An experimental study of rock-breaking with an offset single cone bit was completed on the bit bench test equipment. Data such as transmission ratio, weight on bit （WOB）, rate of penetration （ROP） and torque on bi...An experimental study of rock-breaking with an offset single cone bit was completed on the bit bench test equipment. Data such as transmission ratio, weight on bit （WOB）, rate of penetration （ROP） and torque on bit were acquired in the experiments. Based on analyzing the experimental results, several conclusions were drawn as follows. The transmission ratio of the offset single-cone bit changed slightly with rotary speed of bit, weight on bit and offset distance. The rate of penetration of the offset singlecone bit increased with increase of WOB and off＇set distance. The torque on bit increased with increase of offset distance under the same WOB and bit rotary speed, decreased with increase of bit rotary speed under the same WOB. The rock-breaking mechanism of the offset single-cone bit was a scraping action. This indicates that the offset single-cone bit is a chipping type bit.展开更多
The attenuation factor or quality factor(Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a m...The attenuation factor or quality factor(Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a method to calculate the Q-factor based on the prestack Q-factor inversion and the generalized S-transform. The proposed method specifies a standard primary wavelet and calculates the cumulative Q-factors; then, it finds the interlaminar Q-factors using the relation between Q and offset(QVO) and the Dix formula. The proposed method is alternative to methods that calculate interlaminar Q-factors after horizon picking. Because the frequency spectrum of each horizon can be extracted continuously on a 2D time–frequency spectrum, the method is called the continuous spectral ratio slope(CSRS) method. Compared with the other Q-inversion methods, the method offers nearly effortless computations and stability, and has mathematical and physical significance. We use numerical modeling to verify the feasibility of the method and apply it to real data from an oilfield in Ahdeb, Iraq. The results suggest that the resolution and spatial stability of the Q-profile are optimal and contain abundant interlaminar information that is extremely helpful in making lithology and fluid predictions.展开更多
A frequency ratio RatioXH associated with two carrier frequencies in ppm is introduced for achieving auto-offsetting and -referencing (AOR) in biomolecular NMR. Once the center of 1H is referenced, all the offsets in ...A frequency ratio RatioXH associated with two carrier frequencies in ppm is introduced for achieving auto-offsetting and -referencing (AOR) in biomolecular NMR. Once the center of 1H is referenced, all the offsets in other dimensions are automatically determined and the centers of the spectral widths provide accurate indirect references. Since the scale in ppm is independent of the magnetic field strength, the AOR does not require manually updating carrier frequencies from time to time, making the multidimensional NMR experiments greatly simplified and reliable. It is extremely valuable when molecules need to be run a large number of experiments at different times and the data (chemical shifts, for example) need to be compared with each other. In AOR, the error arising from improper referencing of 1H is handed down in the same amount to the other nuclei being referenced. This error-inheritance provides a measure of accuracy in indirect referencing. The temperature dependence of the frequency ratio of DSS is derived with the first-order approximation and it can be used for temperature dependent AOR. For nuclei other than 13C, certain frequency ratios regarding TMS need to be derived (rather than measured) based on the recommended frequency ratios of DSS, thus avoiding conflicts and unifying the two standards.展开更多
文摘An experimental study of rock-breaking with an offset single cone bit was completed on the bit bench test equipment. Data such as transmission ratio, weight on bit （WOB）, rate of penetration （ROP） and torque on bit were acquired in the experiments. Based on analyzing the experimental results, several conclusions were drawn as follows. The transmission ratio of the offset single-cone bit changed slightly with rotary speed of bit, weight on bit and offset distance. The rate of penetration of the offset singlecone bit increased with increase of WOB and off＇set distance. The torque on bit increased with increase of offset distance under the same WOB and bit rotary speed, decreased with increase of bit rotary speed under the same WOB. The rock-breaking mechanism of the offset single-cone bit was a scraping action. This indicates that the offset single-cone bit is a chipping type bit.
基金supported by The National Key Research and Development Program Plane(No.2017YFC0601505)National Natural Science Foundation(No.41672325)Science&Technology Department of Sichuan Province Technology Project(No.2017GZ0393)
文摘The attenuation factor or quality factor(Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a method to calculate the Q-factor based on the prestack Q-factor inversion and the generalized S-transform. The proposed method specifies a standard primary wavelet and calculates the cumulative Q-factors; then, it finds the interlaminar Q-factors using the relation between Q and offset(QVO) and the Dix formula. The proposed method is alternative to methods that calculate interlaminar Q-factors after horizon picking. Because the frequency spectrum of each horizon can be extracted continuously on a 2D time–frequency spectrum, the method is called the continuous spectral ratio slope(CSRS) method. Compared with the other Q-inversion methods, the method offers nearly effortless computations and stability, and has mathematical and physical significance. We use numerical modeling to verify the feasibility of the method and apply it to real data from an oilfield in Ahdeb, Iraq. The results suggest that the resolution and spatial stability of the Q-profile are optimal and contain abundant interlaminar information that is extremely helpful in making lithology and fluid predictions.
文摘A frequency ratio RatioXH associated with two carrier frequencies in ppm is introduced for achieving auto-offsetting and -referencing (AOR) in biomolecular NMR. Once the center of 1H is referenced, all the offsets in other dimensions are automatically determined and the centers of the spectral widths provide accurate indirect references. Since the scale in ppm is independent of the magnetic field strength, the AOR does not require manually updating carrier frequencies from time to time, making the multidimensional NMR experiments greatly simplified and reliable. It is extremely valuable when molecules need to be run a large number of experiments at different times and the data (chemical shifts, for example) need to be compared with each other. In AOR, the error arising from improper referencing of 1H is handed down in the same amount to the other nuclei being referenced. This error-inheritance provides a measure of accuracy in indirect referencing. The temperature dependence of the frequency ratio of DSS is derived with the first-order approximation and it can be used for temperature dependent AOR. For nuclei other than 13C, certain frequency ratios regarding TMS need to be derived (rather than measured) based on the recommended frequency ratios of DSS, thus avoiding conflicts and unifying the two standards.
