Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydra...Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydration.An infrared spectral method and a thermogravimetric technique were used to characterize the chemical composition of the HLMP and evaluate its heat stability.Experiments were conducted to measure the linear swelling,rolling recovery rate,and bentonite inhibition rate and evaluate accordingly the inhibition performance of the HLMP.Moreover,the HLMP was characterized through measurements of the zeta potential,particle size distribution,contact angles,and interlayer space testing.As confirmed by the results,the HLMP could successfully be synthesized with a favorable heat stability.Furthermore,favorable results were found for the inhibitory processes of the HLMP on swelling and dispersed hydration during mud shale hydration.The positively charged HLMP could be electrically neutralized with clay particles,thereby inhibiting diffusion in the double electron clay layers.The hydrophobic group in the HLMP molecular structure resulted in the formation of a hydrophobic membrane on the rock surface,enhancing the hydrophobicity of the rock.In addition,the small molecules of the HLMP could plug the spaces between the layers of bentonite crystals,thereby reducing the entry of water molecules and inhibiting shale hydration.展开更多
This study aims at evaluating the performance of thiamine as a new eco-friendly shale inhibitor in water-based drilling fluids(WBDFs).The evaluation experiments include sedimentation,bentonite inhibition,filtration,ze...This study aims at evaluating the performance of thiamine as a new eco-friendly shale inhibitor in water-based drilling fluids(WBDFs).The evaluation experiments include sedimentation,bentonite inhibition,filtration,zeta potential,thermal gravimetric analysis,scanning electron microscopy,X-ray diffraction,shale cuttings recovery,linear swelling and Fourier transform infrared spectroscopy(FTIR).The performance of thiamine was compared to potassium chloride.In contrast to deionized water,the aqueous solution of thiamine exhibited greater power to inhibit montmorillonite(Mt)dispersion,much more Mt loading capacity(280 g/L)and fluid loss,lower Mt mass loss,larger aggregated Mt particles,lower interlayer space of the Mt particles,less shale cuttings disintegration and lower linear swelling.Adsorption of thiamine on Mt led to a significant shift in the value of zeta potential(from-17.1 to+8.54 mV).Thiamine demonstrated superior inhibitive performance than potassium chloride.FTIR analysis confirmed that thiamine is adsorbed on Mt particles.The compatibility test revealed the compatibility of thiamine with conventional WBDF additives.It was concluded that the main probable inhibition mechanisms of thiamine are the cation exchange and Mt surface coating.In view of its prominent inhibition capacity and great environmental acceptability,thiamine is a promising inhibitor for drilling in water-sensitive formations.展开更多
Wellbore stability is essential for safe and efficient drilling during oil and gas exploration and development.This paper introduces a hydrophobic nano-silica(HNS)for use in strengthening the wellbore wall when using ...Wellbore stability is essential for safe and efficient drilling during oil and gas exploration and development.This paper introduces a hydrophobic nano-silica(HNS)for use in strengthening the wellbore wall when using a water-based drilling fluid(WBF).The wellbore-strengthening performance was studied using the linear swelling test,hot-rolling recovery test,and compressive strength test.The mechanism of strengthening the wellbore wall was studied by means of experiments on the zeta potential,particle size,contact angle,and surface tension,and with the use of a scanning electron microscope(SEM).The surface free energy changes of the shale before and after HNS treatment were also calculated using the contact angle method.The experimental results showed that HNS exhibited a good performance in inhibiting shale swelling and dispersion.Compared with the use of water,the use of HNS resulted in a 20%smaller linear swelling height of the bentonite pellets and an 11.53 times higher recovery of water-sensitive shale—a performance that exceeds those of the commonly used shale inhibitors KCl and polyamines.More importantly,the addition of HNS was effective in preventing a decrease in shale strength.According to the mechanism study,the good wellbore-strengthening performance of HNS can be attributed to three aspects.First,the positively charged HNS balances parts of the negative charges of clay by means of electrostatic adsorption,thus inhibiting osmotic hydration.Second,HNS fabricates a lotus-leaf-like surface with a micro-nano hierarchical structure on shale after adsorption,which significantly increases the water contact angle of the shale surface and considerably reduces the surface free energy,thereby inhibiting surface hydration.Third,the decrease in capillary action and the effective plugging of the shale pores reduce the invasion of water and promote wellbore stability.The approach described herein may provide an avenue for inhibiting both the surface hydration and the osmotic hydration of shale.展开更多
基金The work is supported by the Integration and Testing of Safe and Fast Drilling and Completion Technologies for Complex Ultra-Deep Wells(2020F-46)Major Technology Field Test of Joint-Stock Company(Drilling and Production Engineering).Xuyang received the grant.
