In China, hot researches on shale oil were raised by the important breakthrough of shale oil in America. Obviously, the first important issue is the actual shale oil resource potential of China, and the selection of t...In China, hot researches on shale oil were raised by the important breakthrough of shale oil in America. Obviously, the first important issue is the actual shale oil resource potential of China, and the selection of the key appraisement parameter is vital to the shale oil resource amount. Among the appraisement parameters, the oil content parameter（S1） is the key one, but the evaluation result is generally lower because of light hydrocarbon losing and heavy hydrocarbon handling. And the more important thing is that the light hydrocarbon with small molecular weight is more recoverable, and therefore its amount is important to the total shale oil yields. Based on pyrolysis experiments and the kinetic model of hydrocarbon generation, correction factors and a model of light hydrocarbon losing and heavy hydrocarbon handling were established. The results show that the correction factor of heavy hydrocarbon handling is 3.2, and that of light hydrocarbon losing is controlled by kerogen type, maturity and hydrocarbon generation environment（closed or open）.展开更多
It is a challenge to determine the source and genetic relationship of condensate, waxy and heavy oils in one given complicated petroliferous area, where developed multiple sets of source rocks with different maturity ...It is a challenge to determine the source and genetic relationship of condensate, waxy and heavy oils in one given complicated petroliferous area, where developed multiple sets of source rocks with different maturity and various chemical features.The central part of southern margin of Junggar Basin, NW China is such an example where there are condensates, light oils, normal density oils, heavy crude oils and natural gases. The formation mechanism of condensates has been seriously debated for long time;however, no study has integrated it with genetic types of waxy and heavy oils. Taking the central part of southern margin of Junggar Basin as a case, this study employs geological and geochemical methods to determine the formation mechanism of condensates,waxy and heavy oils in a complicated petroliferous area, and reveals the causes and geochemical processes of the co-occurrence of different types of crude oils in this region. Based on detailed geochemical analyses of more than 40 normal crude oils, light oils,condensates and heavy oils, it is found that the condensates are dominated by low carbon number n-alkanes and enriched in light naphthenics and aromatic hydrocarbons. Heptane values of these condensates range from 19% to 21%, isoheptane values from1.9 to 2.1, and toluene/n-heptane ratios from 1.5 to 2.0. The distribution of n-alkanes in the condensates presents a mirror image with high density waxy crude oils and heavy oils. Combined with the oil and gas-source correlations of the crude oils, condensates and natural gas, it is found that the condensates are product of evaporative fractionation and/or phase-controlled fractionation of reservoir crude oils which were derived from mature Cretaceous lacustrine source rocks in the relatively early stage. The waxy oils are the intermediate products of evaporative fractionation and/or phase-controlled fractionation of reservoir crude oils, while the heavy oils are in-situ residuals. Therefore, evaporative fractionation and/or phase-controlled fractionation would account for the formation of the condensate, light oil, waxy oil and heavy oil in the central part of southern margin of Junggar Basin, resulting in a great change of the content in terms of light alkanes, naphthenics and aromatics in condensates, followed by great uncertainties of toluene/n-heptane ratios due to migration and re-accumulation. The results suggest that the origin of the condensate cannot be simply concluded by its ratios of toluene/n-heptane and n-heptane/methylcyclohexane on the Thompson's cross-plot, it should be comprehensively determined by the aspects of geological background, thermal history of source rocks and petroleum generation,physical and chemical features of various crude oils and natural gas, vertical and lateral distribution of various crude oils in the study area.展开更多
