Inadequate strength and stability of active crude oil emulsions stabilized by conventional surfactants always lead to a limited plugging rate of plugging agents.Thus,to address this issue,the synthesis of amphiphilic ...Inadequate strength and stability of active crude oil emulsions stabilized by conventional surfactants always lead to a limited plugging rate of plugging agents.Thus,to address this issue,the synthesis of amphiphilic Janus nanosheets was effectively carried out for enhancing the system performances and subsequently characterized.Based on the outcomes of orthogonal tests,an assessment was conducted on the nanosheet and surfactant formulations to optimize the enhancement of emulsion properties.The experimental demonstration of the complex system has revealed its remarkable emulsifying capability,ability to decrease interfacial tension and improve rheological behavior at high temperature(80℃)and high salinity(35,000 ppm)conditions.Involving probable mechanism of the system performance enhancement is elucidated by considering the synergistic effect between surfactants and nanosheets.Furthermore,variables including water-to-oil ratio,salinity,temperature and stirring intensity during operation,which affect the properties of prepared emulsions,were investigated in detail.The efficacy and stability of the complex system in obstructing medium and high permeability cores were demonstrated.Notably,the core with a high permeability of 913.58 mD exhibited a plugging rate of 98.55%.This study establishes the foundations of medium and high permeability reservoirs plugging with novel active crude oil plugging agents in severe environments.展开更多
Recently,foamed polymers have been widely used in the repair of underground engineering disasters by grouting(trenchless technology)due to controllable gelation time and self-expansion.However,the grouting process bec...Recently,foamed polymers have been widely used in the repair of underground engineering disasters by grouting(trenchless technology)due to controllable gelation time and self-expansion.However,the grouting process becomes more complicated due to the complex geological conditions and the self-expansion of slurry.Therefore,this paper adopts a self-made visual experimental device with peripheral pressure and water plugging rate(WPR)monitoring functions to study the influence of main influencing parameters(particle size distribution,grouting amount and dynamic water pump pressure(DWPP))on the spatiotemporal distribution of slurry WPR and diffusion dynamic response(peripheral pressure).The results show that:When grouting amount is 563 g and DWPP is 0.013 MPa,the expansion force of the slurry in the diffusion process is dominant and can significantly change the local sand and gravel skeleton structure.When grouting amount is 563 g,DWPP is 0.013 MPa,and particle size distribution type isⅢ,the flow time of the polymer is shortened,the pores of the gravel are rapidly blocked.Then,the peripheral pressure decreases rapidly with the increase of the distance,and the time to reach the inflection point WPR is shortened.The instantaneous blockage of the pores leads to the delayed transmission of flow field blockage information.展开更多
The finite element method has been applied to simulate the dynamics of a water plugging string in a complex horizontal well of a low-permeability oilfield.The force associated with the pipe string and the packer has b...The finite element method has been applied to simulate the dynamics of a water plugging string in a complex horizontal well of a low-permeability oilfield.The force associated with the pipe string and the packer has been determined under the sucking action of the oil well pump.Such analysis has been conducted for a real drilling well,taking into account the process of lifting,lowering,unblocking and water plugging.Comparison between field measured data and simulation data indicates that the model is reliable and accurate.The packer creep effect under different pressure differences has also been investigated in the framework of the same model.展开更多
In order to find an economic and effective water control method for horizontal wells in deep sea bottom-water gas reservoirs,we prepared modified coated gravel.Based on this,wear resistance,temperature resistance and ...In order to find an economic and effective water control method for horizontal wells in deep sea bottom-water gas reservoirs,we prepared modified coated gravel.Based on this,wear resistance,temperature resistance and water plugging capacity(WPC)tests were carried out on the coated gravel.Then,experiments were carried out using the 3D simulation device for the development of large-scale bottom-water gas reservoirs to compare the development effects of horizontal wells packed with conventional gravel and coated gravel in deepsea bottom-water gas reservoirs.And the following research results were obtained.First,the upper limit of temperature resistance of the gravel coating is 240℃ and the gravel packing speed can reach 4.48 m/s,which is 8 times the average flow velocity of gravel packing in actual open hole sections.Second,as the permeability of the coated gravel packing layer increases,its WPC gets weak.When the permeability is lower than 1500 mD and the displacement pressure difference is lower than 0.6 MPa,the WPC of the coated gravel packing layer is between 0.17 and 0.68.Third,the coated gravel layer functions as gas permeability and water plugging,so the horizontal well technology with coated gravel packing can reduce the flow capacity of water phase breaking into the dominant flow passage,so as to delay the rise of water production of gas well and prolong the gas production time.In this way,the gas recovery factor of bottom-water gas reservoir can be increased effectively.In conclusion,this technology has the function of spontaneous selective water plugging,i.e.,“water plugging in case of water and gas permeability in case of gas”,and its technical and economic advantages are remarkable,which can provide a new idea for the water-control development of deepsea bottom-water gas reservoirs.展开更多