文摘Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydration.An infrared spectral method and a thermogravimetric technique were used to characterize the chemical composition of the HLMP and evaluate its heat stability.Experiments were conducted to measure the linear swelling,rolling recovery rate,and bentonite inhibition rate and evaluate accordingly the inhibition performance of the HLMP.Moreover,the HLMP was characterized through measurements of the zeta potential,particle size distribution,contact angles,and interlayer space testing.As confirmed by the results,the HLMP could successfully be synthesized with a favorable heat stability.Furthermore,favorable results were found for the inhibitory processes of the HLMP on swelling and dispersed hydration during mud shale hydration.The positively charged HLMP could be electrically neutralized with clay particles,thereby inhibiting diffusion in the double electron clay layers.The hydrophobic group in the HLMP molecular structure resulted in the formation of a hydrophobic membrane on the rock surface,enhancing the hydrophobicity of the rock.In addition,the small molecules of the HLMP could plug the spaces between the layers of bentonite crystals,thereby reducing the entry of water molecules and inhibiting shale hydration.
文摘This study aims at evaluating the performance of thiamine as a new eco-friendly shale inhibitor in water-based drilling fluids(WBDFs).The evaluation experiments include sedimentation,bentonite inhibition,filtration,zeta potential,thermal gravimetric analysis,scanning electron microscopy,X-ray diffraction,shale cuttings recovery,linear swelling and Fourier transform infrared spectroscopy(FTIR).The performance of thiamine was compared to potassium chloride.In contrast to deionized water,the aqueous solution of thiamine exhibited greater power to inhibit montmorillonite(Mt)dispersion,much more Mt loading capacity(280 g/L)and fluid loss,lower Mt mass loss,larger aggregated Mt particles,lower interlayer space of the Mt particles,less shale cuttings disintegration and lower linear swelling.Adsorption of thiamine on Mt led to a significant shift in the value of zeta potential(from-17.1 to+8.54 mV).Thiamine demonstrated superior inhibitive performance than potassium chloride.FTIR analysis confirmed that thiamine is adsorbed on Mt particles.The compatibility test revealed the compatibility of thiamine with conventional WBDF additives.It was concluded that the main probable inhibition mechanisms of thiamine are the cation exchange and Mt surface coating.In view of its prominent inhibition capacity and great environmental acceptability,thiamine is a promising inhibitor for drilling in water-sensitive formations.
基金the National Natural Science Foundation of China (U1762212 and 51904329)the Shandong Natural Science Foundation (ZR2019BEE002)
文摘Wellbore stability is essential for safe and efficient drilling during oil and gas exploration and development.This paper introduces a hydrophobic nano-silica(HNS)for use in strengthening the wellbore wall when using a water-based drilling fluid(WBF).The wellbore-strengthening performance was studied using the linear swelling test,hot-rolling recovery test,and compressive strength test.The mechanism of strengthening the wellbore wall was studied by means of experiments on the zeta potential,particle size,contact angle,and surface tension,and with the use of a scanning electron microscope(SEM).The surface free energy changes of the shale before and after HNS treatment were also calculated using the contact angle method.The experimental results showed that HNS exhibited a good performance in inhibiting shale swelling and dispersion.Compared with the use of water,the use of HNS resulted in a 20%smaller linear swelling height of the bentonite pellets and an 11.53 times higher recovery of water-sensitive shale—a performance that exceeds those of the commonly used shale inhibitors KCl and polyamines.More importantly,the addition of HNS was effective in preventing a decrease in shale strength.According to the mechanism study,the good wellbore-strengthening performance of HNS can be attributed to three aspects.First,the positively charged HNS balances parts of the negative charges of clay by means of electrostatic adsorption,thus inhibiting osmotic hydration.Second,HNS fabricates a lotus-leaf-like surface with a micro-nano hierarchical structure on shale after adsorption,which significantly increases the water contact angle of the shale surface and considerably reduces the surface free energy,thereby inhibiting surface hydration.Third,the decrease in capillary action and the effective plugging of the shale pores reduce the invasion of water and promote wellbore stability.The approach described herein may provide an avenue for inhibiting both the surface hydration and the osmotic hydration of shale.