In this study,a sandpack model with porosity and permeability of 32.3%and 9.4 D,and a heavy crude oil with viscosity of 6430 mPa.s were used to represent a typical thin heavy oil formation.First,different ratios of C3...In this study,a sandpack model with porosity and permeability of 32.3%and 9.4 D,and a heavy crude oil with viscosity of 6430 mPa.s were used to represent a typical thin heavy oil formation.First,different ratios of C3H8 to CH4 stream were prepared and their performance on Cyclic Solvent Injection(CSI)method was examined to quantify the optimum solvent concentration.Second,CO2 was introduced to the optimum quantified CH4-C3H8 mixture to investigate the extent to which CSI behavior changes by partially replacement of CH4 with CO2.Results showed that ultimate oil recovery factor(RF)increased from 24.3%to 33.4%original oil in place(OOIP)when C3H8 concentration increased from 15 to 50 mol%in the CH4 stream.CSI tests with higher C3H8 concentration reached the maximum cyclic recovery with lower number of injection cycles-due to higher solubility of C3H8 compared with CH4.Solvent utilization factor(SUF)data also confirmed this as lesser volume of solvent with higher C3H8 concentration was required to produce oil.Visual observations showed that the produced foamy oil lasted longer with higher concentration of C3H8 in the solvent(5 min for 15%C3H8 e 85%CH4 case versus 180min for 50%C3H8 e 50%CH4 case).Upon addition of CO2 to the mixture,the solvent apparent solubility increased and foamy oil flow promoted.The highest cyclic C3H8-CH4 apparent solubility of 0.175 gr.solvent/100 gr.remaining oil jumped to 0.53 gr.solvent/100 gr.remaining oil when 35%mole fraction of CO2 replaced CH4.The highest ultimate oil RF of 44.11%OOIP was measured from eight cycle injection of 50%C3H8 e 15%CH4 e 35%CO2.This solvent also benefited from the longest stability of produced-oil foamy shape with recorded time of 217 min(including production time).According to the results of this experimental study,it seems that there is an optimum fraction of C3H8 in CH4 stream injection in heavy oil systems(with viscosity in the vicinity of 6430 mPa s);the concentration beyond which ultimate oil recovery factor does not increase significantly(near 50 mol%).It is speculated that last cycles do not appreciably respond to heavy oil production mainly due to asphaltene getting precipitated within the model.展开更多
基金supported by "the Fundamental Research Funds for the Central Universities" (14CX05017A)the Natural Science Foundation of China (41330313)+1 种基金Program for New Century Excellent Talents in Heilongjiang Provincial University (1252-NCET-012)CNPC Innovation Foundation (2011D-5006-0101)
文摘In China, hot researches on shale oil were raised by the important breakthrough of shale oil in America. Obviously, the first important issue is the actual shale oil resource potential of China, and the selection of the key appraisement parameter is vital to the shale oil resource amount. Among the appraisement parameters, the oil content parameter（S1） is the key one, but the evaluation result is generally lower because of light hydrocarbon losing and heavy hydrocarbon handling. And the more important thing is that the light hydrocarbon with small molecular weight is more recoverable, and therefore its amount is important to the total shale oil yields. Based on pyrolysis experiments and the kinetic model of hydrocarbon generation, correction factors and a model of light hydrocarbon losing and heavy hydrocarbon handling were established. The results show that the correction factor of heavy hydrocarbon handling is 3.2, and that of light hydrocarbon losing is controlled by kerogen type, maturity and hydrocarbon generation environment（closed or open）.