Advanced water injection has become an effective method for developing low-permeability reservoirs.However,after a period of high yield from fracturing,the injected waterflows rapidly along high-capacity channels,which...Advanced water injection has become an effective method for developing low-permeability reservoirs.However,after a period of high yield from fracturing,the injected waterflows rapidly along high-capacity channels,which greatly reduces the sweep efficiency of reservoirs.In this work,the plugging process by microspheres and nanospheres from the fracture to the matrix was simulated through core experiments.The plugging performance of multi-scale microspheres(microspheres and nanospheres)on the core matrix was evaluated by measuring the plugging rate and other parameters.Enhanced oil recovery after synergistic plugging with multi-scale microspheres was used as the evaluation index,a sensitivity analysis of injection parameters was performed,and the best combination of injection parameters was optimized by orthogonal experiments.The experimental results showed that the plugging performance of nanospheres is mainly reflected in thefilling of the core matrix,while the plugging performance of microspheres is mainly reflected by retention at the injection end of the core(as opposed to the fractured end face).The plugging rate of nanospheres reached 78.83%,which is much higher than the 30.28%rate achieved with microspheres.The maximum oil recovery after plugging was 19.12%,which corresponds to the following combination of injection parameters:total injection of 0.6 pore volume(PV),injection ratio between nanospheres and microspheres of 2:1,injection rate of 1.5 mL$min 1,and aging time of 6 days.Among the injection parameters,the injection ratio between nanospheres and microspheres had the greatest influence on the recovery of waterflooding after plugging,followed by the total injection of multi-scale microspheres.The injection rate and aging time had little effect.展开更多
This article outlines the development of separated zone oil production in foreign countries,and details its development in China.According to the development process,production needs,technical characteristics and adap...This article outlines the development of separated zone oil production in foreign countries,and details its development in China.According to the development process,production needs,technical characteristics and adaptability of oilfields in China,the development of separate zone oil production technology is divided into four stages:flowing well zonal oil production,mechanical recovery and water blocking,hydraulically adjustable zonal oil production,and intelligent zonal production.The principles,construction processes,adaptability,advantages and disadvantages of the technology are introduced in detail.Based on the actual production situation of the oilfields in China at present,three development directions of the technology are proposed.First,the real-time monitoring and adjustment level of separated zone oil production needs to be improved by developing downhole sensor technology and two-way communication technology between ground and downhole and enhancing full life cycle service capability and adaptability to horizontal wells.Second,an integrated platform of zonal oil production and management should be built using a digital artificial lifting system.Third,integration of injection and production should be implemented through large-scale application of zonal oil production and zonal water injection to improve matching and adjustment level between the injection and production parameters,thus making the development adjustment from"lag control"to"real-time optimization"and improving the development effect.展开更多
基金financially supported by National Natural Science Foundation of China(52374053)Beijing Natural Science Foundation(2204092)Beijing Municipal Excellent Talent Training Funds Youth Advanced Individual Project(2018000020124G163)。
文摘Inadequate strength and stability of active crude oil emulsions stabilized by conventional surfactants always lead to a limited plugging rate of plugging agents.Thus,to address this issue,the synthesis of amphiphilic Janus nanosheets was effectively carried out for enhancing the system performances and subsequently characterized.Based on the outcomes of orthogonal tests,an assessment was conducted on the nanosheet and surfactant formulations to optimize the enhancement of emulsion properties.The experimental demonstration of the complex system has revealed its remarkable emulsifying capability,ability to decrease interfacial tension and improve rheological behavior at high temperature(80℃)and high salinity(35,000 ppm)conditions.Involving probable mechanism of the system performance enhancement is elucidated by considering the synergistic effect between surfactants and nanosheets.Furthermore,variables including water-to-oil ratio,salinity,temperature and stirring intensity during operation,which affect the properties of prepared emulsions,were investigated in detail.The efficacy and stability of the complex system in obstructing medium and high permeability cores were demonstrated.Notably,the core with a high permeability of 913.58 mD exhibited a plugging rate of 98.55%.This study establishes the foundations of medium and high permeability reservoirs plugging with novel active crude oil plugging agents in severe environments.
基金Project(2022YFC3801000)supported by the National Key Research and Development Program of ChinaProject(232300421064)supported by the Natural Science Foundation of Henan Province,China+1 种基金Project(241111322700)supported by the Key Research and Development Projects in Henan Province,ChinaProject(52008379)supported by the National Natural Science Foundation of China。
文摘Recently,foamed polymers have been widely used in the repair of underground engineering disasters by grouting(trenchless technology)due to controllable gelation time and self-expansion.However,the grouting process becomes more complicated due to the complex geological conditions and the self-expansion of slurry.Therefore,this paper adopts a self-made visual experimental device with peripheral pressure and water plugging rate(WPR)monitoring functions to study the influence of main influencing parameters(particle size distribution,grouting amount and dynamic water pump pressure(DWPP))on the spatiotemporal distribution of slurry WPR and diffusion dynamic response(peripheral pressure).The results show that:When grouting amount is 563 g and DWPP is 0.013 MPa,the expansion force of the slurry in the diffusion process is dominant and can significantly change the local sand and gravel skeleton structure.When grouting amount is 563 g,DWPP is 0.013 MPa,and particle size distribution type isⅢ,the flow time of the polymer is shortened,the pores of the gravel are rapidly blocked.Then,the peripheral pressure decreases rapidly with the increase of the distance,and the time to reach the inflection point WPR is shortened.The instantaneous blockage of the pores leads to the delayed transmission of flow field blockage information.
