This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C)in order to provide a theoretical guidance for the rational application of sili...This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C)in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering.Results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C,but when temperature reached above130.C,it would aggravate the bulging degree of thickening curves and significantly extend the thickening time,meanwhile causing the abnormal“temperature-based thickening time reversal”and“dosage-based thickening time reversal”phenomena in the range of 130-160.C and 170-180.C respectively.At 130-160.C,the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH)crystal.The introduced silica fume would be attracted to the cement minerals'surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier”to hinder further hydration of the inner cement minerals.This“adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the“temperature-based thickening time reversal”phenomenon.At 170-180.C,the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated,thus the“temperature-based thickening time reversal”vanished and the“dosage-based thickening time reversal”was presented.展开更多
Based on a carbon fiber cement slurry system developed in the previous work, the relationship between the carbon fiber and the performance of the cement slurry was experimentally investigated. Results show that the us...Based on a carbon fiber cement slurry system developed in the previous work, the relationship between the carbon fiber and the performance of the cement slurry was experimentally investigated. Results show that the use of fiber has no effect on the slurry rheological mode, but influences its rheological behavior. When the fiber proportion ranges from 0.12% to 0.19% and the fiber length from 400 to 1,400 μm, the slurry rheological behavior can be improved. Under the normal pressure, the use of fiber can shorten the thickening time of the cement slurry. When the proportion of the constant-length fiber increases, the water loss of the cement slurry decreases first and then increases, and when the fiber length increases (the fiber proportion being kept constant), the water loss shows the same trend. This indicates that there are optimal values for the fiber length and proportion, which vary under the experimental conditions in the following respective ranges: 0.12%-0.37% and 700-1,400 μm .展开更多
There is low formation pressure coefficient and high formation temperature in ludong-wucaiwan area. Gas cut and gas channeling happen seriously during oil and gas well cementing. The existing anti-migration additive h...There is low formation pressure coefficient and high formation temperature in ludong-wucaiwan area. Gas cut and gas channeling happen seriously during oil and gas well cementing. The existing anti-migration additive has only effects on single trait, so it is difficult to meet cementing requirement. According to this situation we could use latex slurry to anti-gas channeling. We have synthesised a set of anti-gas channeling lightweight temperature-resistant latex slurry and formed a new channeling preventing latex slurry through plenty of previous laboratory experiments. Finally the performance of latex slurry on temperature-resistant, anti-gas channeling and the anti-gas channeling of cement paste are studied. The experimental results show that this latex system has strong temperature-resistant and anti-gas channeling, which completely meet the requirement of cementing in this area.展开更多
Oil and Gas Industry is a Multi-Billion Dollar Industry.Drilling a well is costly,right from exploration to drilling and production to Enhanced Oil Recovery(EOR).Nanotechnology has the potential to introduce revolutio...Oil and Gas Industry is a Multi-Billion Dollar Industry.Drilling a well is costly,right from exploration to drilling and production to Enhanced Oil Recovery(EOR).Nanotechnology has the potential to introduce revolutionary changes in several areas of the oil and gas industry,such as exploration,drilling,cementation,production,EOR,etc.Use of Nanotechnology in the cement slurry can also achieve solutions to some of the problems pertaining to oil well cementation.Nano-silica is a better alternative compared to conventional additives like calcium chloride and silica,because as compared to calcium chloride and silica,the amount of nano-silica to be added is very small.Nano-silica acts as a multi-functional additive.Upon addition of nano-silica to cement slurry,there is a decrease in the thickening time,an increase in the compressive strength,decrease in porosity and permeability within the cement and also a decrease in the fluid loss.Incorporation of nano-silica ensures proper cementation and greater integrity of the well.Nano-silica helps in decreasing the wait on cement(WOC)time and therefore reduces the overall capital cost.Nano-silica is highly recommended for deep offshore wells where high temperature and high pressure are often encountered.This paper discusses the behavior of Nano-silica at high temperatures and also reviews effects of Nano-silica on various properties of cement.展开更多
Nanosilica,when combined with cement slurry aids in improving its compressive strength even,reduces the wait-on-cement time for cement plugs.This study focuses on the synergistic effect of nano-silica in oil and gas w...Nanosilica,when combined with cement slurry aids in improving its compressive strength even,reduces the wait-on-cement time for cement plugs.This study focuses on the synergistic effect of nano-silica in oil and gas well cementing.A comparative study is conducted on the performance of cement slurry(conventional 118 pcf(15.8 lbm/gal))with nanosilica and cement slurry without nano-silica.The cement slurry combined with nano-silica has shown an early compressive strength development in cement slurry at different concentration of silica fume at 10% and 20% by weight of cement.This study also focuses on other areas for improvement including slurry stability,free fluid reduction,lower fluid loss value,fine rheology,appropriate thickening time and higher ultimate compressive strength development.The cement slurry with nano-silica has shown improvement in the compressive strength due to the increased rate of hydration,thus thickening time was within 5hrs.展开更多
基金supported by the Basic Research and Strategic Reserve Technology Research Fund Project of China National Petroleum Corporation (Grant No.2021DQ03-14)the National Natu ral Science Foundation of China (Grant No.52204010)Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C)in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering.Results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C,but when temperature reached above130.C,it would aggravate the bulging degree of thickening curves and significantly extend the thickening time,meanwhile causing the abnormal“temperature-based thickening time reversal”and“dosage-based thickening time reversal”phenomena in the range of 130-160.C and 170-180.C respectively.At 130-160.C,the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH)crystal.The introduced silica fume would be attracted to the cement minerals'surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier”to hinder further hydration of the inner cement minerals.This“adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the“temperature-based thickening time reversal”phenomenon.At 170-180.C,the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated,thus the“temperature-based thickening time reversal”vanished and the“dosage-based thickening time reversal”was presented.
