The conventional foaming agents have the problems of poor adaptability and high cost during the application in different types of gas fields,especially in high temperature,high salinity,high acidic gas and high conden...The conventional foaming agents have the problems of poor adaptability and high cost during the application in different types of gas fields,especially in high temperature,high salinity,high acidic gas and high condensate oil and gas fields.In this study,the Gemini foaming agent was used as the main agent to enhance foaming and foam stability of the foaming agent,the grafted nanoparticles were used as foam stabilizer to further improve the foam stability,and the characteristic auxiliaries were added to make the foaming agent suitable for different types of gas reservoirs.Two types and six subtypes of nanoparticle foaming agents have been prepared for the main gas fields of China.The experimental evaluation results show that the overall temperature resistance,salinity resistance,H2S resistance,CO2 resistance and condensate resistance of the nanoparticle foaming agents can reach 160℃,250000 mg/L,100 mg/L,100%and 40%,respectively.The new foaming agents have been used in 8685 wells in China.Compared with conventional foaming agent,the average gas flow rate per well increased by 62.48%,the pressure difference(casing-tubing)decreased by 18.9%,and the cost dropped by 45%.The effect of reducing cost and increasing efficiency is obvious.展开更多
Tight oil reservoir development is faced with the key technical problem that"water cannot be injected and oil cannot be produced"yet.With the diphenyl ethers water-soluble(gemini)surfactants as water phase s...Tight oil reservoir development is faced with the key technical problem that"water cannot be injected and oil cannot be produced"yet.With the diphenyl ethers water-soluble(gemini)surfactants as water phase shell and C10–C14 straight-chain hydrocarbon compounds as oil phase kernel,a nanofluids permeation flooding system was prepared by microemulsion technology,and its characteristics and EOR mechanisms were evaluated through experiments.The system has the following five characteristics:(1)"Small-size liquid":the average particle size of the system is less than 30 nm,which can greatly reduce the starting pressure gradient of water injection,and effectively enter and expand the sweep volume of micro-nano matrix;(2)"Small-size oil":the system can break the crude oil into"small-size oil"under the flow condition,which can greatly improve the percolation ability and displacement efficiency of the crude oil in the micro-nano matrix;(3)Dual-phase wetting:the system has contact angles with the water-wet and oil-wet interfaces of(46±1)°and(68±1)°respectively,and makes it possible for capillarity to work fully under complex wetting conditions of the reservoir;(4)High surface activity:the interfacial tension between the system and crude oil from a tight oil reservoir in Xinjiang is 10-3–10-2 mN/m,indicating the system can effectively improve the displacement efficiency of oil in fine pore throats;(5)Demulsification and viscosity reduction:the system has a demulsification and viscosity reduction rate of more than 80%to inversely emulsified crude oil from a tight oil reservoir in Xinjiang,so it can improve the mobility of crude oil in the reservoir and wellbore.The system can be used to increase oil production by fracturing in tight reservoirs,replenish formation energy by reducing injection pressure and increasing injection rate,and enhance oil recovery by displacement and cyclic injection,providing key technical support for effective production and efficient development and recovery enhancement of tight reservoirs.展开更多
Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solu...Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solution polymerization and applied in the field with a new secondary temporary plugging technique. The optimization and performance evaluation of thermo-sensitive temporary plugging agent were carried out through laboratory experiments. The optimized formula is as follows:(6%-8%) acrylamide +(0.08%-0.12%) ammonium persulfate +(1.5%-2.0%) sepiolite +(0.5%-0.8%) polyethylene glycol diacrylate. The thermo-sensitive temporary plugging agent is suitable for formation temperatures of 70-90 ?C, it has high temporary plugging strength(5-40 k Pa), controllable degradation time(1-15 d), the apparent viscosity after degradation of less than 100 m Pa?S and the permeability recovery value of simulated cores of more than 95%. Based on the research results, secondary temporary plugging technique was used in a horizontal well in the Jidong Oilfield. After treatment, the well saw a drop of water cut to 27%, and now it has a water cut of 67%, its daily increased oil production was 4.8 t, and the cumulative oil increment was 750 t, demonstrating that the technique worked well in controlling water production and increasing oil production.展开更多
Most multiphase flow separation detection methods used commonly in oilfields are low in efficiency and accuracy,and have data delay.An online multiphase flow detection method is proposed based on magnetic resonance te...Most multiphase flow separation detection methods used commonly in oilfields are low in efficiency and accuracy,and have data delay.An online multiphase flow detection method is proposed based on magnetic resonance technology,and its supporting device has been made and tested in lab and field.The detection technology works in two parts:measure phase holdup in static state and measure flow rate in flowing state.Oil-water ratio is first measured and then gas holdup.The device is composed of a segmented magnet structure and a dual antenna structure for measuring flowing fluid.A highly compact magnetic resonance spectrometer system and intelligent software are developed.Lab experiments and field application show that the online detection system has the following merits:it can measure flow rate and phase holdup only based on magnetic resonance technology;it can detect in-place transient fluid production at high frequency and thus monitor transient fluid production in real time;it can detect oil,gas and water in a full range at high precision,the detection isn’t affected by salinity and emulsification.It is a green,safe and energy-saving system.展开更多
