion effect.Validation cases show that the straight-line relationships for the proposed five FMBE methods are excellent,and good agreements are obtained among the actual reserves and permeabilities and those evaluated by the proposed five FMBE methods,indicating the proposed five FMBE methods are effective and rational for CBM reservoirs.Results show that a small amount of free gas will result in a great deviation in reserve evaluation;hence,the immobile free gas expansion effect should be considered when establishing the material balance equation of undersaturated CBM reservoirs at the dewatering stage.
基金This work was supported by the Department of Science and Technology of Sichuan Province(2019YFG0457)the National Natural Science Foundation of China(5183000045)+1 种基金the National Major Science and Technology Project of CNPC"Research and Application of Key Technologies for Beneft Development of Volcanic Rock Reservoirs”(2017E-04-05)the PetroChina Major Science and Technology Project(2018E-1805).
文摘Flue gas fooding is one of the important technologies to improve oil recovery and achieve greenhouse gas storage.In order to study multicomponent fue gas storage capacity and enhanced oil recovery(EOR)performance of fue gas water-alternating gas(fue gas-WAG)injection after continuous waterfooding in an oil reservoir,a long core fooding system was built.The experimental results showed that the oil recovery factor of fue gas-WAG fooding was increased by 21.25%after continuous waterfooding and fue gas-WAG fooding could further enhance oil recovery and reduce water cut signifcantly.A novel material balance model based on storage mechanism was developed to estimate the multicomponent fue gas storage capacity and storage capacity of each component of fue gas in reservoir oil,water and as free gas in the post-waterfooding reservoir.The ultimate storage ratio of fue gas is 16%in the fue gas-WAG fooding process.The calculation results of fue gas storage capacity showed that the injection gas storage capacity mainly consists of N_(2) and CO_(2),only N_(2) exists as free gas phase in cores,and other components of injection gas are dissolved in oil and water.Finally,injection strategies from three perspectives for fue gas storage,EOR,and combination of fue gas storage and EOR were proposed,respectively.
基金Projects(KKK0201022137,KKK0201122183) supported by the Special Research Foundation of Yunnan Provincial Environmental Protection Bureau,China
文摘Copper smelting is a significant source of SO2 emission. It is important to quantify SO2 emissions from combustion sources for regulatory and control purposes in relation to air quality. The characteristics of SO2 emissions from copper smelting industry in Yurman Province, China, were examined. Analysis based on the present situation, material balance and measuring method were used to confirm SO2 emission factors of copper smelting industry. Results show that SO2 emission factors for Isa system, side blown-continuous converting system （SB-CC）, blast furnace-continuous converting systems （B-CC） and blast furnace-converter blowing （B-C） are 11.69-18.64, 62.44--101.4, 19.43-37.88 and 45.48-81.03 kg/t（blister copper）, respectively. The comprehensive emission factor based on all smelting plants is found to be in the range of 23-39.99 kg-SO2/t（blister copper） for Yunnan Province, China. The results are compared with those for discharge coefficients of industrial pollutants in the First National General Survey of Pollution Sources and the emission factor of the total amount of major pollutants. It is observed that there are some differences among emission factors.
文摘Based on the principle of thermal balance and material balance of lime furnace, the reaction and heat transfer process mathematical-physical model and the on-line monitoring model of the decomposition rate of limestone were set up. With this model, numerical simulation is used to analyze the effects of operational parameters on the process of lime calcining and to optimize it. By using visual basic program to communicate and program, the centralized management and automatic control of the lime furnace are realized. The software is put into practical production, which makes the lime furnace operate steadily and efficiently, and causes the increase in output and decrease in energy consumption.
文摘This paper presents two methods for easy determination of water influx in reservoirs based on the material balance theory of reservoirs,i.e.,the Net Production Volume Curve,and the Production Index Curve.These methods can be used for esti-ma tion of water influx in reservoirs without any assumption of aquifer shape and size by applying the production performance data.Hence the tedium of the c onventional trial-and-error calculations and obvious uncertainty could be over come in ap plication of the easy and practical new methods.
基金supported by the National Natural Science Foun-dation of China (Grants 40675081 and 40599422)
文摘Aerosol observation was conducted for four seasons from September 2001 to August 2002 at five sampling sites in Hangzhou, South China, on PM10 mass, 22 elements （Na, Mg, AI, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As. Se, Br, Cd, Ba, and Pb）, 5 major ions （F^-, Cl^ , NO3^-, SO4^2- , and NH4^＋）, and organic and elemental carbon （OC and EC）, showing that PM10 mass ranged from 46.7 to 270.8 μg/m^3, with an annual average of 119.2 μg/m^3. Na, AI, Si, S, K, Ca, and Fe were the most abundant elements in PM10, most of S being in the form of SO4^2- . SO4^2-, NO3^-, and NH4^＋ were the major ions, which contributed to about 20% of the PM10 mass. The mean seasonal concentrations for SO4^2- , averaged over all sites, were found to be 18.0, 18.5, 24,Z and 21.4 μg/m^3, for spring, summer, autumn, and winter, respectively, while the corresponding loadings for NO3^- were 7.2, 4.7, 7.1, and 11.2 μg/m^3, and for NH4^＋ were 6.0, 5.9, 8.2, and 9.3 μg/m^3, in the form mostly of NH4NO3 in spring, autumn, and winter, and mostly of （NH4）2SO4 in summer. The low NO3^-/SO4^2- ratio found indicates coal combustion as the major source throughout the year. The mean annual concentrations of OC and EC in PM10 were found to be 21.4, and 4.1 μg/m^3, respectively. Material balance calculation indicated that fugitive dust, the secondary aerosol, and carbonaceous matter were the most abundant species in PM10 for the four seasons, as is characteristic for cities in South China.
基金supported by Beijing Municipal Natural Science Foundation (No.2214077)。
文摘Due to the extremely low permeability of shale formations,the combination of horizontal well and volume fracturing has been proposed as an effective technique to improve the production of Dagang continental shale oil reservoirs.Based on the flow material balance method(FMB)and straight-line analysis(SLA)method,the stimulated reservoir volume(SRV)and drainage volume are determined to identify the flow regimes of the seepage mechanism of shale oil reservoirs.To resolve the challenges of multi-scaled flow regimes and bottom hole pressure(BHP)variation before and after pumping in shale oil wells,a multi-linear analytical flow model was established to predict the future production and the final expected ultimate recoverable oil(EURo)after fitting the historical production dynamics.Based on the results,it can be concluded that the flow regime of a shale oil well in production can be divided into two stages consisting of linear flow within SRV and composite flow from the un-stimulated area to SRV.The effects of fracturing operation parameters,such as fracturing fluid volume and sand/liquid ratio,on shale oil productivity,are analyzed,and insightful suggestions are drawn for the future development of this pay zone.