文摘Based on a carbon fiber cement slurry system developed in the previous work, the relationship between the carbon fiber and the performance of the cement slurry was experimentally investigated. Results show that the use of fiber has no effect on the slurry rheological mode, but influences its rheological behavior. When the fiber proportion ranges from 0.12% to 0.19% and the fiber length from 400 to 1,400 μm, the slurry rheological behavior can be improved. Under the normal pressure, the use of fiber can shorten the thickening time of the cement slurry. When the proportion of the constant-length fiber increases, the water loss of the cement slurry decreases first and then increases, and when the fiber length increases (the fiber proportion being kept constant), the water loss shows the same trend. This indicates that there are optimal values for the fiber length and proportion, which vary under the experimental conditions in the following respective ranges: 0.12%-0.37% and 700-1,400 μm .
文摘There is low formation pressure coefficient and high formation temperature in ludong-wucaiwan area. Gas cut and gas channeling happen seriously during oil and gas well cementing. The existing anti-migration additive has only effects on single trait, so it is difficult to meet cementing requirement. According to this situation we could use latex slurry to anti-gas channeling. We have synthesised a set of anti-gas channeling lightweight temperature-resistant latex slurry and formed a new channeling preventing latex slurry through plenty of previous laboratory experiments. Finally the performance of latex slurry on temperature-resistant, anti-gas channeling and the anti-gas channeling of cement paste are studied. The experimental results show that this latex system has strong temperature-resistant and anti-gas channeling, which completely meet the requirement of cementing in this area.
文摘Oil and Gas Industry is a Multi-Billion Dollar Industry.Drilling a well is costly,right from exploration to drilling and production to Enhanced Oil Recovery(EOR).Nanotechnology has the potential to introduce revolutionary changes in several areas of the oil and gas industry,such as exploration,drilling,cementation,production,EOR,etc.Use of Nanotechnology in the cement slurry can also achieve solutions to some of the problems pertaining to oil well cementation.Nano-silica is a better alternative compared to conventional additives like calcium chloride and silica,because as compared to calcium chloride and silica,the amount of nano-silica to be added is very small.Nano-silica acts as a multi-functional additive.Upon addition of nano-silica to cement slurry,there is a decrease in the thickening time,an increase in the compressive strength,decrease in porosity and permeability within the cement and also a decrease in the fluid loss.Incorporation of nano-silica ensures proper cementation and greater integrity of the well.Nano-silica helps in decreasing the wait on cement(WOC)time and therefore reduces the overall capital cost.Nano-silica is highly recommended for deep offshore wells where high temperature and high pressure are often encountered.This paper discusses the behavior of Nano-silica at high temperatures and also reviews effects of Nano-silica on various properties of cement.
文摘Nanosilica,when combined with cement slurry aids in improving its compressive strength even,reduces the wait-on-cement time for cement plugs.This study focuses on the synergistic effect of nano-silica in oil and gas well cementing.A comparative study is conducted on the performance of cement slurry(conventional 118 pcf(15.8 lbm/gal))with nanosilica and cement slurry without nano-silica.The cement slurry combined with nano-silica has shown an early compressive strength development in cement slurry at different concentration of silica fume at 10% and 20% by weight of cement.This study also focuses on other areas for improvement including slurry stability,free fluid reduction,lower fluid loss value,fine rheology,appropriate thickening time and higher ultimate compressive strength development.The cement slurry with nano-silica has shown improvement in the compressive strength due to the increased rate of hydration,thus thickening time was within 5hrs.
