Stabilization of Bottom Hole Temperature With Finite Circulation Time and Fluid Flow   总被引：4，自引：1，他引：3  

P. Y. Shen  A. E. Beck 《Geophysical Journal International》1986,86(1):63-90

As an alternative to finite element or finite difference modelling, analytical solutions are derived by the method of Laplace transformation and numerical results obtained for several models of the bottom hole temperature stabilization. Included in the models are the finite circulation time, the thermal property contrast between the borehole mud and the surrounding formation, and the presence of radial or lateral fluid flow in the formation, all of which are found to have significant effects on the dissipation of the thermal disturbance induced by drilling.
The mud circulation is considered to have the effect of either maintaining the borehole mud at a constant temperature or supplying a constant amount of heat per unit length per unit time to the borehole. For small circulation times, the former reduces to the 'zero circulation' model in which the mud circulation creates an instantaneous temperature anomaly at the hole bottom; for small borehole radii, the latter reduces to the line source model and the traditional 'Homer plot'.
For typical drilling operations in which the bottom hole temperatures are measured several hours to several tens of hours after the hole is shut in, the new models generally predict higher equilibrium formation temperatures than does the Horner plot. However, predictions from the various models converge if the BHTs are taken after the hole has been shut in for a period which is greater than about five times the circulation period.  相似文献   

NUMERICAL SIMULATION OF THE MINDANAO EDDY AND TROPICAL CURRENTS OF PACIFIC OCEAN     

李荣凤  曾庆存  季仲贞 《中国海洋湖沼学报》1992,10(3):258-267

Results of numerical simulation of currents in the western North Tropical Pacific Ocean by using a barotropic primitive equation model with fine horizontal resolution agreed well with observations and showed that the Mindanao Cyclonic Eddy located north of the equator and east of Mindanao Island exists during most of the year with monthly (and large seasonal) variations in scope . strength and central location . In June , an anticyclonic eddy occurs northeast of Halmahera Island, strengthens to maximum in August , exists until October and then disappears . The observed large-scale circulation systems such as the North Equatorial Current . the Mindanao Current and the North Equatorial Countercurrent are all very well reproduced in the simulations.  相似文献   

On the principle of maximum entropy and the earthquake frequency–magnitude relation     

P. Y. Shen  L. Mansinha 《Geophysical Journal International》1983,74(3):777-785

  相似文献   

光子计数资料处理方法的比较     

季凯帆 《天文研究与技术》1993,(3)

本文通过对天体测量仪器光子计数模拟资料的处理,比较了13种不同的平滑模型和两种定心算法对最终精度的影响;提出了利用频率域滤波和修正矩方法相结合的最佳处理方法;并对比较结果进行了多方面的讨论。  相似文献   

A VLBI study of 20 southern extragalactic radio sources     

Zhi-qiang Shen  Tong-shan Wan  Xiao-yu Hong  Dong-rong Jiang  Shi-guang Liang 《Chinese Astronomy and Astrophysics》1996,20(4):415-425

This paper describes a 5 GHz VLBI survey in the southern hemisphere. The first observation of 23 extragalactic radio sources was conducted in November 1992. Twenty VLBI images were obtained, of which 15 sources show core-jet structure, one has a two-sided jet, and three sources are unresolved. No compact double source was found. Eleven of the 16 sources with core-jet (including a two-aided jet) show evidence of jet bending. In addition, four sources appear to be superluminal, of which three sources are new.  相似文献   

The physical framework of the dependence between channel flow hydrographs and drainage network morphometry     

J. Garbrecht  H. W. Shen 《水文研究》1988,2(4):337-355

The physical basis of the linkage between magnitude and timing of channel flow hydrographs and drainage network morphometry is reviewed. Small Hortonian and structurally Hortonian networks are analysed using numerical runoff simulation. For Hortonian networks the variability of the geometry of individual channels and subcatchments within each Strahler order has generally little effect upon the overall character of the hydrograph in channels of higher order. If the network is also structurally Hortonian, the analysis of the simultaneous formation, travel, and concentration of the hydrographs in all channels of the network can be simplified to a sequence of one representative hydrograph per channel order. This approach is used in this study. Three major runoff processes control the flow hydrograph characteristics: the overland flow process which determines the water supply to the drainage network; the channel flow process which translates the hydrograph in space and time; and the drainage network process which concentrates and magnifies the flow at the junctions of the drainage network. Functional relations for the hydrograph peak, timing, and flow velocity are presented. For a given uniform rainfall and infiltration rate, the peak of the channel flow hydrograph is shown to increase geometrically with channel order, and its magnitude is directly related to the bifurcation ratio. The travel time of the peak also increases geometrically with channel order, and it is directly related to the channel length ratio over velocity ratio. The flow velocity of the peak changes in a downstream direction as a function of the bifurcation and slope ratio. It was also found that for negligible channel storage the channel flow and drainage network processes do not contribute significantly to the observed nonlinear response of a watershed to precipitation.  相似文献   

1932年麻城6.0级强震的蕴育环境条件探讨     

王清云  李安然  申重阳 《大地测量与地球动力学》1992,(4)

本文在活断层研究和地震宏观调查的基础上,从现代地壳运动特征及活动断层几何学,运动特征等方面研究了1932年麻城Ms6.0级地震的蕴育环境条件,为预测该区强震的地点和强度提供依据。  相似文献   

Geology of Gold Ore Deposits in Western Linyi of Shandong Province,China     

Tiebing Liu  Qingdong Zeng  Yuanchao Shen  Guangming Li 《东北亚地学研究》2003,(1)

1IntroductionWestern Linyi of Shandong Province is one of the most important gold ore mineralization concen-tration areas. Tongjing skarn type gold copper de-posit, Jinchang skarn type gold copper deposit and Duijinshan porphyry type gold deposit were found in 1960's (Edited committee, 1996). Following the discovery of Guilaizhuang gold ore deposit related to alkaline rocks in 1988, the western Linyi region becomes one of the extensively studied areas of gold deposits in China (Lin etal.,…  相似文献   

星际分子正—NH3和He的超精细跃迁碰撞截面和速率系数的理论计算     

陈激  张亚辉 《天文学报》1997,38(3):225-230

本文采用Ｒ矩阵传播方法，通过求解ＣＳ近似下的耦合方程，计算了星际分子云条件下正－ＮＨ３分子和Ｈｅ碰撞的超精细跃迁碰撞截面和速率系数，为研究天体的信息提供需用的基础数据。  相似文献   

Atmosphere-ocean coupling schemes in a one-diemensional climate model     

Ji Jinjun 《大气科学进展》1989,6(3):275-288

In this paper, the coupling schemes of atmosphere-ocean climate models are discussed with one-dimensional advection equations. The convergence and stability for synchronous and asynchronous schemes are demonstrated and compared. Conclusions inferred from the analysis are given below. The synchronous scheme as well as the asynchronous-implicit scheme in this model are stable for arbitrary integrating time intervals. The asynchronous explicit scheme is unstable under certain conditions, which depend upon advection velocities and heat exchange parameters in the atmosphere and oceans. With both synchronous and asynchronous stable schemes the discrete solutions converge to their unique exact ones. Advections in the atmosphere and ocean accelerate the rate of convergence of the asynchronous-implicit scheme. It is suggusted that the asynchronous-implicit coupling scheme is a stable and efficient method for most climatic simulations.  相似文献