A smart response fluid was designed and developed to overcome the challenges of gas channeling during CO_(2)flooding in low-permeability,tight oil reservoirs.The fluid is based on Gemini surfactant with self-assembly ...A smart response fluid was designed and developed to overcome the challenges of gas channeling during CO_(2)flooding in low-permeability,tight oil reservoirs.The fluid is based on Gemini surfactant with self-assembly capabilities,and the tertiary amine group serves as the response component.The responsive characteristics and corresponding mechanism of the smart fluid during the interaction with CO_(2)/oil were studied,followed by the shear characteristics of the thickened aggregates obtained by the smart fluid responding to CO_(2).The temperature and salt resistance of the smart fluid and the aggregates were evaluated,and their feasibility and effectiveness in sweep-controlling during the CO_(2)flooding were confirmed.This research reveals:(1)Thickened aggregates could be assembled since the smart fluid interacted with CO_(2).When the mass fraction of the smart fluid ranged from 0.05%to 2.50%,the thickening ratio changed from 9 to 246,with viscosity reaching 13 to 3100 mPas.As a result,the sweep efficiency in low-permeability core models could be increased in our experiments.(2)When the smart fluid(0.5%to 1.0%)was exposed to simulated oil,the oil/fluid interfacial tension decreased to the level of 1×10^(-2)mN/m.Furthermore,the vesicle-like micelles in the smart fluid completely transformed into spherical micelles when the fluid was exposed to simulated oil with the saturation greater than 10%.As a result,the smart fluid could maintain low oil/fluid interfacial tension,and would not be thickened after oil exposure.(3)When the smart fluid interacted with CO_(2),the aggregates showed self-healing properties in terms of shear-thinning,static-thickening,and structural integrity after several shear-static cycles.Therefore,this fluid is safe to be placed in deep reservoirs.(4)The long-term temperature and salt resistance of the smart fluid and thickened aggregates have been confirmed.展开更多
基金Supported by the PetroChina Scientifc Research and Technological Development Project(kt2017-21-14-1).
文摘The conventional foaming agents have the problems of poor adaptability and high cost during the application in different types of gas fields,especially in high temperature,high salinity,high acidic gas and high condensate oil and gas fields.In this study,the Gemini foaming agent was used as the main agent to enhance foaming and foam stability of the foaming agent,the grafted nanoparticles were used as foam stabilizer to further improve the foam stability,and the characteristic auxiliaries were added to make the foaming agent suitable for different types of gas reservoirs.Two types and six subtypes of nanoparticle foaming agents have been prepared for the main gas fields of China.The experimental evaluation results show that the overall temperature resistance,salinity resistance,H2S resistance,CO2 resistance and condensate resistance of the nanoparticle foaming agents can reach 160℃,250000 mg/L,100 mg/L,100%and 40%,respectively.The new foaming agents have been used in 8685 wells in China.Compared with conventional foaming agent,the average gas flow rate per well increased by 62.48%,the pressure difference(casing-tubing)decreased by 18.9%,and the cost dropped by 45%.The effect of reducing cost and increasing efficiency is obvious.
基金Supported by the CNPC Science and Technology Major Project(2019E-2607)RIPED Discipline Construction Project(yjxk2019-12)
文摘Tight oil reservoir development is faced with the key technical problem that"water cannot be injected and oil cannot be produced"yet.With the diphenyl ethers water-soluble(gemini)surfactants as water phase shell and C10–C14 straight-chain hydrocarbon compounds as oil phase kernel,a nanofluids permeation flooding system was prepared by microemulsion technology,and its characteristics and EOR mechanisms were evaluated through experiments.The system has the following five characteristics:(1)"Small-size liquid":the average particle size of the system is less than 30 nm,which can greatly reduce the starting pressure gradient of water injection,and effectively enter and expand the sweep volume of micro-nano matrix;(2)"Small-size oil":the system can break the crude oil into"small-size oil"under the flow condition,which can greatly improve the percolation ability and displacement efficiency of the crude oil in the micro-nano matrix;(3)Dual-phase wetting:the system has contact angles with the water-wet and oil-wet interfaces of(46±1)°and(68±1)°respectively,and makes it possible for capillarity to work fully under complex wetting conditions of the reservoir;(4)High surface activity:the interfacial tension between the system and crude oil from a tight oil reservoir in Xinjiang is 10-3–10-2 mN/m,indicating the system can effectively improve the displacement efficiency of oil in fine pore throats;(5)Demulsification and viscosity reduction:the system has a demulsification and viscosity reduction rate of more than 80%to inversely emulsified crude oil from a tight oil reservoir in Xinjiang,so it can improve the mobility of crude oil in the reservoir and wellbore.The system can be used to increase oil production by fracturing in tight reservoirs,replenish formation energy by reducing injection pressure and increasing injection rate,and enhance oil recovery by displacement and cyclic injection,providing key technical support for effective production and efficient development and recovery enhancement of tight reservoirs.
