The feasibility of gas kick early detection outside the riser was analyzed based on gas-liquid multiphase flow theory.Then an experimental platform for gas kick early detection based on Doppler ultrasonic wave was est...The feasibility of gas kick early detection outside the riser was analyzed based on gas-liquid multiphase flow theory.Then an experimental platform for gas kick early detection based on Doppler ultrasonic wave was established and the propagation experiments in two-phase flow of gas-water(sucrose solutions)were conducted.The time and frequency domains of the Doppler ultrasonic wave signals during the experiments were analyzed.The results show that:(1)No matter the pump was on or off,the detected average Doppler ultrasonic signal voltage increased first and then decreased with the increase of the gas void fraction,and had a quadratic function relation with gas void fraction,so the average voltage change of the monitored signals can be used to deduce the approximate gas void fraction.The Doppler ultrasonic wave signal voltage was significantly reduced in magnitude and variation in the solution with higher viscosity,and the viscosity has stronger impact on the magnitude of signal than density.(2)When the pump was stopped,the Doppler shift increased with the increase of gas void fraction,and the two showed a nearly linear relation,so the detected amount of Doppler shift can reflect the variation of gas void fraction quantitatively.When the pump was on,the sound energy produced by frequency converter had a more significant impact on amplitude spectrum than gas void fraction,so it is impossible to determine whether gas kick occurs by frequency domain signal analysis.(3)This method is a non-contact measurement,with no contact with the drilling fluid and no disruption to the drilling operation.It can quantitatively characterize the gas void fraction according to the change of Doppler ultrasonic signal,enabling earlier detection of gas kick.展开更多
The challenges found in geothermal well drilling have forced the industry to develop new significant cost effective,time saver technologies to go for deeper geothermal resources beyond their traditional limits.To over...The challenges found in geothermal well drilling have forced the industry to develop new significant cost effective,time saver technologies to go for deeper geothermal resources beyond their traditional limits.To overcome these challenges,the new Dual String Drilling(DSD)technology which is based on penetration pathway of drilling fluid and rock cuttings during drilling a well.The principle of DSD employs drilling fluid flows through the annulus of inner and outer string pipe while cutting from the bottom of the well through inner pipe.The paper describes the novel Dual String Drilling(DSD)technology,predicting their occurrence and advantages on drilling of geothermal well.The outcome shows that with DSD approach a lot of time will be saved to circulate the kick out of the well.Additionally,the characteristic response of DSD enables to improve the hole cleaning capacity,to prevent pipe stuck,better well stability,reduction in torque and drag,to remove the dynamic equivalent circulating density gradient in geothermal wells.Moreover,the paper also depicts the system and method for dual coil tubing drilling of horizontal well which follows the same principle as DSD.The comparison of DSD with conventional drilling assesses that the DSD technology is affordable and appropriate for geothermal well drilling.展开更多
基金Supported by Natural Science Foundation of China(51991363)National Program on Key Basic Research Project(973 Program)(2015CB251200)Changjiang Scholars and Innovative Research Team Project(IRT_14R58)
文摘The feasibility of gas kick early detection outside the riser was analyzed based on gas-liquid multiphase flow theory.Then an experimental platform for gas kick early detection based on Doppler ultrasonic wave was established and the propagation experiments in two-phase flow of gas-water(sucrose solutions)were conducted.The time and frequency domains of the Doppler ultrasonic wave signals during the experiments were analyzed.The results show that:(1)No matter the pump was on or off,the detected average Doppler ultrasonic signal voltage increased first and then decreased with the increase of the gas void fraction,and had a quadratic function relation with gas void fraction,so the average voltage change of the monitored signals can be used to deduce the approximate gas void fraction.The Doppler ultrasonic wave signal voltage was significantly reduced in magnitude and variation in the solution with higher viscosity,and the viscosity has stronger impact on the magnitude of signal than density.(2)When the pump was stopped,the Doppler shift increased with the increase of gas void fraction,and the two showed a nearly linear relation,so the detected amount of Doppler shift can reflect the variation of gas void fraction quantitatively.When the pump was on,the sound energy produced by frequency converter had a more significant impact on amplitude spectrum than gas void fraction,so it is impossible to determine whether gas kick occurs by frequency domain signal analysis.(3)This method is a non-contact measurement,with no contact with the drilling fluid and no disruption to the drilling operation.It can quantitatively characterize the gas void fraction according to the change of Doppler ultrasonic signal,enabling earlier detection of gas kick.
文摘The challenges found in geothermal well drilling have forced the industry to develop new significant cost effective,time saver technologies to go for deeper geothermal resources beyond their traditional limits.To overcome these challenges,the new Dual String Drilling(DSD)technology which is based on penetration pathway of drilling fluid and rock cuttings during drilling a well.The principle of DSD employs drilling fluid flows through the annulus of inner and outer string pipe while cutting from the bottom of the well through inner pipe.The paper describes the novel Dual String Drilling(DSD)technology,predicting their occurrence and advantages on drilling of geothermal well.The outcome shows that with DSD approach a lot of time will be saved to circulate the kick out of the well.Additionally,the characteristic response of DSD enables to improve the hole cleaning capacity,to prevent pipe stuck,better well stability,reduction in torque and drag,to remove the dynamic equivalent circulating density gradient in geothermal wells.Moreover,the paper also depicts the system and method for dual coil tubing drilling of horizontal well which follows the same principle as DSD.The comparison of DSD with conventional drilling assesses that the DSD technology is affordable and appropriate for geothermal well drilling.
