Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques i...Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques in studying the production contributions of single layers in heavy oil commingled wells has limitations.However,aromatic compounds are relatively well preserved.We took the heavy oil commingled wells of small layers NG55 and NG61 in the ninth area of the Gudong oil field as examples.Based on the principle of chromatography,the whole-oil GC-MS was used,and the aromatic parameters which have a strongly linear relationship with the ratio of mixed two end member oils were verified and selected in laboratory.Studies showed that the ratio of （1,4,6-＋ 2,3,6-trimethylnaphthalene） to 1,2,5-trimethylnaphthalene has a strongly linear relationship with the ratio of the mixed two end member oils （R2=0.992）.The oil contributions from single layers NG55 and NG61 in six commingled heavy oil wells were calculated using established charts and this relationship.The calculated results are consistent with the results of long period dynamic monitoring and logging interpretation in the study area and can provide a scientific basis for monitoring production performance and hierarchical management of reservoirs.The study provides a new geochemical method for calculation of the contributions of single layers in heavy oil commingled wells when conventional fluid production profile logging is not suitable.展开更多
Based on the productivity equation of coalbed methane(CBM) wells, three indexes, main production layer optimization index, main production layer expansion index and capacity contribution index are proposed, with which...Based on the productivity equation of coalbed methane(CBM) wells, three indexes, main production layer optimization index, main production layer expansion index and capacity contribution index are proposed, with which the three-step optimization method of production-layer combination is established. In selecting main production layer, the coal seam thickness, CBM content, coal seam permeability, coal seam reservoir pressure and coal structure are considered comprehensively to evaluate the potential of the production layer. In selecting expansion of the main production layer combination, on the premise of ensuring full and slow desorption of the main production layer and non-exposure of the main production layer out of liquid surface, the degree of mutual interference between the main and non-main production layers is comprehensively evaluated by coupling the critical desorption pressure, layer spacing and reservoir pressure gradient difference. In optimizing production layer combination, the main concern is the economic efficiency of the combined layers. Only when the contribution coefficient of the main production layer is greater than 30% and the contribution index of the other production layers is more than 10%, the economic benefit of a CBM well after being put into production can be ensured. Based on the comparative analysis of the development effect of the development test wells in Songhe of Guizhou province, it is proved that the "three-step method" for the optimization of production-layer combination is scientific and practical, and can be used to design the multi-layer commingling scheme of coalbed methane.展开更多
Based on the established mathematic model and graphic interpretation, a new method, which is used to calculate the contribution of single-zone production in a commingled producing well by the ultraviolet spectrum tech...Based on the established mathematic model and graphic interpretation, a new method, which is used to calculate the contribution of single-zone production in a commingled producing well by the ultraviolet spectrum technique, has been established. The standard plate was drawn using the extinction coefficient E of sample oils formulated artificially as y-axis and the wavelength as x-axis. The curve resulting from the UV analysis of sample oils in the commingled well was inserted into the standard plate and compared. The proportion of each single zone in the commingled producing well was identical with the proportion of the curve which is closest to the curve of sample oils formulated artificially. In the well QHD32-6-3 field, taking well A22 for example and using this method, the production contribution of a single zone was calculated. The result showed that the Nm4 zone is a major "contributor", the proportion of the Nm4 zone is 70%, and that of the Nm1 zone is 30%. The ultraviolet spectrum technique provided a new reservoir geochemical technique of monitoring production contribution, especially for biodegraded heavy oil, but it has some limitation, just depending on the GC fingerprint technique.展开更多
基金supported by the Gudong Oil Production Plant of Shengli Oilfield Subsidiary Company,China Postdoctoral Science Foundation(Project 2013M530681)Hubei Province Natural Science Foundation(Project 2013CFB394)
文摘Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques in studying the production contributions of single layers in heavy oil commingled wells has limitations.However,aromatic compounds are relatively well preserved.We took the heavy oil commingled wells of small layers NG55 and NG61 in the ninth area of the Gudong oil field as examples.Based on the principle of chromatography,the whole-oil GC-MS was used,and the aromatic parameters which have a strongly linear relationship with the ratio of mixed two end member oils were verified and selected in laboratory.Studies showed that the ratio of （1,4,6-＋ 2,3,6-trimethylnaphthalene） to 1,2,5-trimethylnaphthalene has a strongly linear relationship with the ratio of the mixed two end member oils （R2=0.992）.The oil contributions from single layers NG55 and NG61 in six commingled heavy oil wells were calculated using established charts and this relationship.The calculated results are consistent with the results of long period dynamic monitoring and logging interpretation in the study area and can provide a scientific basis for monitoring production performance and hierarchical management of reservoirs.The study provides a new geochemical method for calculation of the contributions of single layers in heavy oil commingled wells when conventional fluid production profile logging is not suitable.
基金Supported by the China National Science and Technology Major Project(2016ZX05044-002)the National Natural Science Foundation of China(41772155)the Fundamental Research Funds for the Central Universities of China(No.2015XKZD07)
文摘Based on the productivity equation of coalbed methane(CBM) wells, three indexes, main production layer optimization index, main production layer expansion index and capacity contribution index are proposed, with which the three-step optimization method of production-layer combination is established. In selecting main production layer, the coal seam thickness, CBM content, coal seam permeability, coal seam reservoir pressure and coal structure are considered comprehensively to evaluate the potential of the production layer. In selecting expansion of the main production layer combination, on the premise of ensuring full and slow desorption of the main production layer and non-exposure of the main production layer out of liquid surface, the degree of mutual interference between the main and non-main production layers is comprehensively evaluated by coupling the critical desorption pressure, layer spacing and reservoir pressure gradient difference. In optimizing production layer combination, the main concern is the economic efficiency of the combined layers. Only when the contribution coefficient of the main production layer is greater than 30% and the contribution index of the other production layers is more than 10%, the economic benefit of a CBM well after being put into production can be ensured. Based on the comparative analysis of the development effect of the development test wells in Songhe of Guizhou province, it is proved that the "three-step method" for the optimization of production-layer combination is scientific and practical, and can be used to design the multi-layer commingling scheme of coalbed methane.
文摘Based on the established mathematic model and graphic interpretation, a new method, which is used to calculate the contribution of single-zone production in a commingled producing well by the ultraviolet spectrum technique, has been established. The standard plate was drawn using the extinction coefficient E of sample oils formulated artificially as y-axis and the wavelength as x-axis. The curve resulting from the UV analysis of sample oils in the commingled well was inserted into the standard plate and compared. The proportion of each single zone in the commingled producing well was identical with the proportion of the curve which is closest to the curve of sample oils formulated artificially. In the well QHD32-6-3 field, taking well A22 for example and using this method, the production contribution of a single zone was calculated. The result showed that the Nm4 zone is a major "contributor", the proportion of the Nm4 zone is 70%, and that of the Nm1 zone is 30%. The ultraviolet spectrum technique provided a new reservoir geochemical technique of monitoring production contribution, especially for biodegraded heavy oil, but it has some limitation, just depending on the GC fingerprint technique.
