With the development of deep-buried reservoirs and offshore fields, many prominent problems have been encountered by the use of conventional single artificial lift technologies, which can not meet the requirements of production and may cause frequent workovers. The combination of electrical submersible pump (ESP) and gas lift system (GL), taking advantages of flexible pump rate, relative long workover intervals and simple composition of tubing strings, is considered to be a better solution. The design of ESP-GL combined system is more complicated, referring to the distribution of pressure, temperature and viscosity fields of multiphase flow in the tubing string. In this article, based on the performance curves of lift devices and oil well, the design approach of the ESP-GL combined system based on nodal analysis is established with an example calculation. An optimization design approach of the combined system is then developed by intelligent algorithms, considering some key operating parameters, e.g. pump drainage rate, ESP depth, ESP stages, valve depth and gas injection rate, to find the optimal operating condition of the system. At the same time, the combined lifting system has been successfully applied in some pilot tests in China and Vietnam reporting to have production increments, which suggests a good potential for the application of the ESP-GL combined system in deep fields.
{"title":"System Analysis and Application of Combined System of ESP and Gas Lift","authors":"Ruidong Zhao, Yizhen Sun, Hanjun Zhao, Junfeng Shi, Xishun Zhang, Pengsu Wang, Lihua Ren, Cai Wang, Feng Deng, Shiwen Chen, Guanhong Chen, Yanping Lyu","doi":"10.2118/204703-ms","DOIUrl":"https://doi.org/10.2118/204703-ms","url":null,"abstract":"\u0000 With the development of deep-buried reservoirs and offshore fields, many prominent problems have been encountered by the use of conventional single artificial lift technologies, which can not meet the requirements of production and may cause frequent workovers. The combination of electrical submersible pump (ESP) and gas lift system (GL), taking advantages of flexible pump rate, relative long workover intervals and simple composition of tubing strings, is considered to be a better solution.\u0000 The design of ESP-GL combined system is more complicated, referring to the distribution of pressure, temperature and viscosity fields of multiphase flow in the tubing string. In this article, based on the performance curves of lift devices and oil well, the design approach of the ESP-GL combined system based on nodal analysis is established with an example calculation. An optimization design approach of the combined system is then developed by intelligent algorithms, considering some key operating parameters, e.g. pump drainage rate, ESP depth, ESP stages, valve depth and gas injection rate, to find the optimal operating condition of the system. At the same time, the combined lifting system has been successfully applied in some pilot tests in China and Vietnam reporting to have production increments, which suggests a good potential for the application of the ESP-GL combined system in deep fields.","PeriodicalId":11094,"journal":{"name":"Day 2 Mon, November 29, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79506270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wenguang Duan, Baojiang Sun, Deng Pan, Jianchun Xu, Jian Liu
The shale oil reservoir in Jimusaer has the characteristics of low porosity and low permeability, resulting in significant resistance in oil flow compared with conventional oil reservoirs. Fracturing is needed to increase shale oil production. Supercritical CO2 (SC-CO2) is an ideal choice for fracturing fluid due to its unique physical and chemical properties. SC-CO2 fracturing is able to make CO2 flow into microfractures and greatly reduce the pumping pressure. New progress has been made in the application of the supercritical CO2 fracturing technology in Jimusaer. A phase control model of SC-CO2 fracturing as a function of temperature and pressure is established, which takes into account the SC-CO2 features, intrinsic energy, flow behavior in fracture and fluid filtration. In this paper, the influences of injection pressure and temperature, injection rate, temperature-pressure field, temperature gradient, and phase behavior are analyzed extensively, in addition, the phase control model and its chart of fracture are presented. The proppant accumulation height reduces by a small amount with the increase of the fracturing fluid injection rate. It is necessary to improve the proppant pumping technology by the sand embankment section and proppant concentration. The liquid transforms into supercritical fluid, when flowing in wellbores and fractures. Different fractures have different phase points, and a lower injection temperature is affected by higher injection rate, lower temperature gradient and closer position from transformation point to the end of fracture. Therefore, in order to achieve a better fracturing effect, the injection temperature, pressure, and rate need to be optimized by surface equipment according to the reservoir conditions, to control the phase behavior of CO2. We built a phase control model for the SC-CO2 fracturing technology, which considers temperature control. We also developed some new techniques to improve SC-CO2 fracturing which is critically needed in the Jimusaer oilfield.
{"title":"Recent Advances in Supercritical CO2 Fracturing: New Theory, New Technology, and Application","authors":"Wenguang Duan, Baojiang Sun, Deng Pan, Jianchun Xu, Jian Liu","doi":"10.2118/204725-ms","DOIUrl":"https://doi.org/10.2118/204725-ms","url":null,"abstract":"\u0000 The shale oil reservoir in Jimusaer has the characteristics of low porosity and low permeability, resulting in significant resistance in oil flow compared with conventional oil reservoirs. Fracturing is needed to increase shale oil production. Supercritical CO2 (SC-CO2) is an ideal choice for fracturing fluid due to its unique physical and chemical properties. SC-CO2 fracturing is able to make CO2 flow into microfractures and greatly reduce the pumping pressure. New progress has been made in the application of the supercritical CO2 fracturing technology in Jimusaer.\u0000 A phase control model of SC-CO2 fracturing as a function of temperature and pressure is established, which takes into account the SC-CO2 features, intrinsic energy, flow behavior in fracture and fluid filtration. In this paper, the influences of injection pressure and temperature, injection rate, temperature-pressure field, temperature gradient, and phase behavior are analyzed extensively, in addition, the phase control model and its chart of fracture are presented.\u0000 The proppant accumulation height reduces by a small amount with the increase of the fracturing fluid injection rate. It is necessary to improve the proppant pumping technology by the sand embankment section and proppant concentration. The liquid transforms into supercritical fluid, when flowing in wellbores and fractures. Different fractures have different phase points, and a lower injection temperature is affected by higher injection rate, lower temperature gradient and closer position from transformation point to the end of fracture. Therefore, in order to achieve a better fracturing effect, the injection temperature, pressure, and rate need to be optimized by surface equipment according to the reservoir conditions, to control the phase behavior of CO2.\u0000 We built a phase control model for the SC-CO2 fracturing technology, which considers temperature control. We also developed some new techniques to improve SC-CO2 fracturing which is critically needed in the Jimusaer oilfield.","PeriodicalId":11094,"journal":{"name":"Day 2 Mon, November 29, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87941594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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