文摘The finite element method has been applied to simulate the dynamics of a water plugging string in a complex horizontal well of a low-permeability oilfield.The force associated with the pipe string and the packer has been determined under the sucking action of the oil well pump.Such analysis has been conducted for a real drilling well,taking into account the process of lifting,lowering,unblocking and water plugging.Comparison between field measured data and simulation data indicates that the model is reliable and accurate.The packer creep effect under different pressure differences has also been investigated in the framework of the same model.
基金Project supported by Scientific and Technological Project of CNOOC(China)Limited“Study on Key Drilling and Completion Technologies for Deepwater Development Well”(No.:CNOOC-KJ 135 ZDXM 05 LTD 01 SHENHAI 2016).
文摘In order to find an economic and effective water control method for horizontal wells in deep sea bottom-water gas reservoirs,we prepared modified coated gravel.Based on this,wear resistance,temperature resistance and water plugging capacity(WPC)tests were carried out on the coated gravel.Then,experiments were carried out using the 3D simulation device for the development of large-scale bottom-water gas reservoirs to compare the development effects of horizontal wells packed with conventional gravel and coated gravel in deepsea bottom-water gas reservoirs.And the following research results were obtained.First,the upper limit of temperature resistance of the gravel coating is 240℃ and the gravel packing speed can reach 4.48 m/s,which is 8 times the average flow velocity of gravel packing in actual open hole sections.Second,as the permeability of the coated gravel packing layer increases,its WPC gets weak.When the permeability is lower than 1500 mD and the displacement pressure difference is lower than 0.6 MPa,the WPC of the coated gravel packing layer is between 0.17 and 0.68.Third,the coated gravel layer functions as gas permeability and water plugging,so the horizontal well technology with coated gravel packing can reduce the flow capacity of water phase breaking into the dominant flow passage,so as to delay the rise of water production of gas well and prolong the gas production time.In this way,the gas recovery factor of bottom-water gas reservoir can be increased effectively.In conclusion,this technology has the function of spontaneous selective water plugging,i.e.,“water plugging in case of water and gas permeability in case of gas”,and its technical and economic advantages are remarkable,which can provide a new idea for the water-control development of deepsea bottom-water gas reservoirs.
基金funded by the NationalNatural Science Foundation of China(52274056,51974348).
文摘Advanced water injection has become an effective method for developing low-permeability reservoirs.However,after a period of high yield from fracturing,the injected waterflows rapidly along high-capacity channels,which greatly reduces the sweep efficiency of reservoirs.In this work,the plugging process by microspheres and nanospheres from the fracture to the matrix was simulated through core experiments.The plugging performance of multi-scale microspheres(microspheres and nanospheres)on the core matrix was evaluated by measuring the plugging rate and other parameters.Enhanced oil recovery after synergistic plugging with multi-scale microspheres was used as the evaluation index,a sensitivity analysis of injection parameters was performed,and the best combination of injection parameters was optimized by orthogonal experiments.The experimental results showed that the plugging performance of nanospheres is mainly reflected in thefilling of the core matrix,while the plugging performance of microspheres is mainly reflected by retention at the injection end of the core(as opposed to the fractured end face).The plugging rate of nanospheres reached 78.83%,which is much higher than the 30.28%rate achieved with microspheres.The maximum oil recovery after plugging was 19.12%,which corresponds to the following combination of injection parameters:total injection of 0.6 pore volume(PV),injection ratio between nanospheres and microspheres of 2:1,injection rate of 1.5 mL$min 1,and aging time of 6 days.Among the injection parameters,the injection ratio between nanospheres and microspheres had the greatest influence on the recovery of waterflooding after plugging,followed by the total injection of multi-scale microspheres.The injection rate and aging time had little effect.
基金Supported by the National Key Research and Development Program of China(2018YFE0196000)National Science and Technology Major Project of China(2016ZX05010-006)CNPC Scientific Research and Technical Development Project(2019B-4113)
文摘This article outlines the development of separated zone oil production in foreign countries,and details its development in China.According to the development process,production needs,technical characteristics and adaptability of oilfields in China,the development of separate zone oil production technology is divided into four stages:flowing well zonal oil production,mechanical recovery and water blocking,hydraulically adjustable zonal oil production,and intelligent zonal production.The principles,construction processes,adaptability,advantages and disadvantages of the technology are introduced in detail.Based on the actual production situation of the oilfields in China at present,three development directions of the technology are proposed.First,the real-time monitoring and adjustment level of separated zone oil production needs to be improved by developing downhole sensor technology and two-way communication technology between ground and downhole and enhancing full life cycle service capability and adaptability to horizontal wells.Second,an integrated platform of zonal oil production and management should be built using a digital artificial lifting system.Third,integration of injection and production should be implemented through large-scale application of zonal oil production and zonal water injection to improve matching and adjustment level between the injection and production parameters,thus making the development adjustment from"lag control"to"real-time optimization"and improving the development effect.