基金Supported by the National Key Special Science and Technology Project(2016ZX05015-002)PetroChina Key Special Science and Technology Project(2016E-0104)
文摘Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solution polymerization and applied in the field with a new secondary temporary plugging technique. The optimization and performance evaluation of thermo-sensitive temporary plugging agent were carried out through laboratory experiments. The optimized formula is as follows:(6%-8%) acrylamide +(0.08%-0.12%) ammonium persulfate +(1.5%-2.0%) sepiolite +(0.5%-0.8%) polyethylene glycol diacrylate. The thermo-sensitive temporary plugging agent is suitable for formation temperatures of 70-90 ?C, it has high temporary plugging strength(5-40 k Pa), controllable degradation time(1-15 d), the apparent viscosity after degradation of less than 100 m Pa?S and the permeability recovery value of simulated cores of more than 95%. Based on the research results, secondary temporary plugging technique was used in a horizontal well in the Jidong Oilfield. After treatment, the well saw a drop of water cut to 27%, and now it has a water cut of 67%, its daily increased oil production was 4.8 t, and the cumulative oil increment was 750 t, demonstrating that the technique worked well in controlling water production and increasing oil production.
基金Supported by the National Natural Science Foundation of China(51704327)
文摘Most multiphase flow separation detection methods used commonly in oilfields are low in efficiency and accuracy,and have data delay.An online multiphase flow detection method is proposed based on magnetic resonance technology,and its supporting device has been made and tested in lab and field.The detection technology works in two parts:measure phase holdup in static state and measure flow rate in flowing state.Oil-water ratio is first measured and then gas holdup.The device is composed of a segmented magnet structure and a dual antenna structure for measuring flowing fluid.A highly compact magnetic resonance spectrometer system and intelligent software are developed.Lab experiments and field application show that the online detection system has the following merits:it can measure flow rate and phase holdup only based on magnetic resonance technology;it can detect in-place transient fluid production at high frequency and thus monitor transient fluid production in real time;it can detect oil,gas and water in a full range at high precision,the detection isn’t affected by salinity and emulsification.It is a green,safe and energy-saving system.
基金Supported by the PetroChina Science and Technology Major Project(2019-E2607)PetroChina Exploration and Production Company Science and Technology Project(KS2020-01-09).
文摘A smart response fluid was designed and developed to overcome the challenges of gas channeling during CO_(2)flooding in low-permeability,tight oil reservoirs.The fluid is based on Gemini surfactant with self-assembly capabilities,and the tertiary amine group serves as the response component.The responsive characteristics and corresponding mechanism of the smart fluid during the interaction with CO_(2)/oil were studied,followed by the shear characteristics of the thickened aggregates obtained by the smart fluid responding to CO_(2).The temperature and salt resistance of the smart fluid and the aggregates were evaluated,and their feasibility and effectiveness in sweep-controlling during the CO_(2)flooding were confirmed.This research reveals:(1)Thickened aggregates could be assembled since the smart fluid interacted with CO_(2).When the mass fraction of the smart fluid ranged from 0.05%to 2.50%,the thickening ratio changed from 9 to 246,with viscosity reaching 13 to 3100 mPas.As a result,the sweep efficiency in low-permeability core models could be increased in our experiments.(2)When the smart fluid(0.5%to 1.0%)was exposed to simulated oil,the oil/fluid interfacial tension decreased to the level of 1×10^(-2)mN/m.Furthermore,the vesicle-like micelles in the smart fluid completely transformed into spherical micelles when the fluid was exposed to simulated oil with the saturation greater than 10%.As a result,the smart fluid could maintain low oil/fluid interfacial tension,and would not be thickened after oil exposure.(3)When the smart fluid interacted with CO_(2),the aggregates showed self-healing properties in terms of shear-thinning,static-thickening,and structural integrity after several shear-static cycles.Therefore,this fluid is safe to be placed in deep reservoirs.(4)The long-term temperature and salt resistance of the smart fluid and thickened aggregates have been confirmed.