基金supported by the PetroChina Science and Technology Special Projects (Grant Nos. 06-10A-01-02, 2011A-0201, 2014A-0211 and 2016A-0202)
文摘It is a challenge to determine the source and genetic relationship of condensate, waxy and heavy oils in one given complicated petroliferous area, where developed multiple sets of source rocks with different maturity and various chemical features.The central part of southern margin of Junggar Basin, NW China is such an example where there are condensates, light oils, normal density oils, heavy crude oils and natural gases. The formation mechanism of condensates has been seriously debated for long time;however, no study has integrated it with genetic types of waxy and heavy oils. Taking the central part of southern margin of Junggar Basin as a case, this study employs geological and geochemical methods to determine the formation mechanism of condensates,waxy and heavy oils in a complicated petroliferous area, and reveals the causes and geochemical processes of the co-occurrence of different types of crude oils in this region. Based on detailed geochemical analyses of more than 40 normal crude oils, light oils,condensates and heavy oils, it is found that the condensates are dominated by low carbon number n-alkanes and enriched in light naphthenics and aromatic hydrocarbons. Heptane values of these condensates range from 19% to 21%, isoheptane values from1.9 to 2.1, and toluene/n-heptane ratios from 1.5 to 2.0. The distribution of n-alkanes in the condensates presents a mirror image with high density waxy crude oils and heavy oils. Combined with the oil and gas-source correlations of the crude oils, condensates and natural gas, it is found that the condensates are product of evaporative fractionation and/or phase-controlled fractionation of reservoir crude oils which were derived from mature Cretaceous lacustrine source rocks in the relatively early stage. The waxy oils are the intermediate products of evaporative fractionation and/or phase-controlled fractionation of reservoir crude oils, while the heavy oils are in-situ residuals. Therefore, evaporative fractionation and/or phase-controlled fractionation would account for the formation of the condensate, light oil, waxy oil and heavy oil in the central part of southern margin of Junggar Basin, resulting in a great change of the content in terms of light alkanes, naphthenics and aromatics in condensates, followed by great uncertainties of toluene/n-heptane ratios due to migration and re-accumulation. The results suggest that the origin of the condensate cannot be simply concluded by its ratios of toluene/n-heptane and n-heptane/methylcyclohexane on the Thompson's cross-plot, it should be comprehensively determined by the aspects of geological background, thermal history of source rocks and petroleum generation,physical and chemical features of various crude oils and natural gas, vertical and lateral distribution of various crude oils in the study area.
基金The“Faculty of Graduate Studies and Research(FGSR)of University of Regina”and also“Petroleum Technology Research Centre”are acknowledged for providing financial support in order to carry out this experimental project.
文摘In this study,a sandpack model with porosity and permeability of 32.3%and 9.4 D,and a heavy crude oil with viscosity of 6430 mPa.s were used to represent a typical thin heavy oil formation.First,different ratios of C3H8 to CH4 stream were prepared and their performance on Cyclic Solvent Injection(CSI)method was examined to quantify the optimum solvent concentration.Second,CO2 was introduced to the optimum quantified CH4-C3H8 mixture to investigate the extent to which CSI behavior changes by partially replacement of CH4 with CO2.Results showed that ultimate oil recovery factor(RF)increased from 24.3%to 33.4%original oil in place(OOIP)when C3H8 concentration increased from 15 to 50 mol%in the CH4 stream.CSI tests with higher C3H8 concentration reached the maximum cyclic recovery with lower number of injection cycles-due to higher solubility of C3H8 compared with CH4.Solvent utilization factor(SUF)data also confirmed this as lesser volume of solvent with higher C3H8 concentration was required to produce oil.Visual observations showed that the produced foamy oil lasted longer with higher concentration of C3H8 in the solvent(5 min for 15%C3H8 e 85%CH4 case versus 180min for 50%C3H8 e 50%CH4 case).Upon addition of CO2 to the mixture,the solvent apparent solubility increased and foamy oil flow promoted.The highest cyclic C3H8-CH4 apparent solubility of 0.175 gr.solvent/100 gr.remaining oil jumped to 0.53 gr.solvent/100 gr.remaining oil when 35%mole fraction of CO2 replaced CH4.The highest ultimate oil RF of 44.11%OOIP was measured from eight cycle injection of 50%C3H8 e 15%CH4 e 35%CO2.This solvent also benefited from the longest stability of produced-oil foamy shape with recorded time of 217 min(including production time).According to the results of this experimental study,it seems that there is an optimum fraction of C3H8 in CH4 stream injection in heavy oil systems(with viscosity in the vicinity of 6430 mPa s);the concentration beyond which ultimate oil recovery factor does not increase significantly(near 50 mol%).It is speculated that last cycles do not appreciably respond to heavy oil production mainly due to asphaltene getting precipitated within the model.
