The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction process.Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristi...The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction process.Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production(EP) analysis,which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. Consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional efficiency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance.展开更多
Saline aquifers are the most popular waste and CO_(2)injection and storage reservoirs worldwide.This project proposes that several optimal injection positions should be investigated as hydraulic pressure-focused posit...Saline aquifers are the most popular waste and CO_(2)injection and storage reservoirs worldwide.This project proposes that several optimal injection positions should be investigated as hydraulic pressure-focused positions,in order to relieve the high demands of pump performance.The comprehensive indices(F_(i))representing the injectivity of different burial depths were obtained by using information entropy,based on the mercury injection experimental data of 13 rock samples.The results demonstrated that the burial depths of No.4,No.1 and No.2 in the Liujiagou Formation were the most suitable positions for hydraulic focused injection,which means the upper 30 m thickness could be regarded as the hydraulic focused range in the saline aquifer with an average thickness of 400 m.In addition,some laboratory experiments and in situ tests were carried out for the purpose of certifying and analyzing results,including SEM,XRD,brittleness index and logging.The results suggested that the rock samples at the No.4,No.1 and No.2 burial depth ranges have loose microstructure,weak cementation,as well as dual pores and fractures.The lithology is mainly quartz and feldspar,but the clay mineral content is high(10%-25%),which is positive for dissolution.The lithology is suitable for hydraulic fracturing to form extended cracks and micro-fissures during high-TDS(total dissolved solids)mine water injection,because of the high brittleness index.Finally,a theoretical and technical framework for high-TDS mine water injection was established,based on operating pilot engineering.Some theoretical defects and drawbacks learned from the field practices were summarized and solutions proposed.The research in this study could provide guidance and a paradigm for the inexpensive treatment of high-TDS mine water by injection and storage.展开更多
基金financially supported by the China Postdoctoral Science Foundation(Grant No.2023M732979 and No.2022TQ0127)the Cooperative Research Project of the Ministry of Education's "Chunhui Program"(Grant No.HZKY20220117)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20220587)the National Natural Science Foundation of China(Grant No.52309112)。
文摘The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction process.Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production(EP) analysis,which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. Consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional efficiency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance.
基金supported by the National Key Research and Development Program of China(No.2023YFC3012103 and No.2019YFC1805400)the National Science Foundation of Jiangsu Province,China(No.BK20210524)+1 种基金the National Natural Science Foundation of China(No.42202268 and No.42172272)the Fundamental Research Funds for the Central Universities,China(No.2020ZDPY0201)。
文摘Saline aquifers are the most popular waste and CO_(2)injection and storage reservoirs worldwide.This project proposes that several optimal injection positions should be investigated as hydraulic pressure-focused positions,in order to relieve the high demands of pump performance.The comprehensive indices(F_(i))representing the injectivity of different burial depths were obtained by using information entropy,based on the mercury injection experimental data of 13 rock samples.The results demonstrated that the burial depths of No.4,No.1 and No.2 in the Liujiagou Formation were the most suitable positions for hydraulic focused injection,which means the upper 30 m thickness could be regarded as the hydraulic focused range in the saline aquifer with an average thickness of 400 m.In addition,some laboratory experiments and in situ tests were carried out for the purpose of certifying and analyzing results,including SEM,XRD,brittleness index and logging.The results suggested that the rock samples at the No.4,No.1 and No.2 burial depth ranges have loose microstructure,weak cementation,as well as dual pores and fractures.The lithology is mainly quartz and feldspar,but the clay mineral content is high(10%-25%),which is positive for dissolution.The lithology is suitable for hydraulic fracturing to form extended cracks and micro-fissures during high-TDS(total dissolved solids)mine water injection,because of the high brittleness index.Finally,a theoretical and technical framework for high-TDS mine water injection was established,based on operating pilot engineering.Some theoretical defects and drawbacks learned from the field practices were summarized and solutions proposed.The research in this study could provide guidance and a paradigm for the inexpensive treatment of high-TDS mine water by injection and storage.
