This paper provides an introduction to the topic of water shutoff and conformance improvement. After indicating the volumes of water produced during oilfield operations, a strategy is provided for attacking excess wat...This paper provides an introduction to the topic of water shutoff and conformance improvement. After indicating the volumes of water produced during oilfield operations, a strategy is provided for attacking excess water production problems. Problem types are categorized, typical methods of problem diagnosis are mentioned, and the range of solutions is introduced for each problem type. In the third section of the paper, the concept of disproportionate permeability reduction is introduced—where polymers and gels may reduce permeability to water more than to oil or gas. When and where this property is of value is discussed. The fourth section describes the properties of formed gels as they extrude through fractures and how those properties can be of value when treating conformance problems caused by fractures. Section 5 covers the efficiency with which gels block fractures after gel placement—especially, the impact of fluids injected subsequent to the gel treatment.展开更多
The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to b...The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to be more effective in stopping water. Laboratory model test of water shutoff by grouting was conducted. Test results show that the diffusion length and water cutoff effect of the grout are significantly improved as the grout head is raised, due to the dilution of underground water, and it takes the grout longer than its gel time to cut off water.展开更多
Water shutoff in ultralow temperature reservoirs has received great attention in recent years.In previous study,we reported a phenol-formaldehyde-based gel formula with ammonium salt which can provide a gelation time ...Water shutoff in ultralow temperature reservoirs has received great attention in recent years.In previous study,we reported a phenol-formaldehyde-based gel formula with ammonium salt which can provide a gelation time between 2 hrs and 2 days at 25C.However,systematic evaluation and field recommendations of this gel formula when encountering complex reservoirs environment are not addressed.In this paper,how and why such practical considerations as water composition,temperature,pH,weight ratio of formaldehyde to resorcinol and contaminant Fe3t to affect the gelation performance are examined.Brookfield DV-III and scanning electron microscopy(SEM)are employed respectively for viscosity measurement and microstructure analysis.SEM results further illustrate the mechanism of the effect of salinity on gelation performance.It reveals that crosslinking done by covalent bond has great advantage for gel stability under high salinity environment.The target gel formula can provide desirable gelation time below 60C,perfect for 15e45C,while it is unfeasible to use high salinity to delay gelation at 60C.We summarized the effect of salinity on gelation performance of different gel formulas from the present study and published literature.The summarized data can provide important guideline for gel formula design before conducting any kinds of experiments.The variation of gelation performance at different salinity may be dominated by the interaction between crosslinker-salt-polymer,not only limited to“chargescreening effect”and“ion association”proposed by several authors.We hope the analysis encouraging further investigations.Some recommendations for field application of this gel are given in the end of this paper.展开更多
SINCE water emitting in oil wells is a general problem in developing oil fields, the workers inthe world put quite an emphasis on water shutoff. In recent years, the study on develop-ing a novel and highly effective w...SINCE water emitting in oil wells is a general problem in developing oil fields, the workers inthe world put quite an emphasis on water shutoff. In recent years, the study on develop-ing a novel and highly effective water plugging agent has become an important technical mea-sure for controlling water emitting in the middle and later periods of an oil field. A highly ef-fective water plugging agent can form gel, gradually swell in water and shut off water, but oilcan get through. It also has suitable resistance to pressure and high temperature and a longservice life. Only when the water shutoff agent can form a composite polymer network (CPN)展开更多
By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,me...By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.展开更多
文摘This paper provides an introduction to the topic of water shutoff and conformance improvement. After indicating the volumes of water produced during oilfield operations, a strategy is provided for attacking excess water production problems. Problem types are categorized, typical methods of problem diagnosis are mentioned, and the range of solutions is introduced for each problem type. In the third section of the paper, the concept of disproportionate permeability reduction is introduced—where polymers and gels may reduce permeability to water more than to oil or gas. When and where this property is of value is discussed. The fourth section describes the properties of formed gels as they extrude through fractures and how those properties can be of value when treating conformance problems caused by fractures. Section 5 covers the efficiency with which gels block fractures after gel placement—especially, the impact of fluids injected subsequent to the gel treatment.
基金Projects(41472278,41202220)supported by the National Natural Science Foundation of ChinaProject(20120022120003)supported by the Research Fund for the Doctoral Program of Higher Education,China+1 种基金Project(2652012065)supported by the Fundamental Research Funds for the Central Universities,ChinaProject supported by Beijing Higher Education Young Elite Teacher Program,China
文摘The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to be more effective in stopping water. Laboratory model test of water shutoff by grouting was conducted. Test results show that the diffusion length and water cutoff effect of the grout are significantly improved as the grout head is raised, due to the dilution of underground water, and it takes the grout longer than its gel time to cut off water.
基金This work is supported by the National Natural Science Foundation of China(NSFC)under Award No.51404202.
文摘Water shutoff in ultralow temperature reservoirs has received great attention in recent years.In previous study,we reported a phenol-formaldehyde-based gel formula with ammonium salt which can provide a gelation time between 2 hrs and 2 days at 25C.However,systematic evaluation and field recommendations of this gel formula when encountering complex reservoirs environment are not addressed.In this paper,how and why such practical considerations as water composition,temperature,pH,weight ratio of formaldehyde to resorcinol and contaminant Fe3t to affect the gelation performance are examined.Brookfield DV-III and scanning electron microscopy(SEM)are employed respectively for viscosity measurement and microstructure analysis.SEM results further illustrate the mechanism of the effect of salinity on gelation performance.It reveals that crosslinking done by covalent bond has great advantage for gel stability under high salinity environment.The target gel formula can provide desirable gelation time below 60C,perfect for 15e45C,while it is unfeasible to use high salinity to delay gelation at 60C.We summarized the effect of salinity on gelation performance of different gel formulas from the present study and published literature.The summarized data can provide important guideline for gel formula design before conducting any kinds of experiments.The variation of gelation performance at different salinity may be dominated by the interaction between crosslinker-salt-polymer,not only limited to“chargescreening effect”and“ion association”proposed by several authors.We hope the analysis encouraging further investigations.Some recommendations for field application of this gel are given in the end of this paper.
文摘SINCE water emitting in oil wells is a general problem in developing oil fields, the workers inthe world put quite an emphasis on water shutoff. In recent years, the study on develop-ing a novel and highly effective water plugging agent has become an important technical mea-sure for controlling water emitting in the middle and later periods of an oil field. A highly ef-fective water plugging agent can form gel, gradually swell in water and shut off water, but oilcan get through. It also has suitable resistance to pressure and high temperature and a longservice life. Only when the water shutoff agent can form a composite polymer network (CPN)
基金Supported by National Natural Science Foundation of China(51991361,52074327)Major Engineering Technology Field Test Project of CNPC(2020F-45)。
文摘By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.